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ЕМ 23-65
BROWNING MACHINE GUN
CALIBER .50 HB, M2
HEADQUARTERS
DEPARTMENT OF THE ARMY
DISTRIBUTION RESTRICTION — Approved for public release; distribution is unlimited.
ЕМ 23-65
С2
Change 2 Headquarters
Department of the Army
Washington, DC, 23 December 2002
Browning Machine Gun
Caliber .50 HB, M2
1. Change FM 23-65, 19 June 1991, as follows:
Remove old pages: Insert new pages:
Pages 1-7 through ТО: анаа на анан rer Pages 1-7 through 1-10
Аррепарс oin ишити rrr n Ep EE Appendix A
Pages C-1 through C-2 .... e opi WM Ada Pages C-1 through C-2
Appendix Ован ноаен аваа новь Appendix О
БАРОТ 7450-R vise ee ber НЕНЫ: DA Form 7450-R
DA Formi 745THa иии йызы ee e EE DA Form 7451-R
References: Pages 1 and 2... de References: Pages 1 and 2
2. A star (*) marks new or changed material.
3. File this transmittal sheet in front of the publication.
DISTRIBUTION RESTRICTION: Approved for public release; distribution is unlimited.
By Order of the Secretary of the Army:
Official:
ERIC K. SHINSEKI
б Uf 2 | General, United States Army
d Chief of Staff
JOEL B. HUDSON
Administrative Assistant to the
Secretary of the Army
0133302
DISTRIBUTION:
Active Army, USAR, and ARNG: To be distributed in accordance with the initial distribution
number 110203, requirements for FM 23-65.
ЕМ 23-65
С1
Сһапде 1 Headquarters
Department of the Army
Washington, DC, 12 September 2001
Browning Machine Gun
Caliber .50 HB, M2
1. Change FM 23-65, 19 June 1991, as follows:
Remove old pages: Insert new pages: Pages
į through IV. аа tei аа r though РРР 4
1-19 through 1-20: act b eon 1-19 through 1-20 eiit oett 2
2-15 through 2-17 iab stuba 2-15 through 2-717 centes 3
3-1 through 34 анааран 3«1 through 394... aic ioco te Leite 4
6-5 through: C- s di etes 6-5 through: СО аа drm erp rette epos 2
C-21 through: -22. чыш шиший ыны C221 through C22 аана нь 2
E-T through F-2 de oso p ipee F-Athrough: F2 215 ep ttr gar e mp 2
момо Appendix аан rao num
Glossary-1 through Glossary-2 ..................... Glossary-1 through Glossary-2 ................... 2
References-1 through References-3 ........... References1 through References-2............ 2
Index-1 through Іпаех-3................................ Index-1 through Іпаех-5.............................. 5
DA Form 7007-R ditor DA Form 7007-R ...... pats 2
——————— — —" DA Form 7448-R : ананна d
M NONO E EE MET DA Form £449-p uiuo neal
"————————— ОЛОК УГУГА. DA Form £450-B eus ьн ne 1
NM PE T DA Form ТЛЕ side inae dete andes
Total pages (not counting this page): ........ 62
2. A star (*) marks new or changed material.
3. File this transmittal sheet in front of the publication.
DISTRIBUTION RESTRICTION: Approved for public release; distribution is unlimited.
By Order of the Secretary of the Army:
Official: ERIC K. SHINSEKI
General, United States Army
pol. 2 ЛЕ MS Chief of Staff
JOEL B. HUDSON
Administrative Assistant to the
Secretary of the Army
0133302
DISTRIBUTION:
Active Army, USAR, and ARNG: To be distributed in accordance with DA Form 12-11E,
requirement for FM 23-65, Browning Machine Gun, Caliber .50 HB, M2 (Qty гаг block no. 0203).
* C1, ЕМ 23-65
FIELD MANUAL HEADQUARTERS
No. 23-65 DEPARTMENT OF THE ARMY
Washington, DC, 19 June 1991
BROWNING MACHINE GUN
CALIBER .50 HB, M2
CONTENTS
Page
PREFACE «eoe odd dat Sota insat eu E e etica iv
CHAPTER 1. INTRODUCTION
1-1. Training Ѕїгаќеду........................................... 1-1
1:25 iDOSCHDHOLD eco tite ved Ы ШЫ ова 1-5
13. Components uoo ара a 1-8
1-4. Ground Mounts онин 1-9
1-5. Accessories for Ground Mounts .................. 1-12
1-6. Vehicular Mounts ........................................ 1-14
1-7. Ammunition 2o2:ioco навора 1-17
CHAPTER 2. MAINTENANCE
25152 Safety CR E ET E D PR PER 2-1
2-2. General ОіѕаѕѕетЫіу.................................... 2-2
2-3. Cleaning, Inspection, and Lubrication ........... 2-9
2-4. Maintenance Procedures ............................ 2-12
2-5. | Maintenance Under NBC Conditions .......... 2-12
2-6. General Assembly....................................... 2-12
2-[. “PUNCORN CHECK аноде 2-17
CHAPTER 3. OPERATION AND FUNCTIONING
adi» Operation адыг 3-1
3-2. Loading Ргосейигеѕ...................................... 3-1
3-3. Unloading Procedures................................... 3-3
3-4. Cycle оҒҒипсііопіпд...................................... 3-4
9-5. Left-hand Feed. es 3-11
3-6. Headspace and Timing ............................... 3-12
DISTRIBUTION RESTRICTION: Approved for public release; distribution
is unlimited.
"This publication supersedes FM 23-65, 19 May 1972, and TC 23-65-1,
19 September 1984.
C1, FM 23-65
C1, FM 23-65
Page
CHAPTER 4. PERFORMANCE PROBLEMS AND DESTRUCTION
He.) . Malfünctiorigc: iiia ree etr lee td ente 4-1
4-2: ."SIODDAOOS umi ete Se aput ant 4-1
4-3. Immediate Асіїоп......................................... .4-2
4-4. Remedial Асіоп............................................ 4-3
4-5. Destruction Procedures ............................... .4-5
CHAPTER 5. MARKSMANSHIP TRAINING
Sectionl. Planning ........................sssseeeeee 5-1
951. ^ - "ODISCIIVES аьаан ies 5-1
5-2. Commander's ResponsibDilities..................... .5-1
5-3. Phases of Training....................................... .5-2
5-4. Sustainment Тгаіпіпд................................... .5-2
5-5. Remedial Тгаіпіпд......................................... 5-2
Section Il. Fundamentals ............................................................. .5-3
5-6. Firing POSITIONS: 2.225 he e diee eos .5-3
5-7. - Огу Fire Training oia atefe rade uera ate aote 5-6
5-8. Range Determination .................................. 5-12
5-9. Observation and Adjustment of Fire .......... .5-16
5-10. Fire Commands .......................................... 5-18
5-11. Crew Ехегсіѕеѕ........................................... 5-22
5-12. Machine Gun Fundamental Skills Test ....... 5-36
Section Ill. Basic Магкѕтапѕћір................................................. .5-36
5-13. Concept of Zeroing/Targeting ..................... 5-36
5-14. 10-Meter Firing Ехегсіѕе............................. 5-41
5-15. Transition Day Firing Exercise .................... 5-41
9516:- МВСВ а ареале .5-41
5-17. Night Fire Exercise .................................... .5-41
Section IV. Advanced Сбиппегу..................................................... 5-41
5-18. Објесімеѕ................................................. .5-42
5-19. Tracking and Leading Exercises ................. 5-42
5-20. Mounted Firing Exercise ............................ 0-45
5-21. Mounted NBC Firing Exercise ................... 0-45
5-22. Predetermined Firing Exercise .................. 0-45
CHAPTER 6. COMBAT TECHNIQUES OF FIRE
Section І. Fundamentals ............................................................ 6-1
6-1. Characteristics of Ғіге................................... 6-1
6-2. Classes of Fire icc iere а Цна аа 6-3
Section Il. Fire СОМОГ: ананна нана анана БЫ 6-7
6-3. Methods of Fire Control ............................... .6-8
6-4. Targets and Their Engagement .................... 6-8
6-5: СОЕ ваа: FING ioco ri erotico aspe 6-14
6-6. Defilade Positions ...................................... .6-18
6-7. Methods of Laying the Gun for
Defilade Firing............................................. 6-20
6-8. Final Protective Fires ................................. .6-21
6-9:- Application of Еге: 6-22
6-10. Fire Adjustment........................................... 6-23
6-11. Antiaircraft Сиппегу................................... .6-25
Section Ill. Limited Visibility Conditions ....................
6-12. Difficulties ...................................
6-13. Terminology ...............................
6-14. Target Engagement ...................
6-15. Fire Control uen
6-16. Preplanned Fires........................
6-17. NBC Considerations...................
CHAPTER 7. TRAIN THE TRAINER PROGRAM
fb -OODBODLou tese aco adeo rad
7-2. Trainer Certification Program .....
7-3. Responsibilities and Duties of
the Тгаіпег..................................
APPENDIX A. ЅАҒЕТҮ.......................................................
APPENDIX B. TRAINING AIDS AND DEVICES ................
APPENDIX C. RANGES AND TRAINING EXERCISES .....
APPENDIX D. FIGHTING POSITIONS ...............................
APPENDIX E. RANGE CARDS ..........................................
APPENDIX F. AERIAL DEFENSE .....................................
APPENDIX С NIGHT OPTICS ...........................................
GLOSSARY ge assece T ——————— Ш СӘ
REFERENCES :........: ee tre набавна
DA Forms
T Glossary-1
References-1
ТЕ Index-1
C1, FM 23-65
C1, FM 23-65
* PREFACE
This manual provides technical information, training techniques, and
guidance on the caliber.50 HB machine gun, M2. Unit leaders and
designated gunners will use this information to successfully integrate the
weapon into combat operations. They can instruct on the range or at
concurrent training stations.
The material applies as is to both nuclear and conventional warfare.
Trainers must ensure that everyone observes safety procedures at all
times. Commanders, trainers, and individual students must remember that
safety is everyone's responsibility. Leaders will conduct all training as
though each weapon were fully loaded. At no time during training will
anyone allow the desire for speed or accuracy to override the requirement
to follow safety procedures. Safe training is good training.
The proponent of this publication is US Army Infantry School. Send
comments and recommendations on DA Form 2028 (Recommended
Changes to Publications and Blank Forms) directly to the Commandant,
US Army Infantry School, ATTN: ATSH-INB-O, Fort Benning, GA
31905-5594 or [email protected].
Unless otherwise stated, the masculine gender refers to both men
and women.
CHAPTER 1
INTRODUCTION
The procedures and methods used in Army machine gun
marksmanship are based on the concept that soldiers must be
skilled gunners who can effectively apply their firing skills in
combat. The basic firing skills and exercises outlined in this
manual must be a part of every unit's machine gun training
program. The soldiers' proficiency depends on proper training
and application of basic gunnery fundamental, which are
taught in a progressive program to prepare gunners for
combat.
1-1. TRAINING STRATEGY
Training strategy is the overall concept for integrating resources into a
program to train individual and collective skills needed to perform a
units wartime mission.
a. Training strategies for marksmanship are implemented in
TRADOC institutions (NCOES, basic and advanced officer's courses) and
in units. The overall training strategy is multifaceted and is inclusive of the
specific strategies used in institution and unit programs. Also included are
the supporting strategies that use resources such as publications, ranges,
ammunition, training aids, devices, simulators, and simulations. These
strategies focus on developing critical soldier skills, and on leader skills
that are required for the intended outcome.
b. Two primary components compose the training strategies: initial
training and sustainment training. Both may include individual and
collective skills. Initial training is critical because a task that is taught
correctly and learned well is retained longer. Well-trained skills can be
more quickly regained and sustained if an interim of nonuse occurs. The
more difficult and complex the task, the harder it is to sustain the skill.
Personnel turnover is a main factor in decay of collective skills, since the
loss of critical team members requires retraining to regain proficiency. If
a long period elapses between initial and sustainment training sessions or
training doctrine is altered, retraining maybe required.
c. The training strategy for caliber .50 MG marksmanship begins in
selected resident training and continues in the unit. An example of this
overall process is illustrated in and provides a concept of the
1-1
ЕМ 23-65
1-2
flow of unit sustainment training. The soldiers graduating from selected
resident training courses have been trained to maintain their MGs and to
hit a variety of targets. They have learned range determination, target
detection, application of marksmanship fundamentals, and other skills
needed to engage a target. Task training during these courses may lead to
qualification.
d. Training continues in units on the basic skills taught in combat
arms. Additional skills, such as suppressive fire and supporting fire, are
trained and then integrated into collective training exercises, which
include platoon and squad live-fire STXs. (A unit-marksmanship training
program is explained in[Chapter 5]) The strategy for sustaining the basic
marksmanship skills taught in combat arms is periodic preliminary
instruction, followed by qualification range firing. However, a unit must
set up a year-round program to sustain skills. Key elements include
training of trainers and refresher training of nonfiring skills.
e. Additional skills trained in the unit include techniques for
employment, suppressive fires, night fire, MOPP firing, and moving
targets. Related soldier skills of camouflage, cover and concealment,
maneuver, and preparation and selection of a fighting position are
addressed in STP 21-24-SMCT, which must be integrated into tactical
training.
f. In the unit, individual and leader proficiency of marksmanship tasks
are integrated into collective training to include squad, section, and
platoon drills and STXs. The collective tasks in these exercises, and how
they are planned and conducted, are in the MTP and battle drill books for
each organization. Based on the type organization, collective tasks are
evaluated to standard and discussed during leader and trainer after-action
reviews. Objective evaluations of both individual and unit proficiency
provide readiness indicators and future training requirements.
g. A critical step in the Army's overall marksmanship training strategy
is to train the trainers and leaders first. Leader courses and unit
publications develop officer and NCO proficiencies necessary to plan and
conduct marksmanship training and to evaluate the effectiveness of unit
marksmanship programs. Training support materials are provided by the
proponent schools to include field manuals, training aids, devices,
simulators, and programs that are doctrinal foundations and guidance for
training the force.
h. Once the soldier understands the weapon and has demonstrated
skill in zeroing, additional live-fire training and a target acquisition
exercise at various ranges are conducted. Target types and scenarios of
increasing difficulty must be mastered to develop proficiency.
1.
ЕМ 23-65
Initial individual training culminates in the soldier's proficiency
assessment, which is conducted on a transition/record fire range. This
evaluation also provides an overview of unit proficiency and training
effectiveness.
j Unit training programs maintain the soldiers' proficiency level. The
ultimate goal of a unit marksmanship program is to maintain well-trained
gunners so a unit can survive and win on the battlefield. The trainer must
realize that qualification is not an end, but a step toward reaching this
combat requirement. (See[Figure 1-1])
(1) To reach this goal, the gunner must be able to position and use his
weapon under the following combat conditions:
(2)
Enemy personnel are seldom visible except when assaulting.
Most combat fire must be directed at an area where the enemy
has been detected or where he is suspected of being located but
cannot be seen. Area targets consist of objects or outlines of men
irregularly spaced along covered and concealed areas (ground
folds, hedges, or borders of woods).
Most combat targets can be detected by smoke, flash, dust, noise,
or movement and are visible only for a moment.
Some combat targets can be engaged by using nearby objects as
reference points.
The nature of the target and irregularities of terrain and
vegetation may require a firer to use a variety of positions in
addition to the prone or supported position to fire effectively on
the target. In a defensive situation, the firer usually fires from a
supported position.
Most combat targets have a low contrast outline and are obscure.
Therefore, choosing an aiming point in elevation is difficult.
Time-stressed fire in combat can be divided into three types: a
single, fleeing target that must be engaged quickly; distributed
targets engaged within the time they remain available; and a
surprise target that must be engaged at once with accurate,
instinctive fire.
The unit’s program must provide fundamental training to sustain
and improve the skills and proficiency the soldier has attained during his
basic marksmanship training. Once basic skills have been mastered, these
must be improved by conducting new or advanced individual and
collective training. The program must develop collective firing skills by
incorporating marksmanship into tactical exercises. This training must
maintain the soldier’s confidence in the weapon and his skills. A soldier’s
ЕМ 23-65
survival may depend on his ability to defend himself or other members of
the unit. Therefore, individual and collective firing skills must support the
expected battlefield conditions and the unit's combat mission.
DETERMINE REQUIREMENTS
Plan/Adjust Training
Calendar Based on:
eMETL
e Goals
eReadiness Levels
eTurnovers
eMissions
eObservance of Deficiencies
ASSESS OVERALL UNIT
PROFICIENCY AND
READINESS
CONDUCT UNIT EVALUATIONS
Train/Review:
eARTEP (MTP, Battle Drills)
eMILES/Live, LTA/MTA
e Varied Missions and
Conditions
eintegrated Individual and
Collective Skills
eEvaluation/Conduct of AAR
TRAIN THE TRAINER
Staff and Unit Leaders:
eintent and Priority
ePublications Review
eldentification of Tasks
ePreparation and Rehearsal
eBasic METL
YEAR-ROUND TRAINING
/ PROGRAM
PERIODIC INTEGRATED
TRAINING TO MAINTAIN
BAND OF EXCELLENCE
AND UNIT READINESS
CONDUCT ADDITIONAL
SKILLS
Preparation:
eNight Fire Skills
eMOPP Skills and Positions
eCamouflage, Cover, and
Concealment
eEmployment Techniques
eModified/Tactical Positions
eAssault/Suppressive Fires
eMoving Targets
eFire and Movement
CONDUCT LIVE-FIRE
Assessment of Individual,
NBC ,and Night Fire.
CONDUCT FTX, STX, and LFX
Assessment of Drills.
CONDUCT PMI
Identify Tasks.
Train/Review (Nonfiring):
eMaintenance and Serviceability
eimmediate-Action Drills
eintegrated Fund
eOther SM Skills
eEvaluation/Remediation
Train/Conduct Initial 10-Meter
and Live-Fire Practice:
eLive-Fire Intergration of Basics
eGroup/Zero Setting
eEvaluation/Remediation
eTarget Detection and Estimation
eWind/Gravity and Adjusted Aim
ePrecise Application of Basics
eLive-Fire Practice at Transition
Range with Feedback
ePractice/Qualification Courses
eEvaluation
CONDUCT BASIC RECORD FIRE
Commander's Evaluation.
Standard or Instructional
Courses.
Assessment of Basic Proficiency.
Readiness.
Figure 1-1. Unit marksmanship sustainment strategy.
1-4
ЕМ 23-65
(3) A unit's marksmanship program must be battlefield oriented. It
must be based upon several individual combat tasks as well as
organizational, operational, or contingency missions. It must have
available resources such as ammunition, time, ranges, and qualified
trainers. This manual provides the information a unit commander needs to
develop an effective marksmanship program for his unit requirements.
(4) General marksmanship, training knowledge, and accurate firing
are acquired skills that perish easily. Skill practice should be conducted for
short periods throughout the year. Most units have a readiness
requirement that all soldiers must zero their MGs within a certain time
after unit assignment. Also, soldiers must confirm the zero of their
assigned MGs before conducting a qualification firing.
1-2. DESCRIPTION
The Browning machine gun caliber .50 HB, M2 (Figure 1-2) is a belt-fed,
recoil-operated, air-cooled, crew-served machine gun. The gun is capable
of single shot, as well as automatic fire, and operates on the short recoil
principle.
RECEIVER BARREL GROUP
BARREL SUPPORT
PINTLE
Figure 1-2. Browning machine gun.
1-5
ЕМ 23-65
1-6
a. The machine gun is capable of being fed from either the right or left
by repositioning certain parts. The weapon has nonfixed headspace that
must be set. Timing must also be adjusted to cause the gun to fire slightly
out of battery to prevent damage to moving parts. The force for recoil
operation is furnished by expanding powder gases, which are controlled by
various springs, cams, and levers. Maximum surface of the barrel and
receiver are exposed to permit air cooling. Perforations in the barrel
support allow air to circulate around the breach end of the barrel and help
in cooling the parts. A heavy barrel is used to retard early overheating.
b. The gun has a leaf-type rear sight (Figure 1-3), graduated in both
yards and roils. The scale ranges from 100 to 2,600 in yards, and from 0 to
62 in mils. The windage knob-permits deflection changes to right or left of
center. The front sight is a fixed blade type with cover (Figure 1-4].
RANGE IN YARDS AND MILS
ELEVATING SCREW KNOB
--
ча ding
a
ae
———
à he
Ф
2s
m
ILE Ld
-- e
as
ә
*
Ld
ә
WINDAGE KNOE
Figure 1-3. Leaf type rear sight.
Figure 1-4. Front sight, cover, and blade.
c. Table 1-1 provides the general data on the caliber .50 MG.
Weight (approx)
Number oftands and grooves [в |
* Point targets, single shot 1,500 meters
Table 1-1. General data.
C2, FM 23-65
1-7
C2, FM 23-65
1-3. COMPONENTS
The major components of the caliber .50 MG and their purposes are shown in
Table 1-2 and Figure 1-5.
Figure 1-5. Components of the caliber .50 MG.
COMPONENTS PURPOSES
l. Barrel Group Houses cartridges for firing; directs projectile.
2. Carrier Assembly Provides handle to carry barrel and to remove
the barrel from the receiver.
. Backplate Group Houses the trigger, bolt latch release, buffer
tube sleeve, and the left and right spade grips.
. Receiver Group Serves as a support for all major components;
houses action of weapon, which controls
functioning of weapon.
5. Bolt Group Provides feeding, chambering, firing, and
extracting, using the propellant gases and
recoil spring for power.
6. Cover Group Feeds linked belt ammunition; positions and
holds cartridges in position for extracting,
feeding, and chambering.
7. Bolt Stud Provides a means to move the bolt to the rear
with the retracting slide handle.
8. Barrel Extension Group Secures the barrel to the recoiling parts.
9. Barrel Buffer Body Assists in recoil and counterrecoil of the bolt
group.
10. Driving Spring Rod Drives the bolt forward when the bolt latch
Assembly release is depressed.
Table 1-2. Components and their purposes.
1-4. GROUND MOUNTS
The two principal ground mounts used with the caliber .50 machine gun are the
tripod mount, M3, and the antiaircraft mount, M63. The tripod mount, M3, is a
ground mount designed for use against ground targets. The antiaircraft mount,
C2, FM 23-65
C2, FM 23-65
M63, is a ground mount principally designed for use against aerial targets. Its use
against ground targets is limited because the mount tends to be unstable when the
gun is fired at low angles.
a. Tripod Mount, M3. The M3 mount is the standard ground mount of the
caliber .50 machine gun (Figure 1-6). It is a folding tripod with three, telescopic,
tubular legs connected at the tripod head. Each leg ends in a metal
shoe that can be stamped into the ground for greater stability. The two trail legs
are joined together by the traversing bar. The traversing bar serves as a support
for the traversing and elevating mechanism, which in turn supports the rear of the
gun. The tripod head furnishes a front support for the mounted gun that is further
supported by the short front leg. When the tripod is emplaced on flat terrain with
all extensions closed, the adjustable front leg should form an angle of about 60
degrees with the ground. This places the gun on a low mount about 12 inches
above the ground. To raise the tripod farther off the ground, extend the telescopic
front and trail legs enough to keep the tripod level and maintain the stability of the
mount.
T&E MECHANISM
TRAIL LEGS
S N
PINTLE LOCK
RELEASE CAM
INDEXING LEVER
ASSEMBLY
ONT LEG
FR
REAR RIGHT LEG
SLIDING SLEEVE „тинин
Figure 1-6. M3 tripod mount.
(1) To set the tripod trail legs--
(a) Unscrew the leg-clamping handle, press down on the indexing lever, and
extend the leg to the desired length.
(b) Align the indexing lever stud with one of the holes in the tripod leg
extension.
(c) Release the pressure on the indexing lever, allowing the stud to fit the
desired hole. Tighten the leg-clamping handle.
1-10
ЕМ 23-65
(2) To set the front leg of the tripod-
(a) Turn the front leg clamp handle counterclockwise to loosen the
front leg.
(b) Adjust the leg to the desired angle and tighten the front leg clamp.
(3) To secure the tripod legs, stamp the metal shoe on each tripod leg
into the ground. Sandbag each leg to stabilize the M2 for firing.
b. Antiaircraft Mount, M63. The antiaircraft mount (Figure 1-7) is a
four-legged, low silhouette, portable mount used for antiaircraft fire.
lists the general data pertaining to the M63.
zd »
Figure 1-7. Antiaircraft mount, M63.
WEIGHTS:
VOT ANE ыыы ————— —— ——— 144 pounds
ag. e —————— 24 pounds
Base assembly насаа ааваараа вена анана ананан 54 pounds
Elevator assembly ..................................................................у 12 pounds
Cradle аззетЬ!у..................................................................... 44 pounds
Ammunition box-tray assembly ............................................. 10 pounds
HEIGHT OVERALL ооо saspsauteaavacancesbansnscdasternsedensaveciecs: 42 inches
LENGTH OF LEG ...-.. "m 24 inches
DIAMETER OF BASE (WITH LEG А$$ЕМВГЕР)............................ 52 inches
MAXIMUM ELEVATION ................................. «а. нае 85 degrees
MAXIMUM DEPRESSION .......................................... анне 29 degrees
MAXIMUM TRAVERSE .................sccccsssssccssscsensccsecesenseesesenseesensee 360 degrees
Table 1-3. M63 general data.
1-11
ЕМ 23-65
1-12
1-5. ACCESSORIES FOR GROUND MOUNTS
The following paragraph explains the functions of the traversing and
elevating mechanism and pintle used in the mounting of the machine gun
when used in the ground configuration.
a. Traversing and Elevating Mechanism. The T&E mechanism
(Figure 1-8) is used to engage preselected target areas at night or during
limited visibility conditions. Record direction and elevation readings from
the traversing bar and T&E mechanism. Record all readings in mils.
(1) The traversing mechanism consists of a traversing bar, slide, and
screw assembly.
(a) The traversing bar, graduated in 5-roil increments, fits between the
trail legs of the tripod. The traversing slide and screw assembly are
clamped in place on the traversing bar by the traversing slide lock lever.
When the traversing slide is locked to the traversing bar, the traversing
handwheel should be centered. The traversing slide is properly mounted
when the lock lever is to the rear and the traversing handwheel is
positioned to the left.
(b) To make changes in direction, loosen the traversing slide lock
lever and move the slide along the traversing bar. This permits traverse of
400 mils left or right of the zero index in the center of the traversing bar.
Readings on the traversing bar are taken from the left side of the
traversing slide. For changes of 50 mils or less in deflection, turn the
traversing handwheel of the screw assembly. This allows a traverse of 50
mils left or right of center. One click in the traversing handwheel signifies
] mil change in direction.
(2) The elevating mechanism consists of an upper and lower elevating
screw.
(a) It is connected to the gun by inserting the quick release pin
assembly through the holes in the upper elevating screw yoke and the rear
mounting lugs of the receiver. A scale, graduated in mils, is fitted to the
upper screw to indicate elevation. This scale is marked to show 250 mils in
depression and 100 mils in elevation from the zero setting.
(b) The elevating handwheel is graduated in l-mil increments up to 50
mils, and is fastened to the elevating screw by a screw lock. This
synchronizes the handwheel graduations with those on the upper elevating
screw. A spring-actuated index device produces a clicking sound when the
handwheel is turned. Each click equals 1 mil change in elevation. The
handwheel is turned clockwise to depress the barrel and counterclockwise
to elevate.
TRAVERSING, .
HANDWHEEL
ELEVATION SCREW .
SCALE PLATE TA ELEVATION
HANDWHEEL
100 0
np mtt
Figure 1-8. Traversing and elevating mechanism.
b. Pintle. The gun is connected to the tripod mount, M3, by a pintle
page 1-14). This pintle is semipermanently attached to the
machine gun by a pintle bolt through the front mounting hole in the
receiver. The tapered stem of the pintle seats in the tripod head. It is held
secure by a pintle lock and spring. To release the pintle, raise the pintle
lock, releasing the cam. The weight of the pintle and traversing and
elevating mechanism are considered as part of the total weight of the
tripod mount, M3 (44 pounds).
FM 23-65
ЕМ 23-65
1-14
Figure 1-9. Pintle.
1-6. VEHICULAR MOUNTS
The four principal vehicular mounts used with the caliber .50 machine gun
are the truck mount, M36; the pedestal truck mount, M31C and M24A2;
the commander's cupola, MII3 armored personnel carrier; and the MK64
gun cradle.
a. Truck Mount, M36. This mount consists of a cradle with a roller
carriage on a circular track (Figure 1-10]. The cradle can be rotated in the
pintle sleeve of the carriage and can be adjusted for elevation. The
carriage is guided on the track by rollers. The track is secured to the
vehicle by supports.
(1) To move the gun in elevation on the M36 mount, remove the
cradle locking pin and place it in the carriage handle; grasp the spade grips
and elevate or depress as desired. The gun is also moved in traverse by
pressure on the spade grips.
(2) To move the gun on the track, raise the brake handle lever until it
is retained by the brake detent plungers. The cradle may then be moved
on the track by applying pressure on the carriage handle.
b. Pedestal Truck Mount, M31C. Pedestal mounts are component
assemblies designed for installation on the 1/4-ton vehicles to support a
machine gun mount. They are composed of a pintle socket, pintle
clamping screw column, and braces (Figure 1-11).
c. Armored Vehicle Cupola Mount. A caliber .50 machine gun and
mount are installed in the gun support on the commander's cupola of an
MI 13 armored personnel carrier. The machine gun can be traversed
360 degrees, elevated 53 degrees, and depressed 21 degrees maximum
(Figure 1-12).
ЕМ 23-65
Figure 1-10. Truck mount, M36.
Figure 1-11. Pedestal truck mount, M31 C.
1-15
ЕМ 23-65
Figure 1-12. Cupola mount.
d. MK64 Gun Cradle Mount. This vehicle mount was primarily
designed for the M2. However, because of its versatility, the MK64 will
accept the MK 19 also (using the M2 mounting adapter assembly). The
MK64 can be mounted on the following vehicles — M151 series, M966
HMMWV armament carrier, and the M113 series (Figure 1-13).
Figure 1-13. MK64 gun cradle.
1-7. AMMUNITION
This paragraph describes the ammunition used in caliber .50 machine guns
(Figure 1-14). Soldiers should be able to recognize the types of
ammunition available and know how to care for it. The caliber .50
cartridge consists of a cartridge case, primer, propelling charge, and the
bullet. See TM 9-1300-200. The term bullet refers only to the small-arms
projectile. There are eight types of ammunition issued for use in the
caliber .50 machine gun. The tips of the various rounds are color-coded to
indicate their type. The ammunition is linked with the M2 or M9 metallic
links for use in the machine gun (Figure 1-15| page 1-18).
NATURAL RED MAROON BLACK BLUE’ LIGHT ALUMINUM BLUE/ RED/
OR ORANGE BLUE ALUMINUM ALUMINUM
NATURAL
BALL TRACER ARMOR- INCENDIARY ARMOR- ARMOR- DUMMY BLANK
PIERCING PIERCING PIERCING
INCENDIARY INCENDIARY-
TRACER
Figure 1-14. Ammunition for the M2.
a. Classification. The eight types of ammunition are used for the
following purposes.
(1) Ball. For use in marksmanship training, and against personnel and
light material targets.
(2) Tracer. To aid in observing fire. Secondary purposes are for
incendiary effect and for signaling.
(3) Armor-piercing. For use against armored aircraft and lightly
armored vehicles, concrete shelters, and other bullet-resisting targets.
(4) Incendiary. For incendiary effect, especially against aircraft.
FM 23-65
1-17
ЕМ 23-65
(5) Armor-piercing-incendiary. For combined armor-piercing and
incendiary effect.
(6) Armor-piercing-incendiary-tracer. For combined armor-piercing
and incendiary effect, with the additional tracer feature.
(7) Blank. For simulated fire (contains no bullet).
(8) High-pressure test. For use only in proof firing of weapons and
barrels.
(9) Dummy. For training (completely inert).
BB
CALIBER 50. M2 CALIBER 50. M9
Figure 1-15. М2 and M9 links (closed loop).
b. Ballistic Data. The approximate maximum range and average
muzzle velocity of some of the different types of caliber .50 ammunition
authorized for use in the machine gun are noted in Table 1-4.
MAXIMUM AVERAGE
RANGE MUZZLE VELOCITY
CARTRIDGE (meters) (feet per second)
2,930
Armor-piercing-incendiary,M8
Armor-piercing-incendiary-
tracer, M20
* This tracer is dim at near ranges but increases to bright as it moves
farther from the gun.
Table 1-4. Ballistic data.
1-18
c. Care, Handling, and Preservation. Exercise care to prevent
ammunition boxes from becoming broken or damaged. If they do, repair
them immediately. Transfer all original markings to the new parts of the
box. Do not open ammunition boxes until the ammunition is to be used.
Ammunition removed from the airtight container, particularly in damp
climates, is likely to corrode. Protect the ammunition from mud, sand, and
water. If the ammunition gets wet or dirty, wipe it off at once with a
clean, dry cloth. Wipe off light corrosion as soon as it is discovered. Turn
in heavily corroded cartridges. Do not expose ammunition to the direct
rays of the sun. If the powder is hot, excessive pressure may be developed
when the weapon is fired. Do not oil or grease ammunition. Dust and
other abrasives that collect on greasy ammunition are injurious to the
operating parts of the gun. Moreover, oiled cartridges produce excessive
chamber pressure. Do not fire dented cartridges, cartridges with loose
bullets, or otherwise defective rounds.
d. Storage. Small-arms ammunition is not an explosive hazard, but
under poor storage conditions it may become a fire hazard. Store
ammunition of all classes away from radiators, hot water pipes, and other
sources of heat. Whenever possible, store ammunition under cover. If it
is necessary to leave ammunition in the open, keep it at least 6 inches off
the ground and covered with a double thickness of tarpaulin. Place the
tarpaulin so that it gives maximum protection and allows free circulation
of air. Dig suitable trenches to prevent water from flowing under the
ammunition pile.
e. Miscellaneous Data. Table 1-5 lists the maximum penetration in
inches for an armor-piercing cartridge fired from the 45-inch barrel
(muzzle velocity, 2,935 feet per second), which in some cases may
enhance the leader's selection of targets to engage.
INCHES AT:
200 600 1,500
MATERIAL METERS | METERS | METERS
Armor plate (homogeneous) 1.0 0.7 0.3
Armor plate (face-hardened) 0.9 0.5 0.2
Sand (100 pounds dry weight/cubic feet) 14.0 12.0 16.0
Clay (100 pounds dry weight/cubic feet) 28.0 27.0 21.0
Table 1-5. Maximum penetration for armor-piercing cartridge.
C1, FM 23-65
C1, FM 23-65
Table 1-6 lists the maximum penetration in inches for a ball cartridge
fired from the 45-inch barrel (muzzle velocity, 2,935 feet per second):
INCHES AT:
200 600 1,500
MATERIAL METERS | METERS | METERS
Sand (100 pounds dry weight/cubic feet) 14.0 12.0 6.0
Clay (100 pounds dry weight/cubic feet) 21.0
Concrete 1.0
Table 1-6. Maximum penetration for ball cartridge.
1-20
СНАРТЕН 2
MAINTENANCE
This chapter addresses the proper care of the machine gun to
ensure its overall effectiveness and efficient functioning. The
information includes the gunner's knowledge in disassembly
and assembly, inspection, and maintenance procedures of the
gun, its mount, the T&E, and its ammunition.
2-1. SAFETY
The paramount consideration while training with the machine gun is
safety. It is imperative that the weapon be cleared properly before
disassembly and inspection. (See Figure 2-1 for step-by-step procedures.)
1. Unlock the bolt-latch release and raise
the cover.
2. Pull the bolt to the rear. Examine the
chamber and the T-siot to ensure that
they hold no rounds.
3. Place a wooden block inside the receiver
between the bolt and the rear of the barrel.
BOLT-LATCH
BUFFER TUBE (DW BOLT-LATCH
SLEEVE RELEASE LOCK
. Insert a cleaning rod in the muzzle end of
the barrel until the rod can be seen in the
receiver.
. Remove the rod. The gun is now clear.
CLEARING
BLOCK
Figure 2-1. Clearing the weapon.
2-1
ЕМ
23-65
2-2. GENERAL DISASSEMBLY
The crew operating the MG must be fully familiar with its general
disassembly, which consists of removing the major groups and assemblies
for inspection and cleaning. The eight major groups that must be
disassembled in the following order are barrel group, backplate group,
driving spring rod assembly, bolt group, barrel extension group, barrel
buffer body group, barrel buffer assembly, and receiver
group (Figure 2-2).
BACKPLATE ASSEMBLY (ds,
DRIVING SPRING ROD
ASSEMBLY
BOLT GROUP
BARREL BUFFER
BODY GROUP
Figure 2-2. Major groups.
a. Barrel Group. Turn the cover latch and raise the cover group
(Figure 2-3). Grasp the retracting slide handle with the right hand, palm
up, and pull the recoiling parts to the rear until the lug on the barrel
locking spring aligns with the 3/8-inch hole in the right sideplate of the
receiver (just below the feedway exit). The barrel can be turned only
when the lug is aligned with the 3/8-inch hole. Place the smallest loop of a
caliber .50 link, or suitable spacer, between the trunnion block and the
barrel extension (Figure 2-4)| This holds the barrel locking spring lug
aligned with the 3/8-inch hole in the right sideplate. Unscrew the barrel
from the receiver (Figure 2-5,|page 2-4). Be careful not to damage the
threads or barrel locking notches when setting the barrel down. Pull back
slightly on the retracting slide handle and remove the link or spacer from
the receiver.
COVER GROUP
SMALLEST LOOP , Hoa
CAL. .50 LINK
EXTRACTOR
PALM UP
BARREL LOCKING SPRING
INCH HOLE
Figure 2-4. Aligning the lug on the barrel locking spring with the
3/8-inch hole in the right sideplate.
2-3
Figure 2-5. Removing the barrel.
b. Backplate Group. Ensure that the bolt latch release is up, free of
the bolt latch release lock. If it is not, push down on the bolt latch release
and turn the buffer tube sleeve to the right to free it (Figure 2-6). The bolt
must be forward before the backplate is removed. If the bolt is to the rear,
push down on the bolt latch release, place palm up on the retracting slide
handle, and ease the bolt forward. The backplate latch lock and latch are
below the buffer tube. Pull out on the lock and up on the latch; remove
the backplate by lifting it straight up [Figure 2-7).
BOLT LATCH
RELEASE
TRIGGER
BOLT LATCH
RELEASE LOCK
BUFFER TUBE
SLEEVE
Figure 2-6. Releasing the bolt latch.
CAUTION
Care must be taken to prevent the bolt from slamming forward with the barrel
removed.
BACKPLATE LATCH LOCK
Je
BACKPLATE LATCH
(ЛДЫ
Figure 2-7. Removing the backplate.
c. Driving Spring Rod Assembly. The inner and outer driving springs
and driving spring rod are located inside the receiver next to the right
sideplate page 2-6). Push in on the head of the driving spring
rod and push to the left to remove the driving spring rod retaining pin
from its seat in the right sideplate. Pull the driving spring assembly to the
rear and out of the receiver.
WARNING
Never attempt to cock the gun while the backplate is off and the driving
spring assembly is in place. If the backplate is off and the driving spring
assembly is compressed, the retaining pin on the driving spring rod can slip
from its seat in the sideplate and could cause serious injury to anyone behind
the gun.
FM 23-65
2-5
ЕМ 23-65
DRIVING SPRING
ROD ASSEMBLY
BOLT LATCH
Figure 2-8. Removing the driving spring rod assembly.
d. Bolt Stud. Grasp the retracting slide handle and give it a quick jerk,
freeing the bolt from the barrel extension. Align the collar of the bolt stud
with the clearance hole in the bolt slot on the right sideplate, and remove
the bolt stud (Figure 2-9). If the bolt is accidentally moved all the way to
the rear, the bolt latch will engage in the bolt latch notches in the top of
the bolt. If this occurs, raise the bolt latch (left of the trigger lever) and
push the bolt forward to align the bolt stud with the clearance hole
(Figure 2-10).
BOLT STUD
rr rury dran
o о о а
TL oe
SHOULDER SS Е ccc", Yam
d
„чт >
асы О у __
уз е
CLEARANCE
Arc yo
“2
Figure 2-9. Removing the bolt stud.
ЕМ 23-65
BOLT LATCH
TRIGGER LEVER
Figure 2-10. Freeing the bolt.
e. Bolt Group. After freeing the bolt, slide it to the rear and out of
receiver (Figure 2-11). Place the bolt down on its right side (with the
extractor arm up), so that the extractor will not fall from the bolt.
Figure 2-11. Removing the bolt from the receiver.
2-7
ЕМ 23-65
f. Barrel Buffer Body Group and Barrel Extension Group. Insert the
drift of a combination tool, or other pointed instrument, through the hole
in the lower rear corner of the right sideplate. Push in on the barrel buffer
body lock. At the same time, place one hand in the receiver and push the
barrel extension group and barrel buffer group to the rear (Figure 2-12).
Remove the barrel buffer group and barrel extension group from the
receiver. Separate the two groups by pushing forward on the tips of the
accelerator (Figure 2-13).
Figure 2-12. Removing barrel buffer group and
barrel extension group.
ACCELERATOR TIPS
BARREL EXTENSION GROUP
BARREL BUFFER
BODY GROUP
Figure 2-13. Separating the groups.
ЕМ 23-65
g. Barrel Buffer Assembly. Pull the barrel buffer assembly from the
rear of the barrel buffer body group. The barrel buffer assembly will not
be disassembled (Figure 2-14). This completes general disassembly.
BARREL BUFFER ASSEMBLY
CROSS GROOVE IN THE BARREL BUFFER BODY GROUP
PISTON ROD
Figure 2-14. Separating the barrel buffer assembly
from the barrel buffer body group.
2-3. CLEANING, INSPECTION, AND LUBRICATION
To ensure proper care of the MG, it is necessary to have a system of
maintenance or an SOP for the frequency of cleaning. Each gun should be
cleaned as soon after firing as possible and each time it is exposed to field
conditions. Under combat conditions, the gun should be cleaned and oiled
daily. Under extreme climatic and combat conditions, it maybe necessary
to clean and lubricate more frequently. Under ideal conditions, where the
gun is not used, and is stored in a clean, dry place, it may only be necessary
to inspect, clean, and lubricate every 5 days. The gun should be
disassembled, cleaned, and oiled in a clean, dry location. If possible, keep
the gun covered with a gun cover, canvas, tarpaulin, or poncho when not in
use.
a. Routine Care and Cleaning. Before firing (when the situation
permits), take the following steps to ensure efficient functioning of the
machine gun:
* Disassemble the gun into its major groups or assemblies.
* Clean the bore and chamber, and lightly oil them.
e Clean all metal parts thoroughly with CLP. See} paragraph 2-3f |for
lubrication procedures.
2-9
ЕМ 23-65
2-10
b. Care and Cleaning Under Unusual Conditions. Extreme cold, hot,
dry, and tropical climates affect the gun and its functioning. Care should
be taken under these climatic conditions to ensure that the gun is cleaned
daily with the prescribed lubricants and protected from the elements by
some sort of cover if possible. Further information on care and cleaning of
the gun under unusual climatic conditions can be found in
TM 9-1005-213-10.
c. Care and Cleaning of M3 Mount and Accessories. The mount and
accessories, such as the ammunition chest and spare parts, should also be
kept clean and lubricated. Painted surfaces should be spot painted when
necessary. Moving surfaces should be inspected and oiled with the
prescribed lubricant. АП external surfaces of the mount should be kept
clean and lightly oiled. Be particularly careful that the pintle bushing is
clean and lightly oiled, and that the pintle lock release cam is
well-lubricated and free from grit. The sleeve lock indexing levers and
telescopic legs should be clean and lubricated enough for ease in use. The
mount should be cleaned and oiled with the same regularity and in the
same manner as the gun.
d. Maintenance and Inspection. Units must establish guidelines and
conduct regular maintenance and inspection to keep the machine gun and
its mounts in operational conditions.
(1) Gun maintenance. The importance of a thorough knowledge of
care, cleaning, and maintenance of the machine gun cannot be
overemphasized because these actions determine whether or not the gun
will function properly when needed. The bore and chamber must be
properly maintained to preserve accuracy. Because of the close fit of
working surfaces and the high speed at which the gun operates, the
receiver and moving parts must be kept clean, correctly lubricated, and
free from burrs, rust, dirt, or grease to ensure proper, efficient functioning.
(2) Mount maintenance. The care, cleaning, lubrication, and
adjustment of the mounts used with the gun are no less important. The
functioning of the gun and mount together determine overall
effectiveness. All accessories and equipment used with the gun and mount,
including ammunition, must also be properly maintained.
(3) Inspection. When inspected, the machine gun should be
completely disassembled. Inspecting personnel should look for dirt,
cracks, burrs, and rust.
e. Inspection Checklist.[ Table 2-1]is an inspection checklist to be used
as a guide for crewmembers or inspecting personnel to ensure that the gun
and equipment are properly maintained.
ЕМ 23-65
UNIT INSPECTION
1. GUN.
a. Barrel.
Inspect the bore and chamber for rust. See that they are
clean and lightly oiled.
See that they are clean and lightly oiled. Operate the
retracting slide handle and bolt latch release several times
to see that the parts function without excessive friction.
Check with the gauges to ensure that headspace and
timing are correct.
Ensure that the sight is in good condition, clean, free of
grease or dirt, and lightly oiled. Elevation should be set at
1,000, windage zero, and the sight should be down.
b. Moving parts.
c. Headspace and timing.
d. Rear sight and windage knob.
2. MOUNT (M3, MK64, M36, or M4). See that it is clean, lightly lubricated, and that all clamps
are securely tightened. It should function properly and be
complete.
3. SPARE PARTS AND TOOLS. nspect to see that they are clean and lightly oiled. See that
spare parts kits are complete and in good condition.
Replacement parts should be requisitioned and newly
drawn parts examined.
4. T&E. ee that it is clean, lightly lubricated, and that both hand
_ wheels work properly.
5. AMMUNITION. See that ammunition is properly stored, and that boxes and
ammunition are in good condition and not oiled.
Table 2-1. Inspection checklist.
f. Lubrications. Use cleaner, lubricant, preservative to clean the
machine gun. As its name implies, it cleans, lubricates, and preserves all in
one application.
(1) After cleaning the gun with CLP, wipe it dry and reapply a thin
coating. Allow this thin coat to dry on the parts for a short time before
reassembly. CLP deposits a thin coating on the metal which minimizes
carbon buildup and prevents foreign material from sticking. It is this
coating that provides the frictionless operation of the weapon parts, not
liquid oil deposited on them. A gun treated with CLP will operate better
and remain clean longer than one treated with any other cleaning
material. Use of CLP will reduce maintenance costs and extend the life of
the weapon.
(2) Rifle bore cleaner is a cleaning solvent which can be used to clean
powder residue, carbon, and dirt from weapons. RBC does not preserve or
lubricate a weapon. If you clean a weapon with RBC, dry the weapon and
lubricate it with lubricating oil, semifluid (LSA); lubricating oil, special
purpose (PL-S); or lubricating oil, general purpose (PL-M). The use of
these oils will cause sand or grit to stick to the weapon. RBC and oil
should be used only when CLP is not available.
2-11
ЕМ 23-65
2-4. MAINTENANCE PROCEDURES
There are certain actions that must be taken before, during, and after
firing to properly maintain the gun. See Table 2-2 for a preoperation
checklist.
DURING FIRING
OR TEMPORARY
CESSATION
PART BEFORE
АЛл 1, л cura it ie блем
маде DUIG Ii тә vica
and clean.
Moving parts | Oil lightly and test for Lubricate working parts. Inspect, clean, and oil
worn or broken parts. Observe the functioning lightly.
They should function of the gun to anticipate
without excessive failures.
friction.
Headspace Check adjustment by Watch for bulged cases Check adjustment.
and timing gauge and correct if to prevent a ruptured
necessary. (separated) case. If a
eaneratad nann Arnfiire
эсраға:си Vast мш ә,
remove it and readjust
headspace.
Rear sight See that the sight is Keep properly set. Clean and oil; set at
and windage clean and functions 1,000, windage zero.
knob properly. Set sight at
1,000, windage zero.
Spare parts Clean and oil spare parts| Keep available. Clean and oil. Check
and tools and tools. Check kits for and replace damaged
completeness. Examine or missing parts.
newly drawn parts.
Ammunition Have an adequate Keep correctly aligned Clean, store carefully,
supply; clean, correctly with the feedway; check and replenish supply.
loaded, and in good resupply. Protect from
condition. DO NOT OIL. sun, moisture, and dirt.
Watch for link stoppage.
Table 2-2. Operational checklist.
2-5. MAINTENANCE UNDER NBC CONDITIONS
If contamination is anticipated, apply oil to all outer metal surfaces of the
weapon. DO NOT OIL AMMUNITION. Keep the weapon covered as
much as possible. If the weapon is contaminated, decontaminate it as
prescribed by FM 3-5 and then clean and lubricate it.
2-6. GENERAL ASSEMBLY
To assemble the gun, replace the groups and assemblies in reverse order
of their removal in disassembly.
2-12
ЕМ 23-
a. Barrel Buffer Assembly and Barrel Buffer Body Group. Replace
the barrel buffer assembly in the barrel buffer body group, with the key on
the spring guide to the right. This key must fit in its slot in the right side of
the barrel buffer body. Turn the barrel buffer tube until the screwdriver
slot (in the rear of the tube) is vertical and the arrow is pointing to the
right. The stud on the tube lock will now engage the serrations in the
barrel buffer tube to keep the tube from turning. Push the barrel buffer
assembly fully forward (Figures 2- 15 and 2-16).
BARREL BUFFER BODY
SPRING LOCK
BARREL BUFFER GUIDE BARREL BUFFER SPRING
GUIDE KEY
SERRATIONS
Figure 2-16. Replacing the barrel buffer tube.
ЕМ 23-65
b. Barrel Buffer Group and Barrel Extension Group. To join the two
groups together, hold the barrel buffer group in the right hand, with the
index finger supporting the accelerator. Join the notch on the shank of the
barrel extension group with the cross-groove in the pistol rod of the barrel
buffer assembly. At the same time, align the breech lock depressors with
their guideways in the sides of the barrel extension, ensuring that the tips
of the accelerator are against the rear end of the barrel extension (claws
against the shank) (Figure 2-17). Push the groups together. As the
accelerator rotates to the rear, press down on its tips to ensure positive
locking of groups. Place the groups in the receiver, and push them forward
until the barrel buffer body spring lock snaps into position. When the parts
are properly locked in place, the barrel buffer tube should protrude about
] 1/8 inches from the rear of the barrel buffer body group.
c. Bolt. Place the bolt in the receiver, with the top of the cocking lever
forward and the extractor down. The barrel extension, barrel buffer, and
bolt groups may be assembled and returned to the receiver together
Figure 2-18).
BARREL EXTENSION ACCELERATOR
TIP
SHANK
BREACH LOCK
DEPRESSOR
ACCELERATOR CLAWS
GUIDEWAY
Figure 2-17. Joining the barreí extension
group and barrel buffer group.
2-14
*
C1, ЕМ 23-65
BOLT SWITCH MECHANISM
Ja LEFT-HANDED FEED
* Figure 2-18. Returning the barrel extension, barrel buffer,
and bolt groups together.
* CAUTION
Before inserting the bolt group, ensure bolt switch mechanism is
positioned on L (left-hand) feed for the weapon.
d. Bolt Stud. Align the stud hole in the bolt with the clearance hole
and replace the bolt stud, ensuring that the collar of the stud is inside the
sideplate (Figure 2-19).
* Figure 2-19. Replacing the bolt stud.
e. Drive Spring Assembly. Press up on the bolt latch and push the
bolt all the way forward by pushing on the bolt stud only. Place the end of
the drive spring rod in its hole in the rear of the bolt, and push forward on
the drive spring assembly and the barrel buffer tube. Press in and to the
right on the head of the drive spring rod and place the retaining pin in its
seat in the right sideplate (Figure 2-20).
C1, FM 23-65
*
Figure 2-20. Inserting drive spring and drive spring rod
(with drive spring rod inside drive spring).
* NOTE: Atthis time, the barrel buffer tube should be completely inside
the receiver. If not, the barrel buffer body spring is not properly
seated.
f. Backplate Group. Hold the backplate with the latch down and the
trigger up; place the backplate guides in their guideways. Hold out on the
latch lock and tap the backplate into position until the latch snaps into
place (Figure 2-21). Release the latch lock and pull up on the backplate
group to ensure it is firmly seated.
* Figure 2-21. Replacing the backplate group.
2-16
* CAUTION
Do not use the driving rod to drive the bolt forward from the
rear position. This may damage the drive spring group and
cause a stoppage.
g. Barrel. Pull the retracting slide handle to the rear until the lug on
the barrel locking spring is visible through the 3/8-inch hole in the right
sideplate. Place the smallest loop of a caliber .50 link, or suitable spacer,
between the trunnion block and the barrel extension. Screw the barrel all
the way into the barrel extension; then unscrew the barrel two notches.
Remove the link and close the cover. This completes general assembly.
2-7. FUNCTION CHECK
A function check must be performed as soon as the weapon is assembled
to ensure that the weapon has been assembled correctly. The following
procedures should be taken to check the function of the weapon.
a. Place the weapon in the single-shot mode.
b. Open the cover and lock the bolt to the rear (bolt should stay to
rear while in the single-shot mode).
c. Hold the retractor handles, press the bolt latch release, and ride the
bolt forward.
d. Press down on the trigger; weapon should fire. (Check T-slot to
ensure that firing pin does protrude.)
e. Placethe weapon in the automatic-fire mode
f. Pull the retractor slide handle to the rear and hold. (Bolt should
not lock to rear.)
g. Release the pressure on the slide handles and ride the bolt forward
h. Make sure firing pin does not protrude
i. Press trigger; weapon should fire
j. Make sure firing pin does protrude.
NOTE: Before firing a newly assembled weapon, first set the
headspace and timing. Chapter 3 describes these procedures.
C1, FM 23-65
C1, FM 23-65
* CHAPTER 3
OPERATION AND FUNCTIONING
This chapter explains the operation of the MG. It
discusses the loading, unloading, and clearing procedures,
and the cycle of functioning of the weapon. When training
the cycle of functioning using dummy ammunition, it is
imperative that all safety procedures be followed.
* 3-1. OPERATION
The overall operation of the MG includes how to load, unload, and clear
the weapon. During the weapon's operation, it is mandatory that all
ammunition be free of dirt and corrosion, that the ammunition be properly
linked, and that the double-linked end be at the top of the ammunition can.
* 3-2. LOADING PROCEDURES
Trainers must ensure that the weapon functions correctly and that proper
headspace and timing have been set before loading. When loading in
either mode, the ammunition is fed into the MG in the same manner
(Figure 3-1). Ensure that the bolt is forward and the cover is closed. Insert
the double-loop end of the ammunition belt into the feedway until the first
round is engaged by the belt-holding pawl. Figure 3-2 shows the correct
position of the bolt latch in the single-shot or automatic mode.
ao
QN SS È
Кул
ПА
М УУ
&
Се
SPS PY
AS NOS
> (Dy
al
7 АА
Figure 3-1. Inserting ammunition.
3-1
C1, FM 23-65
a. Single-Shot Mode. When engaging targets at ranges greater than
1,100 meters, using the single-shot mode (firing one round at a time)
allows the gunner to deliver well-aimed fire on the target. To load in the
single-shot mode--
(1) Keep the bolt-latch release unlocked in the up position and
release it manually for each round.
(2) Jerk the retracting slide handle to the rear and lock it in
position. Return the retracting slide handle to the forward position and
then release the bolt by pressing the bolt latch release. The gun is now
half-loaded.
(3) To complete loading, jerk the retracling-stide-inindle to the
rear and lock it in position. Return the retracting slide handle to the
forward position. Press the bolt latch release. When the bolt goes forward
for the second time, the gun is loaded.
b. Automatic Mode. To load in the automatic mode--
(1) Lock the bolt-latch release down with the bolt- latch
release lock.
(2) Jerk the retracting slide handle to the rear and release it. The
gun is now half-loaded.
(3) To complete loading, jerk the retracting slide handle to the
rear a second time and release it. When the bolt goes forward for the
second time, the gun is loaded.
BOLT-LATCH RELEASE BOLT-LATCH
LOCKED DOWN RELEASED
AUTOMATIC MODE SINGLE-SHOT MODE
Figure 3-2. Firing modes.
* 3-3. UNLOADING PROCEDURES
To unload the MG, the gunner must first ensure that the weapon is in the
single-shot mode. The cover is then lifted and the assistant gunner
removes the ammunition belt from the feedway. The bolt is then locked to
the rear. If a round is chambered, it will release, unfired, when the bolt
locks to the rear. Once the bolt is locked to the rear, the chamber and
T-slot are examined to ensure that they are not holding rounds. In
darkness, this must be done by feeling the areas. After the examination has
been done (during training), a wooden block is inserted in the receiver
between the bolt and the rear of the barrel, extending above and below the
receiver about one inch. Then a cleaning rod is inserted in the muzzle end
of the barrel and pushed through the bore until it can be seen in the
receiver. Remove the rod, the gun is now clear (Figure 3-3).
CLEANING ROD
CLEARING BLOCK
Figure 3-3. The clearing block.
* 3-4. CYCLE OF FUNCTIONING
The cycle of functioning is broken down into basic steps: feeding,
chambering, locking, firing, unlocking, extracting, ejecting, and cocking.
Some of these steps may occur at the same time.
a. Feeding. Feeding is the act of placing a cartridge in the receiver,
approximately in back of the barrel, ready for chambering. When the bolt
is fully forward and the top is closed, the ammunition belt is held in the
feedway by the belt-holding pawl (Figure 3-4).
(1) As the bolt is moved to the rear, the belted ammunition is moved
over and then held in a stationary position by the belt-holding pawl. At the
same time, the belt-feed pawl rides up and over the link, holding the first
round in place. When the bolt is all the way to the rear, the belt-feed slide
moves out far enough to allow the belt-feed pawl spring to force the pawl
up between the first and second rounds (Figure 3-5).
C1, FM 23-65
3-3
C1, FM 23-65
BELT FEED SLIDE
BELT FEED PAWL
BELT-HOLDING PAWL
Figure 3-4. Feeding--step 1.
BELT FEED SLIDE
BELT FEED PAWL
Figure 3-5. Feeding--step 2.
EM 23-65
(2) As the bolt moves forward, the belt-feed slide is moved back into
the receiver, pulling with it the next linked cartridge. When the bolt
reaches the fully forward position, the belt-holding pawl will snap into
place behind the second linked cartridge (Figure 3-7), holding it in place.
The extractor will then grasp the rim of the first cartridge, preparing to
release it from the belt on the next rearward motion (Figure 3-8).
BELT HOLDING PAWL
BELT FEED PAWL
CHAMBER
Figure 3-8. Feeding — withdrawing the first roun e feedway.
(3) As the bolt then moves to the rear, the extractor will pull the
cartridge with it, releasing it from the belt. As it moves to the rear, the
extractor is forced down by the extractor cam, causing the cartridge to be
moved into the T-slot in the bolt face, preparing the cartridge to be
chambered page 3-6). It is connected under the extractor
switch on the side of the receiver until it is repositioned by the forward
movement of the bolt, and pressure of the cover extractor spring forces it
over the next round.
3-5
ЕМ 23-65
EXTRACTOR
BASE OF CARTRIDGE
ENTERING T-SLOT
Figure 3-9. Feeding - cartridge entering the T-slot in the bolt.
b. Cambering. Cambering is placing the cartridge into the chamber
of the weapon. During this cycle, the bolt moves forward, carrying the
cartridge in the T-slot in a direct route to the chamber of the weapon. At
the same time, the extractor rides up the extractor cam and when the bolt
is fully forward, the extractor grasps the next linked cartridge
(Figure 3-10).
COVER EXTRACTOR SPRING EXTRACTOR SWITCH EXTRACTOR CAM
c. Locking. The bolt is locked to the barrel and barrel extension.
(1) Initially, the bolt is forced forward in counter-recoil by the energy
stored in the driving spring assembly and the compressed buffer disks. At
the start of counter-recoil, the barrel buffer body tube lock keeps the
accelerator tips from bounding up too soon and catching in the breech
lock recess in the bolt. After the bolt travels forward about 5 inches, the
lower rear projection of the bolt strikes the tips of the accelerator, turning
the accelerator forward. This unlocks the barrel extension from the barrel
buffer body group and releases the barrel buffer spring. The barrel buffer
spring expands, forcing the piston rod forward.
3-6
ЕМ 23-65
(2) Since the cross groove in the piston rod engages the notch on the
barrel extension shank, the barrel extension and barrel are also forced
forward by the action of the barrel buffer spring. Some of the forward
motion of the bolt is transmitted to the barrel extension through the
accelerator. As the accelerator rotates forward, the front of the
accelerator speeds up the barrel extension; at the same time, the
accelerator tips slow down the bolt.
(3) Locking begins 1 1/8 inches before the recoiling groups (bolt,
barrel extension, and barrel) are fully forward. The breech lock in the
barrel extension rides up the breech lock cam in the bottom of the
receiver into the breech lock recess in the bottom of the bolt, locking the
recoiling groups together. The recoiling groups are completely locked
together three-fourths of an inch before the groups are fully forward
(Figure 3-11).
WRIA
ACCELERATOR
BREECH
LOCK
BARREL
EXTENSION
BREECH
LOCK
— CAM
Figure 3-11. Locking — recoiling groups locked together.
d. Firing. The firing pin is released, igniting the primer of the
cartridge.
(1) As the trigger impressed down, it pivots on the trigger pin, so that
the trigger cam on the inside of the backplate engages and raises the rear
end of the trigger lever. This in turn pivots on the trigger lever pin
assembly, causing the front end of the trigger lever to press down on the
top of the sear stud. The sear is forced down until the hooked notch of the
firing pin extension is disengaged from the sear notch. The firing pin and
firing pin extension are driven forward by the firing pin spring; the striker
of the pin hits the primer of the cartridge, firing the round
3-
(Figures |3-12 and| 3-13, раге 3-8).
3-7
ЕМ 23-65
LEVER FIRING PIN SPRING CARTRIDGE
TRIGGER TRIGGER LEVER PIN TRIGGER LEVER FIRING PN EXTENSION
FIRING PIN SPRING FIRING PIN
Figure 3-13. Firing — round ignited.
(2) For automatic firing, the bolt-latch release must be locked or held
depressed, so that the bolt latch will not engage the notches in top of the
bolt, holding the bolt to the rear as in single-shot firing. The trigger is
pressed and held down. Each time the bolt travels forward in
counter-recoil, the trigger lever depresses the sear, releasing the firing pin
extension assembly and the firing pin. This automatically fires the next
round when the forward movement of the recoiling groups is nearly
completed. The gun should fire about one-sixteenth of an inch before the
recoiling groups are fully forward. Only the first round should be fired
with the parts fully forward. The gun fires automatically as long as the
trigger and bolt latch are held down and ammunition is fed into the gun.
e. Unlocking. The bolt is unlocked from the barrel and barrel
extension.
(1) At the instant of firing, the bolt is locked to the barrel extension
and against the rear end of the barrel by the breech lock, which is on top
3-8
ЕМ 23-65
of the breech lock cam and in the breech lock recess in the bottom of the
bolt. When the cartridge explodes, the bullet travels out of the barrel; the
force of recoil drives the recoiling groups rearward. During the first
three-fourths of an inch, the recoiling groups are locked together. As this
movement takes place, the breech lock is moved off the breech lock cam
stop, allowing the breech lock depressors (acting on the breech lock pin)
to force the breech lock down, out of its recess from the bottom of the
bolt. At the end of the first three-fourths of an inch of recoil, the bolt is
unlocked, free to move to the rear independent of the barrel and barrel
extension.
(2) As the recoiling groups move to the rear, the barrel extension
causes the tips of the accelerator to rotate rearward. The accelerator tips
strike the lower rear projection of the bolt, accelerating the movement of
the bolt to the rear. The barrel and barrel extension continue to travel to
the rear an additional three-eighths of an inch, or an approximate total
distance of 1 1/8 inches until they are stopped by the barrel buffer
assembly (Figure 3-14).
BARREL BUFFER ASSEMBLY
BARREL EXTENSION BARREL
Figure 3-14. Unlocking — barrel and barrel extension stopped by
the barrel buffer assembly.
(3) During the recoil of 1 1/8 inches, the barrel buffer spring is
compressed by the barrel extension shank, since the notch on the shank is
engaged in the cross groove in the piston rod head. The spring is locked in
the compressed position by the claws of the accelerator, which engage the
shoulders of the barrel extension shank. After its initial travel of
three-fourths of an inch, the bolt travels an additional 6 3/8 inches to the
rear, after it is unlocked from the barrel and barrel extension, for a total of
3-9
ЕМ 23-65
7 1/8 inches. During this movement, the driving springs are compressed.
The rearward movement of the bolt is stopped as the bolt strikes the
buffer plate. Part of the recoil energy of the bolt is stored by the driving
spring rod assembly, and part is absorbed by the buffer disks in the
backplate (Figure 3-15).
BUFFER PLATE
Figure 3-15. Unlocking — recoil movement completed.
f. Extracting. The empty cartridge case is pulled from the chamber.
(1) The empty case, held by the T-slot, has been expanded by the
force of the explosion; therefore, it fits snugly in the chamber. If the case is
withdrawn from the chamber too rapidly, it may be torn. To prevent this,
and to ensure slow initial extraction of the case, the top forward edge of
the breech lock and the forward edge of the lock recess in the bolt are
beveled. As the breech lock is unlocked, the initial movement of the bolt
away from the barrel and barrel extension is gradual.
(2) The slope of the locking faces facilitates locking and unlocking and
prevents sticking. The leverage of the accelerator tips on the bolt speeds
extraction after it is started by kicking the bolt to the rear to extract the
empty case from the chamber.
g. Ejecting. The empty cartridge case is expelled from the receiver.
(1) As the bolt starts its forward movement (counter-recoil), the
extractor lug rides below the extractor switch, forcing the extractor
assembly farther down until the round is in the center of the T-slot of the
bolt.
(2) The round, still gripped by the extractor, ejects the empty case
from the T-slot. The last empty case of an ammunition belt is pushed out
by the ejector.
ЕМ 23-65
h. Cocking. The firing pin is withdrawn into the cocked position.
(1) When the recoiling groups are fully forward, the top of the cocking
lever rests on the rear half of the V-slot in the top plate bracket. As the
bolt moves to the rear, the top of the cocking lever is forced forward. The
lower end pivots to the rear on the cocking lever pin. The rounded nose of
the cocking lever, which fits through the slot in the firing pin extension,
forces the extension to the rear, compressing the firing pin spring against
the sear stop pin (accelerator stop). As the firing pin extension is pressed
to the rear, the hooked notch of the extension rides over the sear notch,
forcing the sear down. The sear spring forces the sear back up after the
hooked notch of the firing pin extension has entered the sear notch.
(2) The pressure of the sear and firing pin springs holds the two
notches locked together. There is a slight overtravel of the firing pin
extension in its movement to the rear to ensure proper engagement with
the sear. As the bolt starts forward, the overtravel is taken up and
completed when the cocking lever enters the V-slot of the top plate
bracket, and is caromed toward the rear; pressure on the cocking lever is
relieved as the bolt starts forward.
3-5. LEFT-HAND FEED
By repositioning some of the components, the MG is capable of alternate
feed. Ammunition can be fed into the weapon from the right or left side of
the receiver; however the Army uses only left-hand feed. (See Table 3-1).
PART POSITION
. Beit-feed lever, shoulder headless | Upper (rear) hole; lug of feed lever is on
pin, and spring. left side of cover.
Belt-feed slide. ў Feed pawl is on left side of cover.
Belt-feed pawl arm. Arm toward latch end of cover, pointing right. —
Cover latch shaft lever Left side of cover. ee En]
Cartridge stops and link stripper. Right-hand rear cartridge stop assembly and front |
.Retracting slide with handle.
_ Belt-holding pawl. Left side of feedway. -
Bolt switch. Cam grove in line with "L" on bolt.
Table 3-1. Position of parts for left-hand feed.
DANGER
Clear the gun of ammunition before setting headspace.
о фії
ЕМ 23-65
3-6. HEADSPACE AND TIMING
Headspace is the distance between the face of the bolt and the base of the
cartridge case, fully seated in the chamber. Timing is the adjustment of the
gun so that firing takes place when the recoiling parts are in the correct
position for firing. Because the cartridge is held by the T-slot of the bolt,
headspace with the MG is measured as the distance between the rear of
the barrel and the face of the bolt. This occurs when the recoiling parts are
forward and there is positive contact between the breech lock recess in the
bolt and the lock in the barrel extensions. Periodic calibration checks
should be made of the gauge by direct support personnel at least annually.
WARNING
Firing a weapon that has improperly set headspace and timing could result in
damage to the machine gun, or injury to the gunner. Damage may also occur
in the trunnion block, base of the barrel, or face of the bolt. This warning
applies whether the gun is firing service ammunition or M1E1 blanks. (The
weapon has improper early timing when two rounds are fired — and firing
stops.)
a. Gauges. The headspace and timing gauge consists of a headspace
gauge and two timing gauges (Figure 3-16). These gauges provide an
accurate means of checking the adjustment of headspace and timing.
NOTE: The headspace and timing gauge should be kept
with the gun at all times.
Figure 3-16. Headspace and timing gauge.
b. Headspace. Check and set headspace before firing, after assembling
the gun, and after replacing the barrel or receiver group. Use the
following procedures to set headspace.
(1) Raise the cover all the way up. Grasp the retracting slide handle
(Figure 3-17). Using the retracting slide handle, retract the bolt until the
barrel-locking-spring lug is centered in the 3/8-inch hole on the right side
of the receiver [Figure 3-18).
ЕМ 23-65
3/8 INCH HOLE
IN RECEIVER
Figure 3-18. Retracting the bolt.
(2) Hold the bolt in this position and screw the barrel fully into the
barrel extension (Figure 3-19).
Figure 3-19. Screwing in the barrel.
ЕМ 23-65
WARNING
When resetting the headspace and timing of a gun that
has been fired, use an asbestos mitt to avoid burns.
(3) With the bolt still retracted, unscrew the barrel two notches
(clicks). Release the retracting slide handle and allow the bolt to go
forward.
NOTE: At this point, check the barrel for rotation. Attempt to
turn the barrel in either direction. The barrel should not turn.
If the barrel does turn, stop here and check barrel notches
and the barrel-locking spring for damage.
(4) Pull the bolt to the rear with the retracting slide handle and hold.
This cocks the weapon. Otherwise, the headspace gauge will not fit.
(5) Holding the retracting slide handle, release the bolt, and slowly
return the bolt fully forward (Figure 3-20). Do not press the trigger or let
the bolt slam forward.
Figure 3-20. Releasing the bolt.
3-14
ЕМ 23-65
(6) Retract the retracting slide handle and separate the barrel
extension from the trunnion block by a 1/16-inch gap (Figure 3-21).
Pe ue | | еа
TRUNNION
BLOCK
BARREL EXTENSION
Figure 3-21. Setting the gap.
(7) Raise the extractor out of the way to clear the top of the T-slot and
try both ends of the go/no-go gauge as shown in Figure 3-22.
NOTE: Insert the go end of the gauge between the face of the bolt and
the end of the barrel all the way up to the ring.
EXTRACTOR
"GO" END
N
END OF BARREL
Figure 3-22. Using the gauge.
ЕМ 23-65
3-16
(8) If the go end of the gauge enters the T-slot freely to the center ring
of the gauge, and the no-go end will not enter, headspace is correct.
Remove gauge. Headspace setting is now complete. If the go end of the
gauge will not enter the T-slot freely, headspace is too tight. Continue as
follows.
(9) Retract the bolt so you can see the barrel-locking lug in the center
of the 3/8th-inch alignment hole on the right side of the receiver.
(10) Unscrew the barrel one notch (click).
(11) Return the bolt fully forward.
(12) Recheck headspace (step 9).
(13) Repeat steps 10 through 13 until the go gauge fits but the no-go
gauge does not fit.
NOTE: You should not have to unscrew the barrel more than five
notches (clicks) beyond the first setting of two clicks. If this
condition does occur, turn in the machine gun to your unit
armorer for inspection.
(14) If the no-go end of the gauge enters the T-slot, headspace is too
loose. Adjust it using the same procedures as above, screwing the barrel
into the barrel extension rather than out.
(15) Repeat steps 10 through 13, one click at a time, until the no-go
gauge does not fit but the go gauge does fit.
c. Timing. Timing is the adjustment of the weapon so that firing takes
place when the recoiling parts are between .020 and .116 inch out of
battery to prevent contact between the front end of the barrel extension
and the trunnion block. Use the following procedures to set timing.
WARNING
Make sure the gun is clear of ammunition before starting.
(1) Check headspace first as previously described.
(2) Pull the bolt to the rear with the retracting slide handle and then
ease bolt fully forward to cock the machine gun.
(3) Grasp the retracting slide handle and retract the bolt just enough
(1/16 inch) to insert the no-fire gauge between the barrel extension and
the trunnion block. Release the retracting slide handle KFigure 3-23).
(4) Depress the trigger. Gun should not fire.
Figure 3-23. Inserting the no-fire gauge.
NOTE: Insert timing gauge with bevel against barrel notches.
NOTE: If the gun does not fire, go to step 5. If the gun does fire, you have
early timing. Go on to steps 7 through 14.
(5) Grasp the retracting slide handle and retract the bolt just enough
to remove the no-fire gauge and insert the fire gauge in the same place
(Figure 3-24). Release the retracting slide handle.
ZA 22 : Pw
; 7 Я # a FIRE
e M
Figure 3-24. Inserting the fire gauge.
9
(6) Depress the trigger. Gun should fire. If it does, timing adjustment
is now complete.
NOTE: If the gun does not fire, you have late timing. Go to steps
7 through 14.
(7) Remove the gauge, cock the gun, and return the bolt forward
(8) Insert the fire gauge.
FM 23-65
3-17
ЕМ 23-65
3-18
(9) Remove the backplate.
(10) Screw the timing adjustment nut all the way down until it touches
the trigger lever (Figure 3-25).
Figure 3-25. Adjusting the timing nut.
WARNING
Never cock the gun with the backplate off.
(11) Try to fire the MG by pushing up on the rear of the trigger lever.
Gun should not fire.
(12) Screw the timing adjustment nut up (to the right) one click at a
time. Push up on the trigger lever after each click. Keep doing this until
the gun fires.
(13) Turn the timing adjustment nut no more than two more clicks up
(to the right).
(14) Remove the gauge, replace the backplate, and pull the bolt to the
rear to cock the machine gun. Ease the bolt forward with the charging
handle. Do not allow the bolt to slam forward.
(15) Recheck the timing with the fire/no-fire gauge twice after the
backplate is installed to ensure that the setting is correct.
d. Field Expedient Methods. When a go/no-go gauge is not available,
you can still set the headspace and timing using field expedient methods.
However, this method should be used only in combat.
(1) To set headspace:
(a) Raise the cover and retract the bolt in the normal manner until the
barrel-locking-spring lug is centered in the 3/8-inch hole on the right side
of the receiver.
ЕМ 23-65
(b) Hold the bolt in this position and screw the barrel fully into the
barrel extension; then unscrew the barrel two clicks or notches.
(2) To set timing:
(a) Use a dog tag or a dime as a fire gauge.
(b) Use a nickel and a dime or four dog tags as a no-fire gauge.
(c) Set the timing using the normal procedure.
(3) To check for correct settings:
(a) Attempt to fire the weapon. If it fires sluggishly, clear the weapon
then unscrew the barrel one more notch.
(b) Recheck the rate of fire. Repeat the procedures in paragraph (1);
however, do not exceed two more clicks.
(c) Do not unscrew the barrel more than one notch between test
firings.
CHAPTER 4
PERFORMANCE PROBLEMS AND
DESTRUCTION
This chapter discusses the malfunctions, stoppages, immediate
actions, remedial actions, and destruction procedures of the
MG. All corrective actions must comply with safety
procedures.
4-1. MALFUNCTIONS
A malfunction is any failure of the gun to function satisfactorily. Examples
of malfunctions are:
a. Failure to Function Freely. Sluggish operation is usually due to
human failure to eliminate excessive friction caused by dirt, lack of proper
lubrication, burred parts, incorrect headspace adjustment, or incorrect
timing.
b. Uncontrolled Automatic Fire. Uncontrolled automatic fire
(runaway gun) is when fire continues even when the trigger or trigger
control mechanism is released. If the cause is present before the gun is
fired, the gun will start to fire when the recoiling groups move into battery
the second time. If the defect occurs during firing, the gun will continue
firing when the trigger control mechanism is released. A runaway gun may
be caused —
* By a bent trigger lever, forward end of the trigger lever
sprung downward.
* By burred beveled contacting surfaces of the trigger lever and sear.
* By a jammed or broken sideplate trigger.
To stop the uncontrolled automatic fire:
(1) Keep the gun laid on target.
(2) Twist the belt, causing the gun to jam.
(3) Caution, do not unlatch the cover.
(4) Wait 5 minutes to guard against cook off.
(5) Clear weapon, replace broken, worn, or burred parts. Check the
sideplate trigger and trigger control mechanism, when applicable.
4-2. STOPPAGES
A stoppage is any interruption in the cycle of operation caused by the
faulty action of the gun or ammunition. Stoppages are classified as follows:
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ЕМ 23-65
a. Failure to Feed. Prevents the round from being properly
positioned in the receiver group.
b. Failure to Chamber. Prevents the complete chambering of the
round.
c. Failure to Lock. Prevents the breech lock from correctly entering
its recess in the bolt.
d. Failure to Fire. Prevents the ignition of the round.
e. Failure to Unlock. Prevents the breech lock from moving out of its
recess in the bolt.
f. Failure to Extract. Prevents the extraction of the expended
cartridge from the chamber.
g. Failure to Eject. Prevents the ejection of the expended cartridge
from the receiver.
h. Failure to Cock. Prevents the firing pin extension from being
engaged with the sear.
Table 4-1 lists the causes of most stoppages.
NATURE OF
STOPPAGE
Failure to feed.
Failure to chamber.
Failure to lock
USUAL
CAUSES
Defective ammunition belt.
Defective feed mechanism.
Defective extractor.
Broken part or obstruction in T-slot
or chamber. Separated (ruptured)
case.
incorrect headspace.
OTHER
CAUSES
improperly loaded belt.
Short round
Thick or thin rim, bulged round,
protruding primer.
Broken parts. Battered breach lock.
Battered breach lock cam. Faulty
breech lock cam adjustment.
Failure to fire. Defective parts in firing mechanism.
Defective ammunition. Incorrect
timing.
Failure to unlock. Broken parts in receiver. Worn or faulty breech lock cam, or
faulty adjustment.
Failure to extract. Dirty chamber. Defective cartridge case.
Failure to eject. | Defective ejector. Burred T-slot.
Failure to cock. Broken sear. Worn sear notch. Weak Broken cocking lever.
sear spring. Worn hooked notch on
firing pin extension.
Table 4-1. Stoppages and their causes.
4-3. IMMEDIATE ACTION
The first thing to do when a stoppage occurs is to apply immediate action,
which is the prompt action taken by the firer to reduce a stoppage.
4-2
ЕМ 23-65
Immediate action is performed by the gunner; however, every
crewmember must be trained to apply immediate action. The following
procedures will assist in reducing most stoppages without analyzing their
cause in detail.
WARNING
Failure to follow procedures may result in damage to weapon and
injury to personnel.
a. If gun fails to fire, take the following action:
(1) Wait 5 seconds; a hangfire maybe causing the misfire. In the next
5 seconds, pull the bolt to the rear (check for ejection and feeding of belt),
release it, re-lay on the target, and attempt to fire. If the bolt-latch release
and trigger are depressed at the same time, the bolt goes forward and the
weapon should fire automatically.
(2) If the gun again fails to fire, wait 5 seconds, pull the bolt to the
rear (engage with bolt latch if applicable), and return the retracting slide
handle to its forward position. Open the cover and remove the belted
ammunition. Inspect the gun to determine the cause of stoppage.
b. A hangfire or cookoff can cause injury to personnel or damage to
the weapon. To avoid these, the gunner must take the following
precautions:
(1) Always keep the round locked in the chamber the first 5 seconds
after a misfire occurs. This prevents an explosion outside of the gun in
event of a hangfire.
(2) If the barrel is hot, the round must be extracted within the next 5
seconds to prevent a cookoff. When more than 150 rounds have been fired
in a 2-minute period, the barrel is hot enough to produce a cookoff.
(3) If the barrel is hot and the round cannot be extracted within the 10
seconds, it must remain locked in the chamber for at least 5 minutes, to
guard against a cookoff.
(4) Keep the gun cover closed during the waiting periods.
4-4. REMEDIAL ACTION
When immediate action does not correct the malfunction, the quickest
way to resume firing is to replace the defective part.
a. Removal of a Cartridge from the T-Slot. If the cartridge does not
fall out, hold the bolt to the rear, and with the extractor raised, use a
screwdriver to push the cartridge out the bottom of the receiver.
b. Removal of a Ruptured Cartridge. A ruptured (separated) cartridge
case may be removed with a cleaning rod or ruptured cartridge extractor.
When using the ruptured cartridge extractor, raise the cover and pull the
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bolt to the rear. Place the extractor in the T-slot of the bolt in the same
manners as that of a cartridge, so that it is held in line with the bore by the
ejector of the extractor assembly of the gun. With the extractor aligned
with the bore and held firmly in the T-slot, let the bolt go forward into the
ruptured case, and the shoulders will spring out in front of the case. Pull
the bolt to the rear and remove the ruptured case and extractor
(Figures 4-1 and 4-2).
SHOULDERS
RUPTURED CARTRIDGE
CASE EXTRACTOR
Figure 4-2. Ruptured cartridge case extractor aligned
with the chamber.
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4-5. DESTRUCTION PROCEDURES
The decision to destroy the gun to prevent its capture and use by the
enemy is a command decision. It will be ordered and carried out only on
authority delegated by the major unit commander.
e Destroy the machine gun and mount only when they are subject to
capture or abandonment. Destruction must be as complete as
circumstances permit.
e Lacking time for complete destruction, destroy the parts essential
to operation of the gun, beginning with those parts most difficult
for the enemy to duplicate.
e Destroy the same parts of each gun to prevent the reconstruction
of a complete gun from several damaged guns.
The following methods may be used to destroy specific components of the
MG.
a. Gun. Field strip the gun. Use the barrel as a sledge. Raise the cover
and smash the cover forward and down toward the barrel support. Smash
the backplate group. Remove the firing pin from the bolt; place the striker
in the hole in the face of the bolt and bend it until broken. Remove the
barrel buffer tube lock assembly from the barrel buffer body group and
bend and deform it. Smash and bend the breech lock depressors. Place the
barrel extension in the rear of the receiver with the barrel extension shank
protruding; knock off the shank by striking it with the barrel from the side.
Deform and crack the receiver by striking it with the barrel at the
sideplate corners nearest the feedway. Smash the extractor.
b. Tripod Mount, M3. Leave the pintle on the tripod by removing the
pintle bolt from the gun. Use the barrel as a sledge. Strike the sides of the
pintle and deform it. Fold the trail legs and turn the mount over. Stand on
the folded trail legs and knock off the pintle latch (pintle lock release
cam). Smash the elevating mechanism with the barrel. If possible, smash
the rear legs to prevent unfolding.
c. Antiaircraft Mount, M63. Remove the sideplate trigger control
mechanism from its container or the gun, and deform it by using the
barrel. Lock the cradle and yoke assembly in the horizontal position and
beat the trigger frame assembly and cradle until they are bent down along
the elevator assembly. Strike the elevator from the side with the barrel
until it is bent so that the elevator will not rotate in the base.
d. Spare Parts. Destroy the bolt, barrel extension, firing pins, and
barrel buffer groups. Break or deform all other parts.
e. Ammunition. When time permits and material is available, destroy
ammunition by burning. Unpack all ammunition from boxes or cartons,
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4-6
stack the ammunition in a heap and, using flammable material available,
ignite and take cover immediately.
f. Burning. To destroy the gun by burning, place a thermite grenade in
the receiver on the bolt (with the cover resting on the grenade) and fire
the grenade. (This method may require the use of more than one
grenade. Remove the backplate group, place a thermite grenade in the
rear of the receiver and fire the grenade.
g. Disposal. Bury in suitable holes, or dump parts into streams, mud,
snow, sumps, latrines, or scatter the parts over a wide area.
CHAPTER 5
MARKSMANSHIP TRAINING
The procedures, exercises, and techniques for implementing a
proper marksmanship program are based on the concept that
all machine gunners must understand common firing
principles, be proficient marksmen, and be confident in
applying these skills in combat. This depends on their
understanding of the machine gun and their application of
marksmanship fundamentals. Proficiency is accomplished
through practice that is supervised by qualified trainers and
through objective performance amassments by the unit leaders.
The structure of this chapter is in four sections: planning,
fundamentals, basic marksmanship, and advanced gunnery.
All advanced exercises are conducted under conditions that
are as much like tactical conditions as possible.
(See| Appendix B|for training aids and devices.)
Section 1. PLANNING
The planning of MG training is no different from other marksmanship
training. Guidelines are provided to assist the trainers in understanding,
preparing, and ensuring that all training is conducted to standard. This
section addresses the objectives, the responsibilities of the commanders,
and the phases of training. It also introduces the training devices that assist
in training, and designates when remedial and sustainment training should
be conducted.
5-1. OBJECTIVES
The objectives of the MG training program are to guide the trainers,
leaders, and gunners through a sequence of training to standard that
produces a gunner who is able to maintain the gun and effectively engage
targets in combat.
5-2. COMMANDER’S RESPONSIBILITIES
The responsibilities of the commander are to ensure the instructors and
their assistants are thoroughly trained and rehearsed in the planning,
knowledge, and presentation of all MG training. He will ensure that safety
is emphasized and never overlooked during training. Serviceable weapons
5-1
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5-2
are a must for good training апа commanders must make sure they are
used properly. He also ensures sufficient time is scheduled.
5-3. PHASES OF TRAINING
The initial training strategy is divided into three phases of marksmanship
instruction — the fundamental phase, the basic marksmanship phase, and
the advanced gunner phase. Gunner safety is continuously stressed during
all phases of training.
a. In the fundamental phase, the gunner learns the necessary common
skills, such as dry-fire exercises, preparation of positions, manipulation of
the T&E, range determination, and sighting and aiming. The gunner must
master these skills before he is allowed to progress to the basic
marksmanship phase.
b. During the basic marksmanship phase, the gunner learns the basics
of loading, zeroing, laying, and engaging of single and multiple targets
from the tripod and vehicle mode.
c. The advanced gunnery phase trains the gunner in engaging moving
targets, night firing, NBC firing, mounted firing, and firing using fire
commands. The gunner will be placed under the stress and strain of
simulated combat conditions.
5-4. SUSTAINMENT TRAINING
Once individuals and units have trained to a required level of proficiency,
leaders must structure collective and individual training plans to conduct
critical task training at the frequency necessary for the sustainment
training strategy. Mission training plans and individual training evaluation
programs help achieve and sustain collective/individual proficiency.
Sustainment training prevents skill degradation. Army units must be
prepared to accomplish their wartime missions at any time — they cannot
rely on infrequent peaking to the appropriate level.
5-5. REMEDIAL TRAINING
Remedial training will be conducted in any of the phases of training where
the gunner does not meet the standard. The trainer must be instantly
aware of any gunner that seems to be having trouble. Once the problem
has been identified, the gunner should be retrained as soon as possible so
that he will maintain the same level of proficiency as the other gunners.
Section Il. FUNDAMENTALS
The fundamentals are necessary basic skills that a gunner must be trained
in before he can be expected to effectively engage targets. Personnel
conducting marksmanship training must fully understand the
fundamentals and be well rehearsed in applying them. The basics in MG
training are assuming a proper firing position, sighting, aiming,
determining range, and manipulating the T&E mechanism.
5-6. FIRING POSITIONS
Before a gunner can hit targets, he must learn to get behind the weapon in
a position that allows him to be comfortable, affords him protection, and
enhances mission accomplishment.
a. The tripod firing positions are prone, sitting, and standing. They are
assumed in the following manner.
(1) The prone position is used when firing from the tripod that is set
in a low position. It is assumed by lying on the ground directly behind the
gun. The gunner then spreads his legs a comfortable distance apart with
his toes turned outward. His left elbow rests on the ground, and his left
hand grasps the elevating handwheel of the T&E. His right hand lightly
grasps the right spade grip with his right thumb in a position to press the
trigger. The position of his body can then be adjusted to position his firing
eye in alignment with the sights of the weapon (Figure 5-1).
Figure 5-1. Prone position with tripod mount.
(2) The sitting position can be used when the tripod is set in a high or
low position. The gunner sits directly behind the gun between the legs of
the tripod. He may extend his legs under the tripod or cross them,
depending on his physique. The gunner then places both elbows on the
inside of his thighs to get the best support. He grasps the elevating
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handwheel of the T&E with the left hand, and lightly grasps the right
spade grip with his right hand. He must ensure that the right thumb is in
position to press the trigger (Figure 5-2).
Figure 5-2. Sitting position with tripod mount.
(3) The standing position is used when the gunner is firing from a
fighting position. This position is assumed by standing directly behind the
gun with the feet spread a comfortable distance apart. The gunner grasps
the elevating handwheel of the T&E with the left hand. He lightly grasps
the right spade grip with the right hand, ensuring that the right thumb is in
a position to press the trigger. Adjustment of the body is allowed in order
to align the firing eye with the sights on the weapon (Figure 5-3).
Figure 5-3. Standing position with tripod mount.
5-4
b. The vehicular firing position for the МС is standing. It is assumed
by constructing a solid platform to stand on, using sandbags or
ammunition boxes; or, in the case of the M113 APC, using the
commander's seat. The gunner must then ensure that his platform is high
enough to place the spade grips of the gun about chest high. He grasps the
spade grips with both hands and places both thumbs in a position to press
the trigger. The gunner holds the gun tightly to his chest for stabilization;
his elbows should be locked tightly to his sides. He sights over the weapon
and adjusts his position by flexing his knees and leaning forward to absorb
any recoil (Figure 5-4).
===,
a A шз ә me ae а
- сә ча а «а а ©
Figure 5-4. Standing position using cupola mount.
c. The antiaircraft firing position uses a standing position when firing
from the M63 mount. To assume the position, the gunner stands with his
feet spread comfortably apart with his shoulders squarely behind the gun
page 5-6). When the gunner is engaging aerial targets, he
grasps the upper extension handles with both hands. When engaging
low-level aircraft or ground targets, he grasps the lower extension handles
with both hands.
NOTE: The kneeling position may be used; it has the advantage of
presenting a lower profile of the gunner and also aligns the
gunner's eye closer to the axis of the barrel.
FM 23-65
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ЕМ 23-65
5-6
Figure 5-5. Antiaircraft firing position.
5-7. DRY-FIRE TRAINING
Dry-fire training is designed to teach the gunner the essentials of MG
gunnery, including safety. Dry-fire training also includes sighting, aiming,
sight setting, laying, manipulating the gun, manipulating the T&E
mechanism, and determining the range. Thorough, carefully supervised
training of these essentials is necessary to conserve time and ammunition
during live fire. Practical exercises should be used to determine gunners'
proficiency. Mastery of these skills is a must before the gunner is allowed
to move on to the next phase of training. Practice is a must to achieve
mastery.
a. Sighting and Aiming. Sighting is the ability of the gunner to use
correct sight alignment and correct sight picture to engage targets.
(1) The first step in proper sighting is finding a natural, comfortable
spot where the gunner is able to see the front sight blade through the rear
peep sight. It is important the gunner understands that the spot he chooses
to sight from must be constant throughout his firing.
(2) The second step in sighting is to move the weapon until the top
center of the front sight blade is exactly in the center of the rear sight peep
hole. The gunner can achieve this by drawing imaginary lines that bisect in
the center of the rear peephole and then placing the top of the front ight
blade center of them. This is correct sight alignment (Figure 5-6].
Figure 5-6. Correct sight alignment.
(3) The third step is to establish correct sight picture. To perform this
task, the gunner adjusts the weapon until the top center of the front sight
blade is bottom center of the intended target. Correct sight picture is a
combination of sight alignment and placement of point of aim
(Figure 5-7).
Figure 5-7. Correct sight picture.
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b. Range Setting and Laying. Range setting and laying the gun are
important elements in marksmanship training. It is this training that
prepares the gunner to accurately and rapidly place fire on his target in
combat. To properly set ranges, the gunner must be trained in rear sight
operation.
(1) Setting ranges on the rear sight is a simple but important task. The
gunner just has to rotate the elevating screw knob in a clockwise manner
to move the peep sight up or counterclockwise to move it down. The range
scale on the left is graduated in mils and the scale on the right in yards.
The gunner must align the hairline index of the peep sight with the scale
index line at the desired range as quickly and accurately as possible.
(2) Laying is placing the barrel of the weapon on a direct line with the
target, using the sights. This must also be done as quickly and accurately as
possible.
(3) The range setting and laying exercises are designed to require the
gunner to practice and the instructor to evaluate both correct sight
alignments and correct placements of aiming points. The exercise starts
with the gunner in the sitting firing position with rear sight down. The
coach will announce a range and general aiming point. The gunner will
then repeat the range and direction of target. The coach will then
announce, “Begin.” The gunner will then raise and set his sights, and align
the weapon on the aim point. When the gunner completes this task, he will
announce "Up." The coach will then get behind the weapon and check the
range setting and aim point and critique the gunner on his findings. This
exercise will be continued until speed and accuracy is obtained.
c. Traversing and Elevating Mechanism. Manipulation of the T&E
mechanism is another key factor in effectively engaging
targets. The gunner is taught how to instinctively manipulate the T&E
mechanism to shift from one target to another. The gunners are trained to
use the traversing handwheel, the traversing slide lock, and the elevating
handwheel.
(1) The traversing mechanism consists of a traversing handwheel,
locking nut, scale, and yoke. The T&E mechanism is attached to the
traversing bar of the M3 bipod.
(a) The traversing bar is graduated in 5-mil increments and fits
between the trail legs of the M3 tripod. The traversing slide and screw
assembly are clamped in place on the traversing bar by the traversing slide
lock lever. When the traversing slide is locked to the traversing bar, the
traversing handwheel should be centered. The traversing slide is properly
mounted when the lock lever is to the rear and the traversing handwheel is
positioned to the left.
LOCKING NUT
TRAVERSING
SCALE PLATE
ELEVATING
HANDWHEEL
TRAVERSING SIDE
^ LOCK LEVER
TRAVERSING BAR
umm ERU
O r]
(5 MILS BETWEEN (H= ELEVATING MECHANISM
SMALL LINES) SLEEVE
Figure 5-8. Traversing and elevating mechanism.
(b) To make changes in direction, loosen the traversing slide lock
lever and move the slide along the traversing bar. This permits traverse of
400 mils left or right of the zero index in the center of the traversing bar.
Readings on the traversing bar are taken from the left side of the
traversing slide. For changes of 50 mils or less in deflection, turn the
traversing handwheel. This allows a traverse of 50 mils left or right of
center. One click in the traversing handwheel signifies 1 mil change in
direction.
(2) The elevating mechanism consists of an upper and lower elevating
screw, which is connected to the gun by inserting the quick release pin
assembly through the holes in the upper elevating screw yoke and the rear
mounting lugs of the receiver. A scale, graduated in mils, is fitted to the
upper screw to indicate elevation. This scale is marked to show (-) minus
250 mils in depression and ( + ) plus 100 mils in elevation from the zero
setting.
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(3) The elevating handwheel is graduated in 1 mil increments from
0 to 50 mils and is fastened to the elevating screw by a screw lock. This
synchronizes the handwheel graduations with those on the upper elevating
screw. A spring-actuated index device produces a clicking sound when the
handwheel is turned. Each click equals 1 mil change in elevation. The
handwheel is turned clockwise to depress the barrel and counterclockwise
to elevate.
(4) Direction and elevation readings constitute the data necessary to
engage preselected target areas during limited visibility. These readings
are measured by and recorded from the traversing bar and the T&E
mechanism. To obtain accurate readings, the T&E must be first zeroed
with all measurements recorded in mils.
(a) To zero the traversing handwheel, the gunner must first hold the
T&E so that the traversing handwheel is on his left as he looks at it. He
then turns the handwheel toward himself until it stops, loosens the locking
nut slightly, and aligns the zero on the scale with the zero on the elevating
screw yoke. Once the zeros are aligned, he tightens the locking nut. He
must then turn the handwheel two complete turns away from the body and
stop. The scale should again be on the zero. If this procedure is done at
night, the gunner will turn 50 clicks away from him.
(b) To zero the elevating handwheel, the gunner must first turn the
handwheel up or down until the handwheel is level with the line directly
under the zero on the elevating screw plate scale, and the elevating
handwheel indicator is pointing to the zero on the top of the handwheel.
The elevating mechanism sleeve is then rotated up until it is stopped by
the handwheel. The gunner then rotates the sleeve down until it stops,
making sure he counted each complete rotation. He then divides the
number of rotations by two, rotates the sleeve back up that number, and
stops. The T&E mechanism is now ready to be attached to the tripod.
(c) To obtain and record direction readings, the gunner sets the sight
on the proper range to hit the target, loosens the traversing slide lock
lever, and slides the T&E mechanism along the traversing bar until the
weapon is sighted on the aiming point of the target. The T&E mechanism
is then locked down by tightening the traversing slide lock lever. All
readings are taken from the left side of the sleeve mechanism. If the left
side of the sleeve is not exactly on one of the 5-mil tick marks, the gunner
must slide the sleeve to the next smaller tick mark to align it exactly. The
traversing handwheel is then used to move the weapon back on point of
aim. The direction is now ready to be recorded. The reading is taken from
the number on the traversing bar and the direction from the direction of
the barrel of the weapon. If the sleeve mechanism is on the right side of
the zero on the traversing bar, then the reading is left; if it is on the left
side of the zero, then it is a right reading. The width of a target may also be
measured and recorded by first moving the traversing handwheel until the
sights are aligned with the right or left side of the target. The clicks
required to do this measure the width.
NOTE: Before repositioning the weapon for another target, the gunner
must realign the handwheel.
(d) To obtain an elevation reading, the gunner must first ensure that
the sights are aligned and at the desired aim point of the target. The
elevation reading is made up of two portions, a major reading and a minor
reading. The major reading is taken from the elevating screw plate scale.
The scale is graduated in 50-mil increments and ranges from a minus (-)
250 mils to a plus ( + ) 100 mils with a zero between them. There is an
index line below each number and a plus or minus sign above each
number, with the exception of the zero. The zero does not have a plus or
minus sign. To obtain the elevation reading, the gunner should lower his
head until his eyes are level with the elevating handwheel. The major
reading is the first number with a plus or minus sign, with its index line just
visible above the elevating handwheel. The minor reading is taken from
the top surface of the elevating handwheel. It is graduated in l-mil
increments for a total of 50 mils. The handwheel is also equipped with an
indicator that points to each number on the handwheel as it is turned.
Once the gunner has the major reading from the screw plate scale, he will
then get the minor reading by looking at the number at which the
indicator is pointing. Both portions of the elevation reading are recorded
by placing a slash (/) mark between the two portions.
(e) An elevation reading is valid only on one T&E mechanism. If the
same data is placed on another T&E mechanism using the same weapon,
the data may be inaccurate. The number of threads exposed on the T&E
must remain the same both when obtaining and recording data. If the
number of exposed threads is changed in any manner, the firing will be off
target. For example, when a gun is freed to engage targets in the secondary
sector, the data will be correct if the gunner ensures that the same amount
of threads is exposed when he returns to his primary sector of fire.
(f) To ensure that the data is correct, the gunner should fire and adjust
his weapon.
(5) The T&E manipulation exercise gives the gunner practice and the
instructor a tool to evaluate the gunner's progress page 5-12).
The exercise is conducted in two stages. Both stages require the coach to
give directions and the gunner to respond. In the first stage, the coach
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5-12
positions himself about 10 paces to the front of the gun. He then directs
the gunner to manipulate the weapon in certain directions. He indicates
the direction by the use of hand signals. The gunner responds by
manipulating the T&E mechanism with his left hand. The gunner must
keep his eyes on the coach; at no time during this exercise is he permitted
to look at the T&E mechanism. The coach must be very attentive during
the first stage because the gunner will be manipulating using the elevating
handwheel and the traversing handwheel. The second stage is done in the
same way except the gunner must make bold changes in elevation and
deflection. The exercise continues until the instructor is satisfied that the
gunner can manipulate the weapon by T&E without looking at the device.
This exercise can also be conducted using the basic MG target. The
gunner will be shifted from one selected target to another. The coach must
observe all movements of the gunner during this training.
GUNNER
Figure 5-9. Manipulation exercise.
5-8. RANGE DETERMINATION
Range determination is the process of estimating the distance to a target
from a gunner’s position. The ability of the gunner to get the range to,
sight on, and destroy a target is the realism of combat. Under combat
conditions, ranges are seldom known in advance; therefore the
effectiveness of fire depends largely upon the accuracy and speed of the
gunner in determining range. Some methods of determining range are
estimating by eye (Table 5-1, page 5-15), firing the gun, measuring range
from a map or aerial photograph, stepping off the distance, or securing
information from other units. Ranges are determined to the nearest
100 meters for machine gun firing. In combat, the most commonly used
methods are estimating by eye and firing the gun. There is also a method
used for measuring lateral distance.
ЕМ 23-65
a. The two techniques of eye estimation are the 100-meter unit of
measure method and the appearance of objects method.
(1) When using the 100-meter unit of measure method, the gunner
must be able to visualize what 100 meters looks like on the ground. With
this distance in mind, the gunner can mentally determine the number of
100-meter units between his position and the target. The accuracy of this
method is limited to 500 meters or less, and it requires constant practice
(Figure 5-10).
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2007
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5 i E
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ov. АЩ,
Figure 5-10. 100-meter unit of measure method,
less than 500 meters.
(2) For targets that appear to be more than 500 meters, the gunner
must modify this technique. The gunner selects what he thinks is the
halfway point between the target and his position. He then mentally
counts the number of 100-meter units to the halfway point and doubles it.
This method of range determination is not accurate beyond 1,000 meters
page 5-14).
(3) Some terrain affects the appearance of 100-meter units of
measure. When the terrain slopes upward toward the target, 100 meters
appears longer than on level terrain. It appears shorter on downward
5-13
ЕМ 23-65
5-14
sloping terrain. The gunner must consider these two factors when using
the 100-meter unit of measure method.
HALFWAY
POINT
Figure 5-11. TATE Unit of measure method,
more than 500 meters.
(4) The appearance of objects method may be used if the gunner is
unable to use the 100-meter unit of measure method because of terrain.
To use this method, the gunner learns through practice how familiar
objects look at various known ranges. This can be achieved by studying the
appearance of a man standing 100 meters away. The gunner must then fix
the appearance of the man firmly in his mind to include the size and
details of his uniform and equipment. Next, he studies the same man at
the same distance in the kneeling and prone positions. This procedure is
used at 200, 300, 400, and 500 meters. By comparing the appearance of the
man at these known ranges, he can establish a series of mental images that
will help him determine range on unfamiliar terrain out to 500 meters.
This training could also be conducted to familiarize the gunner with other
objects, such as weapons and vehicles, at various ranges.
ЕМ 23-65
APPEARS NEARER (Range is APPEARS MORE DISTANT (Range
FACTOR underestimated when) — is overestimated when) —
Target visibility. Most of the target is visible and Only a small part of the target is
offers a clear outline. seen or target is small in relation
to its surroundings.
Terrain, or position of Looking across a depression, most Looking across a depression, all
the observer. of which is hidden from view. of which is visible. Looking from
Looking down from high ground. low toward high ground. When
Looking down a straight, open vision is narrowly confined as in
road or along a railroad track. streets, draws, or forest trails.
Looking over uniform surfaces
such as water, snow, desert, or
grain fields.
Light and atmosphere In bright light or the sun is shining In poor light such as dawn and
from behind the observer. dusk, in rain, snow, fog, or when
The target is in sharp contrast with the sun is in the observer's eyes.
the background, or is silhouetted The target blends into the
by reason of size,shape, or color,or background or terrain.
is seen in the clear atmosphere of
high altitudes.
b. Firing the gun is another method of determining range. In this
method, the gunner opens fire on the target at the estimated range and
moves the center of the beaten zone into the center base of the target by
means of the T&E handwheels. He resets the sight so the new line of aim
is at the center base of the target and notes the range setting on the rear
sight. This range setting may apply only to this gun. When the ground in
the vicinity of the target does not permit observation of the strike of the
rounds, or when surprise fire on the target is desired, fire is adjusted on a
point that offers observation and is known to be the same range as the
target. The gunner then lays his gun on the target when ordered. When
moving into position occupied by other units, range cards prepared by
those units can furnish valuable range information on targets, suspected
targets, and various terrain features. When the tactical situation and time
permit, range may be determined by pacing off the distance.
c. Lateral distance measure is a method that the gunner may use to
determine the distance from one target to another from left to right or
right to left. When the gun is mounted on the M3 tripod, width can be
measured by aiming on a point and manipulating the traversing
handwheel, counting the clicks from one point to another point of aim.
Each click equals one meter at 1,000 meters or one-half meter at 500
meters. This method is accurate but time-consuming. The finger
Table 5-1. Factors affecting range estimation by eye.
5-15
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5-16
measurement method is not a method of range determination; it is a
method of measuring the lateral distance (in fingers or mils) between two
points. To measure the distance in fingers between a reference point and a
target, extend the arm with palm outward, the fingers cupped, and elbow
locked. Close one eye, raise the index finger, and sight along its edge,
placing the edge of the finger along the flank of the target or reference
point (Figure 5-12). The remaining space is then filled in by raising fingers
until the space is covered. The measurement is then stated as being one or
more fingers or so many mils, depending on the number of fingers used
(Figure 5-13).
HILL 905
Жо Ж
A yi Уд M
30 MILS 70 MILS 100 MILS 125 MILS
Figure 5-13. Mil/finger relationships.
5-9. OBSERVATION AND ADJUSTMENT OF FIRE
The purpose of observation and adjustment of fire practice is to teach the
adjustment of fire by observing the strike of the bullets and the flight of
the tracers, or by frequent re-laying on the target using sights.
a. Observation is used when firing on the 10-meter range because the
impact of the round is visible on the target. When firing at greater
distances, the strike of the round on the ground may cause dust to rise that
is visible to the gunner; however, during wet weather, the strike cannot
always be seen. In this case, use tracer ammunition that allows the gunner
or crew to note the strike of the burst in relation to the target.
b. Adjustments on the target can be made using the mil relation; that
is, one click of traversing or elevating handwheel moves the strike of the
round one-half inch on the target at 10 meters. When firing on field
targets, adjustment is made by moving the burst into the target. One click
of traverse will move the strike of the round one-half meter at 500 meters,
or one meter at 1,000 meters (Figure 5-14). However, the distance one
click of elevation will move the strike of the round depends on the range
to the target and the slope of the ground. The gunner determines the
number of mils necessary to move the center of the strike into the target,
and he manipulates the gun the required number of mils. This does not
require the use of sights. For example, should the gunner fire on a target
at 500 meters and observe the strike 10 meters to the right of the target
and short about 50 meters, he would traverse the gun to the left 20 clicks
(mils) and add one or more clicks (mils), depending on the slope.
1 METER 1,000 METERS
ш
P BEEN
VOMETER 500 METERS
M2 REAR SIGHT
Figure 5-14. Mil relation.
FM 23-65
5-17
ЕМ 23-65
5-18
c. The gunner may use the adjusted aiming point method to adjust the
fire. In this method, the gunner must use his sights. He selects an aiming
point that will place the next burst on target. For example, when the
gunner fires on a target at 500 meters and estimates that the rounds
impacted 20 meters short and 10 meters to the right, he would rapidly
select an aiming point about 20 meters beyond the target and 10 meters to
the left of it and lay on that aiming point and fire (Figure 5-15).
Figure 5-15. Adjusted aiming point method of fire adjustment.
5-10. FIRE COMMANDS
Fire commands are technical instructions issued by a leader to enable the
unit or crew to accomplish a desired fire mission. Fire commands have
been standardized for infantry direct fire weapons, and they follow the
same sequence. There are two types- initial fire commands, issued to
engage a target; and subsequent fire commands, which are issued to adjust
fire, change the rate of fire, interrupt fire, shift fire to a new target, or to
terminate the alert. A correct fire command is one that is as brief as clarity
permits and yet includes all the elements necessary for the
accomplishment of the fire mission. It is given in the proper sequence,
transmitted clearly at a rate that permits receipt and application of
instructions without confusion.
a. Elements of the Initial Fire Command. There are six essential
elements of the initial fire command for the machine gun, which are given
or implied by using one or more of the methods of control. During
training, the gun crew repeats each element as it is given. This is done to
avoid confusion and to train the crew to think and act in the proper
sequence. The six elements are the alert, direction, description, range,
method of fire, and the command to open fire.
(1) Alert. This element brings the crew to a state of readiness to
receive further instructions. Once alerted, the gunner ensures the gun is
loaded. The assistant gunner continuously checks with the leader for
orders or instructions and passes them on to the gunner. The oral alert is
announced as FIRE MISSION. At this command, the gunners are alerted
that a target has been detected and fire may be delivered upon it. When
the leader announces the alert, such as FIRE MISSION, both gun crews
react to the alert. If only a certain gun is to engage, the leader announces
NUMBER 1 (or 2). The other crew follows the fire mission, loads, and
lays on the target to take up the fire, if required.
(2) Direction. This element indicates the general direction to the
target and may be given in one or a combination of the following ways:
(a) The leader gives the direction orally to the target in relation to the
position of the gun(s). For example, FRONT, RIGHT FRONT, LEFT
FRONT.
(b) The leader can designate a small or obscure target by pointing
with his arm and hand or aiming the machine gun. When pointing with his
arm and hand, a man standing behind him should be able to look over his
shoulder and sight along his arm and index finger to locate the target.
When a gun has been aimed at a target, a soldier looking through the
sights should be able to see the target.
(c) Tracer ammunition is a quick and sure method of designating a
target that is not clearly visible. When using this method, the leader should
first give the general direction to direct the gun crew's attention to the
desired area. To minimize the loss of surprise when using tracer
ammunition, the leader does not fire until he has given all the elements of
the fire command except the command to fire. The leader may use his
individual weapon or fire one or more bursts from the machine gun. The
firing of the tracer(s) then becomes the last element of the fire command
and is the signal to open fire. For example:
FIRE MISSION.
FRONT.
BUNKER.
WATCH MY TRACER(S).
SLOW (or SINGLE SHOT).
The leader fires his individual weapon or a machine gun at the enemy
bunker, then his gun crew(s) opens fire.
(d) Another method of designating obscure targets is by using easily
recognizable reference points. Prominent terrain features and man-made
FM 23-65
ЕМ 23-65 000
objects make good reference points. All leaders and members of the
crew(s) must be familiar with the terrain features and the terminology
used to describe them. The general direction to the reference point should
be given. For example:
FIRE MISSION, NUMBER 2.
FRONT.
REFERENCE: LONE PINE TREE.
TARGET: TRUCK.
Sometimes a target must be designated by using successive reference
points. For example:
FIRE MISSION, NUMBER 1.
RIGHT FRONT.
REFERENCE: RED-ROOFED HOUSE, LEFT TO HAYSTACK
LEFT TO BARN.
TARGET: MACHINE GUN.
Finger measurements can be used to direct the gun crew’s attention to the
right or left of reference points. For example:
FIRE MISSION.
LEFT FRONT.
REFERENCE: CROSSROAD. RIGHT FOUR FINGERS.
TARGET: LINE OF TROOPS.
When the guns are mounted on tripods, lateral distance from reference
points can be accurately announced. When gunners are firing the
tripod-mounted gun, lateral distance is assumed to be in mils unless
otherwise indicated, so the word “mils” is not necessary. For example:
FIRE MISSION.
FRONT.
REFERENCE: KNOCKED-OUT TANK. LEFT FOUR ZERO.
TARGET: COLUMN OF TROOPS.
(3) Description. The target description is used to create a picture of
the target in the minds of the gun crew. The gun crew must know the type
of target they are to engage to properly apply their fire. The leader should
describe it briefly but accurately. For example:
Dismounted enemy personnel... TROOPS
Automatic weapons... MACHINE GUN
Armored vehicles iuc DR DR nun wie nacre’ TANK
Artillery or antitank Weapons ANTITANK
Airplanes or helicopters enne AIRCRAFT
If the target is obvious, no description is necessary. Finger measurements
or mil measurements can be used to designate the width of a linear target
when the flanks cannot be pinpointed.
»
(4) Range. The range to the target is given so the gun crew knows how
far to look for the target and immediately knows what range setting to
place on the rear sight. Range is determined and announced in meters.
Since the meter is the standard unit of range measurement, the word
"meters" is not announced. With machine guns, the range is determined
and announced in even hundreds and thousands. For example: THREE
HUNDRED, ONE THOUSAND, ONE ONE HUNDRED. This element
may be omitted when the gunners can obviously determine the range;
however, it is desirable in some situations to announce the range.
(5) Method of fire. This element includes manipulation and rate of
fire.
(a) Manipulation is used to prescribe the class of fire with respect to
the gun. It is announced FIXED, TRAVERSE, SEARCH, TRAVERSE
AND SEARCH, SWINGING TRAVERSE, or FREE GUN.
(b) To control the rate of fire, the gunner may use single shot, slow,
rapid, or cyclic.
Single shot. Place the gun in the single-shot mode and engage the
target with aimed shots. The MG is accurate out to 1,500 meters.
Slow fire. Slow fire consists of less than 40 rounds per minute, in
bursts of five to seven rounds, fired at 10- to 15-second intervals.
Rapid fire. Rapid fire consists of more than 40 rounds per minute,
fired in bursts of five to seven rounds, at 5- to 10-second intervals.
* Cyclic fire. Cyclic fire is when the weapon fires 450 to 550 rounds
per minute.
(6) Command to open fire. If surprise fire is not desired, the command
FIRE is given without pause. It is often important that machine gun fire be
withheld for maximum effect of surprise fire. To ensure this, the leader
may preface the command to commence firing with the words AT MY
COMMAND or AT MY SIGNAL. When the gunner(s) is ready to engage
the target, he reports UP to the assistant gunner(s) who signals READY
to the leader. For example:
FIRE MISSION.
FRONT.
TROOPS.
AT MY COMMAND. (Pause until crew members are ready
and fire 1s desired.)
FIRE (or appropriate arm-and-hand signal).
FM 23-65
5-21
ЕМ 23-65
5-22
When the leader makes a mistake in the initial fire command, he corrects
it by announcing CORRECTION, and then gives the corrected
element(s). For example:
FIRE MISSION.
FRONT.
TROOPS.
FIVE HUNDRED.
CORRECTION.
SIX HUNDRED.
TRAVERSE.
AT MY COMMAND.
When the leader makes an error in the subsequent fire command, he may
correct it by announcing CORRECTION, and then repeating the entire
subsequent fire command. For example:
LEFT FIVE, DROP ONE.
CORRECTION
LEFT FIVE, DROP ONE ZERO.
b. Subsequent Fire Commands. If the gunner fails to adjust his fire on
the target, the leader must promptly correct him by announcing or
signaling the desired changes. When changes are given, the gunner makes
the required corrections and continues to engage the target without
further command. When firing under the control of a leader, the assistant
gunner checks with the leader for instructions, which he passes on to the
gunner. Changes in the rate of fire are given orally and by arm-and-hand
signals. To interrupt firing, the leader announces CEASE FIRE or gives a
signal to cease fire. The gun crew(s) remains on the alert and firing can be
resumed on the same target by announcing FIRE. To terminate the alert,
the leader announces CEASE FIRE, END OF MISSION.
5-11. CREW EXERCISES
The purpose of crew exercise is to develop precision, speed, skill, and
teamwork in examining equipment, placing the gun into action, and taking
it out of action. In crew exercise, precision must be stressed. Once that is
attained, speed, skill, and teamwork will follow. Duties are rotated during
crew exercise to allow each member of the gun crew to become familiar
with all the duties. During crew exercise, all oral or visual signals are
repeated. When the fire command is completed, the gunner will give the
assistant gunner an UP. The assistant gunner will extend his hand and arm
into the air in the direction of the leader (to indicate READY) and
announce, UP. With the M3 mount, the crew must consist of at least four
men, including the leader. There is no designated crew in the TOE for a
ЕМ 23-65
dismounted caliber .50 MG. The following paragraphs are only
suggestions for the breakdown of equipment and member designation that
may be established by the commander.
a. Crew Equipment. In addition to individual arms and equipment,
crew members carry the following equipment for the tripod-mounted
machine gun:
CREW MEMBER SUGGESTED MINIMUM EQUIPMENT
Squad or crew leader. Binoculars, compass, one box of
ammunition.
No. 1 Assistant gunner. Tripod.
No. 2 Gunner. Receiver, T&E mechanism attached,
and headspace and timing gauge.
No. 3 Ammunition bearer. Barrel, barrel cover, and box of
ammunition.
b. Form for Crew Exercise. The crew leader commands, FORM FOR
CREW DRILL.
(1) Positions with equipment. The crew forms in column, facing the
crew leader with five paces between men page 5-24). They
are in the following order: assistant gunner, gunner, and ammunition
bearer. When the crew members reach their correct positions, they
assume the prone position with equipment arranged as follows:
(a) No. 1: Tripod to his left, trail legs to the rear, front leg uppermost.
(b) No. 2: Receiver across his front, backplate to the right, retracting
slide handle uppermost.
(c) No. 3: Barrel to his right, muzzle to the rear, ammunition box to
his left front with latch to the right (latch to the front for the new box).
(d) Other members, if present Ammunition boxes in front, one foot
apart, latches to the right (front).
(e) Crew leader: Ammunition box to his right as he faces the crew,
latch to the right (front).
(2) Rotation of duties. Duties are rotated to ensure that each member
learns and is capable of performing the duties of the other members.
(a) The command to rotate all personnel is, FALL OUT LEADER.
At this command, each member of the crew rises, moves forward, and
assumes a new duty. The crew leader becomes the ammunition bearer.
The assistant gunner moves forward and becomes the crew leader. The
gunner moves forward and becomes the assistant gunner. The ammunition
bearer moves forward and becomes the gunner.
5-23
ЕМ 23-65
(b) If the leader is not changed, the command, FALL OUT
ASSISTANT GUNNER, is given. At this command, the crew members
rise, the gunner becomes the assistant gunner, the ammunition bearer
becomes the gunner, and the assistant gunner becomes the ammunition
bearer. When the crew members have assumed their new position, they
call out their new duties in order, ASSISTANT GUNNER, GUNNER,
AMMUNITION BEARER.
NOTE: An additional crew exercise, which the crew maybe required to
practice, is the setting of headspace and timing. These procedures
are outlined in| paragraph 3-6.|
Figure 5-16. Crew formed in column.
c. Inspection of Equipment Before Firing. When the crew is formed
with equipment, the command is, INSPECT EQUIPMENT BEFORE
FIRING. At this command, the crew proceeds as follows:
(1) The assistant gunner inspects the tripod M3 mount to ensure that:
(a) The indexing levers and clamps on the front and trail legs function
properly, and the legs are in the short (low) position.
(b) The front leg and trail legs are closely folded, and the front leg
clamp is hand tight.
(c) The sleeve lock latch and pintle lock release cam are in working
order, and the pintle lock release cam is down.
(d) The pintle bushing is free from dirt and burrs.
(2) The gunner inspects the receiver group to ensure that:
5-24
(a) The barrel support and breech bearing are free of dirt.
(b) The gun pintle is free of dirt.
(c) The feed mechanism and bolt switch are properly assembled to
feed from left (soldier raises cover for proper inspection).
(d) The striker projects through the aperture in the face of bolt
(soldier closes the cover).
(e) The rear sight is set at 1,000 yards (900 meters) windage zero.
(f) The T&E mechanism is securely attached to the receiver.
(g) The traversing handwheel is centered.
(h) The elevating screws are equally exposed (about 2 inches) above
and below elevating handwheel.
(1) The backplate is latched and locked in place.
(j The bolt latch release is locked in the down position by the bolt
latch release lock.
(3) The ammunition bearer inspects the barrel and ammunition box to
ensure that:
(a) The barrel is clear.
(b) The barrel carrier assembly is securely attached to the barrel.
(c) The barrel threads are free of dirt.
(d) The metallic links are clean (soldier opens ammunition box).
(e) The belt is properly loaded and placed in box with the
double-looped end up.
(ff Dummy ammunition is used during crew exercise, and no live
ammunition is present.
(g) The box is closed and latched.
(4) When the ammunition bearer completes his inspection, he moves
to the gunner's position with the barrel in his right hand and ammunition
box in his left hand. With the aid of the gunner, he screws the barrel into
the barrel extension (Figure 5-17,]page 5-26). The headspace and timing
adjustment is made. The ammunition bearer remains on the left and on
line with the gunner.
(5) The crew leader examines his ammunition as described in
paragraph (3).
(6) At the completion of the inspection, a report is rendered as
follows:
(a) The ammunition bearer reports: AMMUNITION CORRECT (or
any deficiencies).
(b) The gunner reports: GUN AND AMMUNITION CORRECT (or
any deficiencies).
(c) The assistant gunner reports: ALL CORRECT (or any
deficiencies).
FM 23-65
5-25
ЕМ 23-65
5-26
Figure 5-17. Screwing the barrel into the barrel extension.
d. Placement of the Gun Into Action. To place the gun into action, the
crew leader commands and signals, GUN TO BE MOUNTED HERE
(pointing to the position where the gun is to be mounted), FRONT
(pointing in the direction of fire), ACTION (vigorously pumping his fist in
the direction of the designated gun position).
(1) At the command or signal ACTION, the assistant gunner grasps
the left trail leg near the center with his left hand. Springing to his feet and
grasping the tripod head with his right hand, he lifts the tripod across the
front of his body with the front leg up, and carries the tripod to the desired
location. Upon arrival at the position, he places the trail leg pointing
upward. Steadying the tripod with his left hand on the front leg, he loosens
the front leg clamp with his right hand KFigure 5-18), positions the front
leg with his left hand, and tightens the front leg clamp with his right hand.
With his right hand on the tripod head, he slides his left hand down on the
left trail leg and with a snapping motion, pulls the left leg (to the left),
engaging the sleeve latch (Figure 5-19). He then aligns the tripod for
direction, drops the mount to the ground, stamps the right and left trail
shoes with his right or left foot, and assumes the prone position behind the
mount.
Figure 5-19. Emplacing the mount.
5-27
ЕМ 23-65
5-28
(2) The gunner and ammunition bearer move together. When the
tripod is nearly mounted, the gunner and ammunition bearer spring to
their feet. The gunner places both hands on the spade grips, the
ammunition bearer grasp the ammunition box in his left hand and the gun
carrying handle with this right hand. Both men lift the gun from the
ground and move rapidly to the gun position. Then the ammunition bearer
places the ammunition box on line and in front of the leader's ammunition
box. The gunner, assisted by the ammunition bearer, inserts the pintle into
the pintle bushing. The ammunition bearer stamps the front shoe into the
ground with his left foot (Figure 5-20), releases the carrying handle,
lowers his right hand, and lifts the gun pintle lock release cam. When the
gun pintle is fully seated, he presses down the pintle lock release cam with
his right hand, turns to his left, and returns to his original position.
Figure 5-20. Mounting the gun.
(3) The assistant gunner holds the left spade grip with his left hand.
With his right hand, he lowers the T&E mechanism to the traversing bar,
ensuring that the traversing handwheel is to the left and the lock lever is to
the rear. He then assumes a semiprone position to the left of the gun with
his feet to the rear and his head on line with the feedway. He unlatches
and raises the cover of the ammunition box, removes the ammunition belt,
ЕМ 23-65
inserts the double-looped end into the feedway, and taps the feedway with
his right hand to ensure it is closed.
(4) With his right hand palm-up, the gunner grasps the retracting slide
handle, vigorously jerks it to the rear, and releases it. The gun is
half-loaded (Figure 5-21). He then assumes a prone position directly
behind the gun with his legs spread and heels down. His right hand lightly
grasps the right spade grip with the thumb in position to depress the
trigger. His left hand is on the elevating handwheel (palm down) with his
thumb near the traversing slide lock lever. He rests on his left elbow with
his head as close as possible to the rear sight page 5-30). He
then gives the assistant gunner an UP. The assistant gunner announces UP
and extends his hand and arm into the air in the direction of the leader.
Figure 5-21. Gun mounted, gunner half-loading the gun.
5-29
ЕМ 23-65 $$
Figure 5-22. Crew ready for action.
e. Removal of the Gun From Action. To take the gun out of action, the
command is OUT OF ACTION.
(1) The gunner raises the cover with his left hand, the assistant gunner
lifts the ammunition out of the feedway, replaces the ammunition in the
box, and closes and latches the box. The gunner closes the cover, pulls the
retracting slide handle to the rear with right hand (palm up) and releases
it, presses the trigger with his right thumb, and loosens the traversing slide
lock with his left hand. He rises to his feet, grasping both spade grips. At
this time, the ammunition bearer will arrive at the gun position. With his
left hand, the ammunition bearer grasps the ammunition box and places
his right foot on the front leg shoe. With his right hand, he reaches down
and lifts up the pintle lock release cam and grasps the carrying handle
[Figure 5-23].
(2) The gunner and ammunition bearer lift the gun from the tripod,
turn right, and carry the gun back to their original position. They set the
gun down with the muzzle to the left and the retracting slide handle up.
The gunner pulls the retracting slide handle to the rear and aligns the lug
on the barrel locking spring with the 3/8-inch hole in the right side of the
receiver. The ammunition bearer unscrews the barrel from the receiver,
picks up the ammunition box and barrel, moves five paces to the rear,
places the barrel to his right with the muzzle to the rear and the
ammunition box to his left, and assumes the prone position.
S
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Figure 5-23. Crew taking the gun out of action.
(3) The gunner rotates the bolt latch release lock to the right and
releases the bolt latch. He checks his sights to ensure they are properly set.
(4) The assistant gunner assumes a kneeling position behind the
tripod and releases the sleeve lock latch with his right hand. He rises to his
feet, grasps the front leg with his left hand, and rotates the tripod to a
vertical position on the trail legs. With his right hand, he loosens the front
leg clamp, folds down the front leg, then tightens the clamp. With his right
hand on the tripod head, he rotates the tripod on the right trail leg and
releases the sleeve latch. Then he folds the left trail leg against the right
with his left hand page 5-32). Holding the tripod head with
his right hand, trail legs with his left, he lifts the tripod across the front of
his body with the front leg up. He turns to the right and returns to his
original position. At this time, the crew leader picks up his ammunition
box and faces the crew. The assistant gunner places the tripod on the
ground, assumes a prone position to the right of the tripod, and
announces UP.
FM 23-65
ЕМ 23-65
5-32
Figure 5-24. Folding the trail legs.
f. Duties of The Crew. To hand-carry the gun and equipment, the
command is SECURE EQUIPMENT, FOLLOW ME. At this
command,-
(1) The crew leader carries his ammunition box in his right hand.
(2) The assistant gunner carries the tripod over either shoulder.
(3) The gunner carries the receiver on either shoulder with the spade
grips to the front.
(4) The ammunition bearer carries his ammunition box in his left
hand and the barrel in his right hand with the muzzle to the rear (or on his
left shoulder with the muzzle to the front).
g. Relocation of Tripod-Mounted Gun. When the gun is mounted on
the tripod, it can be moved for short distances by dragging or by a two- or
three-man carry. (In the latter, the men should move in step to make
carrying easier.)
(1) Dragging. The gun is dragged when there is limited cover, or when
the situation requires the gun to be moved in this manner. The gunner and
assistant gunner drag the mounted gun to the desired position
[Figure 5-25].
(2) Two-man carry With the gunner on the right and assistant gunner
on the left, each grasps the front leg with his forward hand and a trail leg
with the other hand, just above the traversing bar [Figure 5-26].
Figure 5-26. Two-man carry.
FM 23-65
5-33
ЕМ 23-65
5-34
(3) Three-man carry. When the barrel is hot, the gunner gets behind
the tripod with a trail leg in each hand. With the assistant gunner on the
left and the ammunition bearer on the right, each grasps the carrying
handle. In addition, the assistant gunner carries the ammunition in his left
hand (Figure 5-27). When the barrel is cool, the ammunition bearer and
the assistant gunner each grasp the front leg (Figure 5-28).
=
Es
ZA
DED
Figure 5-27. Three-man carry (hot barrel).
Figure 5-28. Three-man carry (cola barrel).
NOTE: Carrying the gun by the barrel may cause damage to the barrel
support and the barrel extension.
h. Movement of the Gun to Other Mounts. With the mount prepared
to receive the gun, the cradle of the mount is placed in a horizontal
position. To move the gun to the mount, the gunner carries the right spade
grip in his left hand and a box of ammunition in his right. The assistant
gunner grasps the carrying handle with his left hand and a box of
ammunition in his right hand. When they get to the mount, the gunner and
assistant gunner place their ammunition boxes near the mount. The
gunner removes the rear mounting (gun-locking) pin with his right hand.
The assistant gunner removes the front mounting (gun-locking) pin with
his right hand. They place the gun on the mount. The gunner aligns the
holes in the rear mounting lugs of the receiver with the rear mounting
bracket and inserts the rear mounting pin. The assistant gunner aligns the
front mounting hole in the front of the receiver with the front mounting
bracket and inserts the front mounting pin. (For use of the sideplate
trigger with the M63 mount, see TM 9-1005-213-10.)
FM 23-65
5-35
ЕМ 23-65
5-36
5-12. MACHINE GUN FUNDAMENTAL SKILLS TEST
The machine gun fundamental skills test should be held periodically to
ensure that proficiency with the MG is maintained by all crewmen. It
consists of 10 fundamental skills; all tasks are hands-on (Figure 5-29). The
test should be given prior to range firing on a go/no-go basis.
TASK GO/NO-GO
. Clear the MG.
. Disassemble the MG.
. Assemble the MG.
à Dea function check.
А піаіп {һе МС.
. Set the headspace on the MG.
. Set the timing on the MG.
. Load the MG.
. Perform immediate action on the MG.
. Unload the MG.
KS SAAS SS
1
2
3
4
5
6
7
8
9
0
—
Figure 5-29. The MG fundamental skills test.
Section Ill. BASIC MARKSMANSHIP
This phase of training is designed to allow the gunner to apply the
fundamentals of marksmanship that he learned earlier. During this
training, the gunner is introduced to the basic machine gun target (see
[Appendix C], procedures for both the 10-meter and field fire ranges, and
how to acquire targets. He also fires practice and qualification.
5-13. CONCEPT OF ZEROING/TARGETING
The concept of zero is very simple; it is no more than the best way to
adjust the sights of the weapon so the point of aim of the sights and the
point of impact of the rounds are the same at any given range. A properly
zeroed M2 gives the gunner the highest probability of hit for most combat
targets with the least adjustment to the point of aim. There are three
methods of zeroing/targeting used with the .50 caliber MG.
a. Ten-meter zero is the basic and the most common method of
zeroing the M2 MG. Once zeroed on a 10-meter range using the standard
machine gun target, the weapon is ready for field fire. As other weapons,
the sight on the M2 must also be set at an initial start point (Figure 5-30).
The initial sight setting for field zero is basically the same; except the
range setting during field zero will depend on the range to the target, and
it is always 1,000 yards for 10 meters.
ЕМ 23-65
(1) Set elevation. Raise the rear sight by lifting straight up until it snaps
into the upright position. Adjust the range scale to 1,000 yards by rotating
the elevation screw knob in the necessary direction. (Clockwise moves the
scale up; counterclockwise moves the scale down.)
(2) Set windage. Rotate the windage knob until the zero index mark on
the base rear sight is aligned with the index mark on the top of the
receiver. (Clockwise moves the windage scale to the left;
counterclockwise moves it to the right.)
RANGE IN YARDS ELEVATING SCREW
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М vA a
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BATTLE APERTURE
js pose
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WINDAGE IN MILS
WINDAGE KNOB
Figure 5-30. Rear sight setting.
(3) Obtain proper sight picture. Obtain the proper sight picture by
looking through the zero aperture and centering the front sight blade in it.
Once the sight alignment is obtained, place this combination on the center
base of the selected target (Figure 5-31).
(.)
ae ee
Figure 5-31. Proper sight picture.
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b. Field zeroing/targeting is an expedient method of obtaining a zero
when a 10-meter zero cannot be conducted. When preparing to field zero,
make sure the M2 is mounted securely on the M3 tripod, make sure the
T&E is working properly, and finally, know the distance to your zero
target. The only difference in initial sight setting for field zero is range
setting on the scale. The gunner must also remember that the range scale
on the M2 is indicated in yards. Therefore, in order to get as close to the
target as possible, you may have to convert the meters to the target into
yards so you can set the range on the rear sight. Conversion of meters to
yards is accomplished by multiplying the number of meters by 1.094. For
example, 600 meters x 1.094 — 656.4 yards; the gunner would set his range
scale at 650.
c. The AN/TVS 5 is an effective night fire aid. By using this device, the
gunner can observe the area and detect and engage any suitable target.
But, as usual, the device is only as good as its zero; the zeroing procedure
requires practice to become proficient.
(1) Mount the mounting bracket. To mount the bracket, the gunner
must ensure that the rear sight is in the down position. He then releases
the catch on the left side of the top cover assembly and raises the cover to
the upright position. He pushes the mounting bracket over the breech of
the machine gun and slides the bracket rearward until it stops
(Figure 5-32).
SLIDE MOUNTING
BRACKET TO REAR
Figure 5-32. Mounting the bracket.
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He pushes the three locking cams to secure the bracket (Figure 5-33) and
closes the top cover assembly.
Figure 5-33. Securing the bracket.
(2) Install the sight on the mount. To install the sight, the gunner must
align the scribe lines on the sight with the scribe lines on the bracket. He
places the sight in the groove at the top of the bracket and tightens the
lever screw to secure the sight to the bracket (Figure 5-34).
Figure 5-34. Securing the sight.
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(3) Zero the AN/TVS-5. A gunner must zero the MG with its NVD on
it before he can effectively engage targets with the AN/TVS-5. The
zeroing of this device to the MG must be done at 50 meters. An M16AI,
A2, or Canadian bull zero target may be used. The point of impact for
either target must be 9.8 centimeters below the target aiming point. To
accomplish this task, place the reticle aiming point on the target aiming
point (Figure 5-35).
PROPER SIGHT
PICTURE FOR
м.2
| DESIRED IMPACT
POINT OF ROUNDS
Ennn
A TTT и
ALGE
Figure 5-35. Desired impact point for the AN/TVS-5.
(a) Fire enough single-shot rounds to obtain a good shot group.
Locate the center of the shot group. Adjust the AN/TVS-5 azimuth and
elevation knobs until the shot group impacts 9.8 centimeters below the
target aiming point. Move the weapon so that the reticle aiming point is
again on the target aiming point. Repeat this process until the desired
point of impact is obtained.
(b) When adjusting, move the azimuth or elevation adjustment
actuator one click to move the strike of the round .5 inch at 50 meters.
One click of adjustment will move the reticle about one square on the
Canadian bull-type target.
NOTE: The lens cover with the peephole may be required to prevent
scope washout from the muzzle flash.
(4) Dismount the sight. The gunner dismounts the sight from the
bracket first by loosening the lever screws. Then he lifts the sight from the
bracket. He must then dismount the bracket in the reverse mounting
procedure.
5-14. TEN-METER FIRING EXERCISE
The purpose of 10-meter firing is to develop skills in the delivery of initial
burst on target. When conducted properly, it will train gunners in the basic
skills, such as 10-meter zero, controlled bursts, traverse, and traverse and
search firing techniques. (See for details on setup and
conduct of firing.)
5-15. TRANSITION DAY FIRING EXERCISE
Transition day firing of the M2 machine gun will teach the gunner some
techniques of fire that he may encounter in combat situations. The gunner
wil field zero his weapon and engage point and area targets from the
tripod-mounted firing position. Within this training, the gunner will be
required to apply all the fundamentals of gunnery learned in preparatory
gunnery training and 10-meter firing. (See for details on the
setup and conduct of transition day fire.)
5-16. NBC FIRING
Since NBC plays an important part in our preparation for war on the
modern battlefield, it is important that each soldier is prepared to
accomplish the mission even if the area is contaminated and he must wear
protective gear. (See[ Appendix d for details on setup and conduct of fire.)
5-17. NIGHT FIRE EXERCISE
The night fire exercise gives the soldiers the practical application of
engaging targets using the AN/TVS-5 at night or during limited visibility.
(See[ Appendix Д for details on setup and conduct of fire.)
Section IV. ADVANCED GUNNERY
After firing 10-meter, day, NBC, and night, gunners need practice in
applying what they have learned. They also need experience in engaging
targets that depict realistic enemy formations. Advanced gunner exercises
provide this experience in mounted, mounted NBC, and predetermined
firing exercises.
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5-18. OBJECTIVES
The objectives of the advanced gunnery phase are to prepare the gunners
for combat. During this phase, training should be directed toward —
* Tracking and leading.
* Mounted target engagement techniques.
* Mounted NBC engagements.
* Predetermined fire techniques.
5-19. TRACKING AND LEADING EXERCISES
The gunner normally completes instruction in firing at stationary targets
before he receives instruction in firing at moving targets. The technique of
engaging a moving target differs from that of engaging a stationary target.
The gun must be aimed ahead of the moving target a sufficient distance to
cause the bullet and target to arrive at the aiming point at the same time.
The distance is measured in target lengths. One target length as seen by
the gunner is one lead. Leads are measured from the center of mass. The
lead depends upon range, speed, and direction of movement of the target.
To hit the target, the gunner aims at a point ahead of the target equal to
the estimated number of leads, maintains the lead by tracking the target
(manipulating the gun at the same angular speed as that of the target), and
then fires. Fire is adjusted by observation of strike/tracer (Figure 5-36).
Figure 5-36. Lead technique.
a. Tracking. Tracking consists of maintaining correct alignment of the
sights (with or without a lead) on a moving target by moving the gun at the
same angular speed as that of the target.
(1) The gunner is required to aim at a prescribed point (center base to
take advantage of the beaten zone) on the target and maintain that aim
during uniform movement of the target. As instruction progresses, speeds
used should differ for successive runs of the target. The speeds the
10-meter targets should move to represent speeds at various ranges are
shown in Table 5-2.
TARGETS SPEEDS IN MILES | TARGET SPEEDS IN INCHES PER SECONDS
PER HOUR CORRESPONDING ТО –
Table 5-2. 10-meter moving target.
(2) The target handler must have practice in moving the target
silhouette across the background at the varying speeds.
b. Leading. Mathematical computation or use of voluminous lead
tables to obtain exact leads on a moving target are impractical in combat.
The simple lead table shown in Table 5-3 gives the amount of lead
necessary to hit a target moving at right angles (90 degrees) to direction to
hit at speeds and ranges indicated.
SPEED IN MILES PER HOUR RANGE OF TARGET
300 M 900 M
. 1/2 target 2 target
length lengths
Table 5-3. Lead table.
(1) The gunner must correct the lead as conditions change. If the
target speed is 7 1/2 miles per hour, the amount of lead is half that shown
in the table; at 30 miles per hour, double that shown, The angle at which
the target is moving also alters the amount of lead taken. If the angle
between line of fire and line of travel of the target is less than 45 degrees,
use half the lead shown in the table.
(2) For targets moving directly toward the gun, the point of aim is
placed on the center or the lower edge of the target, when possible. For
targets moving directly away from the gun, the point of aim is placed on
the center or upper edge of the target. Too much lead is better than too
FM 23-65
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little because the target runs into the fire; also, the observation of strike is
easier. Intelligent use of the lead table includes immediate application of
fire with estimated lead followed by necessary corrections based upon
observation of strike/tracer.
c. Tracking and Leading. Combined tracking and leading exercises at
10 meters are used to gain proficiency in tracking the target. The gunner is
required to repeat the tracking exercise while using a designated lead to
simulate firing when his sights are properly aligned. As a further exercise
in tracking and leading, the gunner may be required to track and lead
moving targets at greater ranges. A vehicle can be run at right angles to
the line of aim at ranges between 500 and 1,000 yards, and at varying
speeds, averaging 15 miles per hour (Figure 5-37).
Figure 5-37. Aiming target used in tracking and leading exercise.
d. Conducting the Lead Exercise (10-Meter). The gunner is required
to take a position at the gun, swing through the target's silhouette, and aim
at a point ahead of the target equal to the prescribed lead from the center
of mass. The gunner then directs the target handler to move the marking
silhouette until the center of the target is at the point of aim. He repeats
this procedure three times for each target lead announced. The target
handler places his marking silhouette on the blank background, traces
around it, and holds it in place for the gunner to aim, using the prescribed
leads. Following the gunner's instructions, he moves the marking
silhouette until the gunner commands HOLD. He then places a pencil dot
at this point and returns the silhouette to the original position. This
procedure is followed until the gunner has completed three tries for each
target lead announced. The three pencil dots for each target should fit
within a one-centimeter circle. The exercise should be conducted for
varying left and right leads.
5-20. MOUNTED FIRING EXERCISE
The purpose of the mounted firing exercise is to teach the gunner
techniques of firing the M2 MG from a mounted platform and to develop
the gunner's ability to fire the M2 with it mounted on its primary carrier.
(See[ Appendix Д for details on the setup and conduct of fire.)
5-21. MOUNTED NBC FIRING EXERCISE
The probability of fighting mounted in a tactical environment that has
been contaminated by NBC agents is very likely; therefore, gunners must
be trained to engage targets while in a mounted NBC posture. (See
for details on the setup and conduct of fire.)
5-22. PREDETERMINED FIRING EXERCISE
The predetermined firing exercises are designed to instruct the gunners on
preparing and using range cards during any visibility conditions. (See
for details on setup and conduct of fire.)
FM 23-65
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CHAPTER 6
COMBAT TECHNIQUES OF FIRE
Technique of fire is the method of delivering and controlling
fire Each member of the machine gun crew must be trained in
standard methods of applying fire, either as a crewmember or
a gunner, and must perform his assigned task automatically
and effectively. The simplest and most effective technique of
delivering fire with the machine gun mounted on its ground or
vehicular mount is to align the sights of the gun on the target
and fire; this is called direct laying. At times, techniques of fire
other than direct laying are more appropriate and effective.
When delivering overhead fire or fire from position defilade,
the gunner must use the appropriate technique.
Section 1. FUNDAMENTALS
Before the machine gun can be employed to the best advantage using any
firing technique, certain fundamentals must be understood and applied.
These include:
* Characteristics of fire.
* Classes of fire.
* Fire control.
* Target types and methods of engagement.
Overhead fire.
Methods of laying the gun.
Firing from position defilade.
Final protective fires.
6-1. CHARACTERISTICS OF FIRE
The gunner's knowledge of his machine gun is not complete until he
learns something of the action and effect of the projectiles when fired.
This section discusses various characteristics of machine gun fire,
including trajectory, cone of fire, and the beaten zone.
a. Trajectory. The trajectory is the curved path of the projectile in its
flight from the muzzle of the weapon to its impact. The major factors that
influence the trajectory are the velocity of the round, gravity, rotation of
the round, and resistance of the air. The farther the round travels, the
greater the curve of the trajectory. The highest point of the trajectory is
called the maximum ordinate. This is a point approximately two-thirds of
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the distance from the gun to the target. The maximum ordinate increases
as the range increases (Figure 6-1).
1,500 M
Figure 6-1. Maximum ordinates at key ranges.
b. Cone of Fire. When the weapon is fired automatically in bursts, all
the rounds do not follow the same path. This is due to the vibrations of
the gun and mount, variations in ammunition, and atmospheric conditions,
which cause the rounds to follow a slightly different trajectory. This group
of trajectories formed by a single burst is called the cone of fire
(Figure 6-2).
Figure 6-2. Cone of fire.
c. Beaten Zone. The beaten zone is an elliptical pattern formed by the
cone of fire as it strikes the ground. The beaten zone is always about
2 meters in width.
(1) Effect of range. As the range to the target increases, the beaten
zone becomes shorter and wider.
(2) Effect of terrain. The length of the beaten zone for any given range
will vary according to the slope of the ground. On rising ground, the
beaten zone becomes shorter but remains the same width. On ground that
slopes away from the gun, the beaten zone becomes longer but remains
the same width.
6-2. CLASSES OF FIRE
Machine gun fire is classified with respect to the ground page
6-4), the target page 6-5), and the gun page 6-7).
a. Classes of Fire with Respect to the Ground.
(1) Plunging fire. Fire in which the angle of fall of the rounds (with
reference to the slope of the ground) is such that the danger space is
confined to the beaten zone, and the length of the beaten zone is
materially shortened. Plunging fire is obtained when firing from high
ground to low ground, when firing from low ground to high ground, and
when firing at long ranges.
(2) Grazing fire. Grazing fire is fire in which the center of the cone of
fire does not rise more than one meter above the ground. When firing
over level or uniformly sloping terrain, the maximum extent of grazing fire
obtainable is about 700 meters.
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; I—————- 700M — E
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GRAZING
Figure 6-3. Classes of fire with respect to the ground.
b. Classes of Fire with Respect to the Target.
(1) Frontal. The long axis of the beaten zone is at a right angle to the
long axis of the target.
(2) Flanking. Fire is delivered against the flank of a target.
(3) Oblique. The long axis of the beaten zone is at an angle (but not a
right angle) to the long axis of the target.
(4) Enfilade. The long axis of the beaten zone coincides or nearly
coincides with the long axis of the target. This class of fire is either frontal
or flanking. It is the most desirable class of fire with respect to the target
because it makes maximum use of the beaten zone.
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^
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^.
б
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Pr Te
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FRONTAL OBLIQUE
FLANKING
FRONTAL
FLANKING ENFILADE
DIRECTION OF MOVEMENT BEATEN ZONE
Figure 6-4. Classes of with respect to the target.
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c. Classes of Fire with Respect to the Gun.
(1) Fixed fire. This is fire delivered on a point target with little or no
manipulation needed. After the initial burst, the gunners will follow any
change or movement of the target without command.
(2) Traversing fire. This is fire distributed against a wide target
requiring successive changes in the direction of the gun. When engaging a
wide target requiring traversing fire, the gunner should select successive
aiming points throughout the target area. These aiming points should be
close enough together to ensure adequate target coverage; however, they
need not be so close as to be wasteful of ammunition by concentrating a
heavy volume of fire in a small area. Two clicks on the traversing
handwheel after each burst ensure coverage (2 clicks = 2 mils = constant
width of beaten zone).
(3) Searching fire. This is fire delivered against a deep target or a
target that has depth, requiring changes in elevation of the gun. The
amount of elevation change depends upon the range and slope of the
ground.
(4) Traversing and searching fire. This is fire delivered both in width
and depth by changes in direction and elevation. It is employed against a
target whose long axis is oblique to the direction of the fire.
(5) Swinging traverse. This is employed against targets that require
major changes in direction but little or no change in elevation. Targets
may be dense, wide, in close formations moving slowly toward or away
from the gun, or vehicles or mounted troops moving across the front. The
traversing slide lock lever is loosened enough to permit the gunner to
swing the gun laterally.
(6) Free gun. This is when fire is delivered against moving targets that
must be rapidly engaged with fast changes in both direction and elevation.
Examples are aerial targets, vehicles, mounted troops, or infantry in
relatively close formations moving rapidly toward or away from the gun
position. To fire free gun on the M3 tripod mount, remove the T&E
mechanism from the receiver and traversing bar and put it down. When
firing swinging traverse and free gun, the weapon is normally fired at the
cyclic rate of fire which is in excess of 450 rounds per minute. This
consumes a lot of ammunition, and there is no beaten zone because each
round seeks its own area of impact.
TRAVERSE TRAVERSE
AND SEARCH
OP
,
‘oa
Г
11
wy,
/
i!
/
l;
I7
i
I
Џ
v
SWINGING
TRAVERSE
FREE GUN
Figure 6-5. Classes of fire with respect to the gun.
Section Il. FIRE CONTROL
Fire control of machine guns includes all operations connected with the
preparation and actual application of effective fire on a target. It implies
the-ability of the leader to-open fire at the instant he desires, to adjust the
fire of the gun(s) on the target, to regulate the rate of fire, to shift from
one target to another, and to cease firing. This ability to exercise proper
fire control depends primarily on the discipline and the proper training of
the crew. Failure to exercise fire control results in danger to friendly
troops, loss of surprise, premature disclosure of positions, application of
fire on unimportant targets, loss of time in adjusting fire, and waste of
ammunition.
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6-3. METHODS OF FIRE CONTROL
Of the several methods of controlling machine gun fire, the noise of battle
will limit the use of some. Therefore, the leader must select the method or
combination of methods that will best accomplish his purpose. The chain
of fire control begins with the leader. He is responsible for both the
technical and tactical employment of the gun and the training of the crew.
He is responsible for passing on to the crewmembers all instructions and
orders from his next higher leader regarding the situation and mission. He
assigns sectors of fire and firing positions, designates targets to be
engaged, adjusts fire, and ensures effective coverage of the targets.
a. Oral. Oral control is effective unless the leader is too far away from
the gun crew(s), or the noise of battle makes it impossible for the gun
crew(s) to hear him.
b. Arm-and-Hand Signals. This is an effective method when the gun
crew(s) can see the leader. All crewmembers must understand the
standard arm-and-hand signals used to control machine gun fire.
c. Prearranged Signals. These are either visual or sound signals such
as pyrotechnics or blasts on a whistle. These signals should be included in
the units’ SOPs and must be clearly understood by all crewmembers.
d. Personal Contact. In many situations, the leader must move to
individual crewmembers to issue orders. This method is used more than
any other by small-unit leaders. The leader must use maximum cover and
concealment to keep from disclosing the gun crew’s position.
e. Standing Operating Procedures. SOPs cover actions the gun crews
perform without command because they were developed and practiced
during the training of the gun crews. Their application eliminates many
commands and simplifies the leader’s job of fire control.
6-4. TARGETS AND THEIR ENGAGEMENT
Targets presented to the machine gunners during combat will in most
cases consist of enemy soldiers in various formations, which require
distribution and concentration of fire. These targets have width and depth,
and the application of machine gun fire is designed to completely cover
the area in which the enemy is known or suspected to be. These targets
may be easy to see or may be indistinct and difficult to locate.
a. When machine gun fire is under direct control of a leader, he
designates the midpoint and flanks or ends of a target unless they are
obvious to the gun crew(s). When a target other than a point target is
engaged by two gunners, it is always divided. Each gunner applies his fire
to that portion of the target corresponding to his position with relation to
the other gun. Normally, each gunner engages one-half of the target;
however, gunners must be prepared to engage the entire target if
necessary. Gunners continue to fire on the target until it is neutralized or
until another signal is received from the leader.
b. The gunner's positions (including vehicular-mounted) should be
numbered so each gunner will know which portion of a target he should
engage. It should be emphasized that the positions are numbered — not the
guns or gunners. To ensure that gunners react quickly and properly when
they detect a target or when a target is designated by the leader, standard
methods of applying fire to the various type targets are taught. These
methods are the same for ground and vehicular-mounted guns. The
following are the different types of targets and how they are engaged with
the MG.
(1) Point targets are targets that require the use of a single aiming
point Enemy bunkers, weapon emplacements, vehicles, small groups of
soldiers, and aerial targets such as helicopters or descending paratroopers
are examples of point targets. A point target is engaged with fixed fire. If
the target moves after the initial burst, the gun crew(s) keeps fire on the
target by following its movement with the gun(s).
(2) Linear targets have sufficient width to require traversing fire and
no more depth than can be effectively covered by the beaten zone. Linear
targets are engaged with traversing fire.
(a) Two guns, normal division. The target is divided at the midpoint;
the right gun engages the right half of the target, and the gun on the left
engages the left half of the target. The point of initial lay and adjustment
for both guns is at the midpoint of the target. After adjusting on the
midpoint, the right gun traverses the right half of the target to include one
aiming point beyond the last visible target flank and returns to the
midpoint.
(b) Two guns, special division. If one portion of the target presents a
greater threat than another, the target can be divided so fire is
concentrated on that portion presenting the greatest threat. The special
division of the target is accomplished by a subsequent fire command after
firing begins. The gunners initially lay at the midpoint, regardless of the
special division to be made, thus precluding confusion.
(c) One gun. A single gunner must engage the entire width of a linear
target. The point of the initial lay and adjustment is on the midpoint, or
that portion of the target presenting the greatest threat. The gunner
traverses to either flank and then covers the remainder of the target
page 6-10).
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Figure 6-6. Linear target and one gun.
(3) Linear targets with depth are targets that have sufficient width to
require traversing fire and depth which cannot be covered by the beaten
zone. A combined change in direction and elevation (traversing and
searching fire) is required to maintain effective fire on these targets
(Figure 6-7). Linear targets with depth are engaged with traversing and
searching fire. When range is announced, the range to the midpoint is
given.
Figure 6-7. Linear target with depth.
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(a) Two guns. The method of division, the point of initial lay and
adjustment, and the extent of manipulation for both guns are the same as
prescribed for linear targets. The gunners, however, apply enough search
between each burst to ensure the center of the beaten zone is maintained
at the center base of the target (Figure 6-8).
(b) One gun. A single gunner initially lays and adjusts on the midpoint
of a linear target with depth unless some other portion of the target
presents a greater threat. The gunner traverses and searches to the near
flank, then he covers the entire target area (Figure 6-8).
(4) Deep targets have depth but very little width and can be effectively
covered by searching fire page 6-12). When the range is
announced, it is given to the midpoint of the target.
Figure 6-8. Engagement of linear targets with depth.
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6-12
Figure 6-9. Deep target.
(a) Two guns. The point of initial lay of both guns is on the midpoint,
which is also the point of division. Since enfilade fire is delivered, it is not
necessary to adjust on the midpoint of the target because the long axis of
the beaten zone will compensate for missing the midpoint. However,
should the gunner's beaten zone be out of the lateral confines of the
target, it will be necessary to adjust fires into the target area. After the
initial bursts, the right gun searches to the near end of the target, and the
left gun searches to the far end of the target. Both gunners then reverse
their direction of search and return to the midpoint [Figure 6-10].
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(b) One gun. А single gunner initially lays and fires at the midpoint of
a deep target, unless another portion of the target presents a greater
threat. The gunner immediately searches to the near end, then covers the
entire target (Figure 6-10).
|
|
i
|
/ ;
(1) РА!В (2) SINGLE
Less than 1,000
Figure 6-10. Engagement of deep targets.
(5) Area targets as discussed in this manual have considerable width
and depth, and they require extensive traversing and searching fires. This
type target exists when the enemy is known to be in a certain area, but his
exact location is not known. A hilltop is a typical area target. The leader
designates an area target by indicating to the gun crew(s) the width and
depth of the target.
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(a) Two guns. The target is divided at the center of mass; the right gun
fires on the right half and the left gun fires on the left half. The point of
initial lay and adjustment for both guns is on the center of mass. After
adjusting on the center of mass, fire is distributed by determining the size
of the beaten zones and applying direction and elevation changes that
cause the most effective coverage of the target area. Both guns traverse
and search their respective halves to the flanks, then return to the
midpoint (Figure 6-11).
(b) One gun. A single gunner engages an area target by laying and
adjusting on the center of mass, traversing and searching to either flank,
then reversing the direction, traversing and searching to the other flank
(Figure 6-11).
PAIR |
| Greater than 50 mils wide SINGLE |
6-14
Figure 6-11. Engagement of area targets (objective).
NOTE: After the target is engaged in whatever formation it is in, the
configuration of that target will change. The gunner must be
trained to compensate for this change and still place effective
fire on the target.
6-5. OVERHEAD FIRE
Overhead fire is fire delivered over the heads of friendly troops. A
machine gun on a tripod is capable of delivering this type of fire because
of the small and uniform dispersion of the cone of fire. In the attack, the
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use of overhead fire permits the machine gun to support the advance of
rifle units. Sectors of fire allow the trainers to plan safe training while still
incorporating the combat realities of overhead fires.
a. Minimum Clearance. The center of the cone of fire must clear the
heads of the friendly troops by a prescribed distance (Figure 6-12). This
distance, known as minimum clearance, is found by adding together the
following elements:
* The height of a standing man, taken as 1.8 meters.
* Half the vertical dimension of the 100-percent cone of fire at the
range to the troops.
* A margin of safety equal to the vertical distance which extends a
5-mil angle at the gun or 3 meters, whichever is greater.
* An additional allowance to compensate for a 15-percent error in
range determination.
TRAJECTORY GIVING 1/2 VERTICAL DIMENSION 100% CONE
MINIMUM CLEARANCE M N
SAFETY MARGIN 5 MILS OR 10 FT
чы А
15% ERROR IN RANGE ESTIMATION
EIGHT OF MAN 6 FT
TRAJECTORY TO TROOPS НЕСИТЕ
li ин!!! ШЕШ
Figure 6-12. Components of minimum clearance.
b. Safety Angles. To obtain this minimum clearance, the gun is
elevated so that the center of the cone of fire is raised from the feet-of the
friendly troops to maintain clearance above their head. The amount of this
elevation change is known as the safety angle. When the gun is fired from
the tripod with the required safety angle, the center of impact determines
the shortest range at which fire can be delivered over the heads of friendly
troops. The range from the gun to the point of strike is called the
corresponding range. When the ground is level or uniformly sloping
between the gun and the target, the corresponding range for the safety
angle used is obtained by converting the angle of elevation expressed in
mils into range.
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c. Conditions. Overhead fire is used only when the following
conditions have been met:
(1) The safety limit has been determined and has been identified on
the ground.
(2) The gun mount is firmly seated.
(3) Friendly troops have been notified, if at all possible, that fire is to
be delivered over them.
(4) The rate of fire does not exceed 40 rounds per minute.
(5) The gun barrel is not badly worn. This condition is indicated by
excessive muzzle blast.
d. Uneven Terrain. Level or uniformly sloping ground is seldom found
in the field. This limits the use of firing tables and corresponding ranges in
determining the limit of troop safety. In lieu of firing tables, a rule of
thumb has been devised to give the gunner a simple method of checking
for troop safety.
(1) The gunner's rule can be applied when the friendly troops are at
least 350 meters in front of the gun position, and the range to the target is
850 meters or less (Figure 6-13).
(a) Lay the gun on the target with the correct sight setting to hit the
target.
(b) Without disturbing the lay of the gun, set the rear sight at a range
of 1,600 meters.
(c) Look through the sights and notice where the new line of aim
strikes the ground. This is the limit of troop safety. When the feet of the
friendly troops reach this point, fire must be lifted or shifted.
CENTER OF CONE OF FIRE
LINE OF AIM AT 1500
TROOPS
850 METERS
Figure 6-13. Application of gunner's rule.
ЕМ 23-65
(2) When the range to the target is greater Шап 850 meters, overhead
fire should be delivered only in an emergency and then only out to a range
in which either the tracers or the strike of the bullets can be seen by the
gunner. In this situation the leader's rule applies (Figure 6-14).
CENTER OF CONE OF FIRE TARGET
NEW LINE OF AIM
SELECTED POINT
[ —————— 1000 METERS —________] |
1——————————— 1500 METERS
Figure 6-14. Application of leader's rule.
The platoon or section leader uses the leader's rule only when the target is
greater than 850 meters. The rule is as follows:
(a) Select a point on the ground where it is believed friendly troops
can advance with safety.
(b) Determine the range to this point by the most accurate means
available.
(c) Lay the gun on the target with the correct sight setting to hit the
target.
(d) Without disturbing the lay of the gun, set the rear sight to
1,600 meters, or the range to the target plus 500 meters, whichever is
greater. Under no conditions should the sight setting be less than 1,500
meters.
(e) Note the point where the new line of aim strikes the ground.
* [f it strikes at the selected point, that point marks the limit of
safety.
* [f it strikes short of the selected point, it is safe for troops to
advance to the point where the line of aim strikes the ground
and to an unknown point beyond. If it is desired to fire after
friendly troops advance farther than the point where the line
of aim strikes the ground, this farther point is determined by
testing new selected points until the line of aim and the selected
point coincide.
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ЕМ 23-65
* If it clears the selected point, it is safe for the troops to advance to
the selected point and to an unknown point beyond. If it is desired
to have troops advance beyond the selected point, this farther
point must be determined by testing new selected points until the
line of aim and the selected point coincide. This point marks the
line of safety.
e. Precautions. The following safety precautions must be observed in
delivering overhead fire.
(1) Firmly emplace the tripod mount.
(2) Use depression stops to prevent the muzzle of the gun from
accidentally being lowered below the safety limit.
(3) Do not deliver overhead fire through trees.
(4) Inform commanders of friendly troops when fire is to be delivered
over their heads.
(5) Ensure that all members of the gun crew(s) are aware of the safety
limit.
(6) Do not deliver overhead fire if the range from the gun to the
target is less than 350 meters or more than 850 meters.
(7) Do not use a barrel that has excessive muzzle blast or 1s otherwise
determined to be badly worn.
(8) Do not lay machine guns so their fire will cross at any point over
the heads of friendly troops.
6-6. DEFILADE POSITIONS
To achieve maximum effectiveness, the machine gun must be employed
using the technique of direct lay; however, at times it may be desirable to
employ guns from defilade positions.
a. Full Defilade. A machine gun is in defilade when the gun and its
crew are hidden from enemy ground observation by a land mass such as
the crest of a hill. The position may be on the reverse side of the crest or
the forward slope of the next higher ground (Figure 6-15). The gun must
fire up and over the hill. Fire must be observed and adjusted by a
crewmember who can observe the target from a position on a flank or to
the rear of the gun (on higher ground). A defilade position allows little
opportunity to engage new targets.
b. Partial Defilade. A machine gun is in partial defilade when a mask
(usually the crest of a hill) provides the gun and gunner with some
protection from enemy direct fire, but the gunner is able to engage the
target using direct laying techniques. The gun is far enough up the slope so
that the gunner can see the target through the sights but the lower portion
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ЕМ 23-65
of his body and lower portion of the gun are protected by the mask. Partial
defilade positions are desirable when a fire mission cannot be
accomplished from a defilade position.
c. Advantages. The gun and crew have cover and concealment from
direct fire weapons. The crew has some freedom of movement in the
vicinity of the gun position, and control and supply are facilitated. The
characteristic smoke and flash of the gun are partially concealed from
observation.
d. Disadvantages. Rapidly moving ground targets are not easily
engaged because adjustment of fire must be made through an observer.
Targets close to the mask usually cannot be engaged, and it is difficult to
secure grazing fire for a final protective line.e.
e. Position Selection. The fire unit leader selects the location of the
gun position. To select a position in partial defilade, he moves up the
reverse side of the slope until he has the target in view above the mask
when sighting at the height of the gunner's eye. To select a position in
maximum defilade, he estimates the lowest point below the mask at which
the gun can still engage the target without danger of hitting the mask.
DIRECT LAY
EXPOSED POSITION DEFILADE
POSITION (FORWARD SLOPE)
MAXIMUM
POSITION MINIMUM POSITION DEFILADE
ARTI БЕГ ДОР (REVERSE SLOPE)
DEFILADE |
Hy / у) д
| ү
Min
_
:
К
Figure 6-15. Minimum and maximum position defilade,
partial defilade, and direct lay areas.
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6-20
6-7. METHODS ОЕ LAYING THE GUN FOR DEFILADE FIRING
The essential elements in engagement of a target from defilade position
are direction, elevation, mask clearance, and adjustment of fire.
a. Direction. An observer places himself on the gun-target line in a
position from which he can see the gun and the target. He aligns the gun
approximately by having the gunner shift the mount. The gunner then
loosens the traversing slide lock lever and, as directed by the observer,
moves the gun right or left until it is aligned on the target; he then clamps
it in that position. A prominent landmark, visible to the gunner through
his sights, is selected as an aiming point. An aiming point on the gun-target
line and at an equal or greater range than the target is desirable. However,
an aiming point on the mask may be used. If the aiming point is on the
gun-target line, the gun is laid on the aiming point and is thereby aligned
for direction. If the aiming point is not on the gun-target line, the
deflection is measured by binoculars or compass. This measured
deflection is laid off with the gun.
b. Elevation. An aiming point visible from the gun position is selected
(preferably a point at a greater range and at a higher elevation than the
target) and the range to the target is determined. The leader, using
binoculars, measures the vertical angle in roils from the aiming point to
the base of the target. He then lays the gun on the aiming point with the
sight set to hit the target. He directs the gunner to manipulate the gun
through the number of mils measured. For example, in| Figure 6-16] the
range to the target is 1,300 meters. The angle read with the binoculars
from the aiming point down to the base of the target is 12 mils. The sight is
set at 1,300 meters, the gun laid on the aiming point, and the muzzle
depressed 12 mils. If the aiming point is off the gun-target line, deflection
in mils may be taken with the rear sight windage screw knob if it is not
over 5 mils; otherwise, the deflection must be taken up on the traversing
handwheel.
c. Mask Clearance. After the gun has been laid, determine if the
entire cone of fire will clear the mask.
(1) Visual method. When the range to the mask is not more than
450 meters, mask clearance exists when the axis of the bore is elevated
7 mils or more above the gun-mask line. Mask clearance can be checked
after the gun has been laid on the target by depressing the muzzle of the
gun 2 mils and sighting along the bottom of the receiver and the barrel
support. If this line of sight clears the mask, the clearance exists. Elevate
2 mils before firing.
(2) Firing tables method. Determine the range to the mask and obtain
the corresponding angle of elevation for mask clearance from the firing
tables. The range corresponding to the angle of elevation is set on the gun
sight. If the line of aim through the sight clears the mask, the clearance
exists.
d. Adjustment of Fire. Under field conditions, even the most practical
methods of laying the gun on the target quickly do not always result in the
initial burst being on the target. For this reason, adjustment of fire on the
target is essential. Creeping fire should be avoided. (See| paragraph 6-10
for details on adjustment of fire.)
AIMING POINT
AXIS OF BORE
12 MILS
ntis 1300 METERS
TARGET
al
SS Mm ЛП
-O o [3
Figure 6-16. Aiming point method.
6-8. FINAL PROTECTIVE FIRES
These are types of fire that are placed on a predetermined line along
which grazing fire is placed to stop an enemy assault. This fire is fixed in
direction and elevation; however, a few roils of search are employed
during firing to compensate for irregularities in the terrain. FPLs are
always laid in using the extreme left or right of the tripod, causing the
T&E to move to the extreme left or right on the traversing bar. The FPFs
can be delivered in any visibility conditions. When terrain permits, final
protective lines are assigned to machine guns along the forward line of
troops as a part of the FPFs of the defending unit. The signal used to call
for FPFs is normally prescribed in the company operation order. The
FM 23-65
ЕМ 23-65
6-22
authority to call for these fires may be delegated to the platoon leader of a
forward rifle platoon. Final protective fires are ceased on order.
a. Signals. Arm-and-hand signals, voice commands, or pyrotechnic
devices may be used in calling for these fires.
b. Rates of Fire. When firing FPFs, the rapid rate of fire is used unless
it is obvious that a different rate is necessary to accomplish the mission.
When engaging other preselected target areas, the rapid rate of fire is
used until commanded to cease fire.
6-9. APPLICATION OF FIRE
To be effective, machine gun fire must be distributed over the entire
target area. Improper distribution of fire results in gaps which allow the
enemy to escape or use weapons against friendly positions without
effective opposition.
a. The method of applying fire to a target is generally the same for
either a single gun or a pair of guns. Direct laying is pointing the gun for
direction and elevation so that the sights are aligned directly on the target.
Fire is delivered in width, depth, or in a combination of the two. To
distribute fire properly, the gunners must know where to aim, how to
adjust their fire, and the direction to manipulate the gun. The gunner must
aim, fire, and adjust on a certain point of the target. Binoculars may be
used by the leader to facilitate fire adjustment.
b. The gunner ensures throughout his firing that the center of the
beaten zone is maintained at the center base of the target for maximum
effect from each burst of fire. When this is done, projectiles in the upper
half of the cone of fire will pass through the target if it has height, and the
projectiles in the lower half of the beaten zone may ricochet into the
target (Figure 6-17).
c. The gunner must move his beaten zone in a certain direction over
the target. The direction depends on the type of target and whether the
target is engaged with a pair of guns or a single gun. When engaging
targets other than point targets with a pair of guns, the targets are divided
so that fire is evenly distributed throughout the target area. Fire delivered
on point targets or a specific area of other target configurations is called
concentrated fire.
ЕМ 23-65
UPPER HALF OF СОМЕ OF FIRE
PASSING THROUGH TARGET
LINE OF AIM
LOWER HALF OF BEATEN ZONE
RICOCHETING INTO TARGET
Figure 6-17. Line of aim and placement of center
of beaten zone on target.
6-10. FIRE ADJUSTMENT
Machine gun fire is adjusted by observing the strike of the rounds,
observing the flight of tracers, frequently re-laying the gun, or by a
combination of these. Adjustment by observation of fire is the most
important element of fire control if it is bold, aggressive, rapid, and
continuous throughout the action.
a. The gunner is trained to observe and adjust his gun's fire without
command. He is trained to anticipate the action of the enemy after the
initial burst, and is prepared to shift his fire to cover any change in
formation or movement of his target. If the gunner fails to accomplish this,
the fire unit leader must promptly correct him by announcing or signaling
subsequent fire commands. This responsibility to adjust fire continues
through the chain of commands.
b. When subsequent fire commands are given, the gunner makes the
required corrections and continues to engage the target without any
further command to fire. If the gun is fired on the tripod mount,
subsequent commands are given to make changes in direction, elevation,
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6-24
and the rate of fire. These changes are given orally as SHIFT RIGHT,
SHIFT LEFT, ADD, or DROP. (For arm-and-hand signals see
FM 21-60. When making these announced changes,mils may be used to
indicate the amount of desired shift; for example, SHIFT RIGHT 5 or
SHIFT LEFT 7. When making changes in elevation, roils are not used, as
it is normally difficult to determine just how high or low the center of the
beaten zone is striking the ground in relation to the target.
(1) Observation. When firing on the 10-meter range, the strike of the
bullets is visible on the target. When firing at greater distances, the strike
of the bullets on the ground may cause dust to rise, which is visible to the
gunner; however, during wet weather the strike cannot always be seen. In
this event, the tracers will allow the gunner or crew leader to note the
strike of the burst in relation to the target.
(2) Adjustment. Using the mil relation, one click of the traversing
handwheel or elevating handwheel moves the strike of the bullet 1/2 inch
on the target at a range of 10 meters.
(a) When firing on the 10-meter range, adjust by moving the shot
group a required number of centimeters vertically or horizontally until the
center of the group is on the aiming paster. Should the gunner's initial
burst strike the target 2 centimeters to the left and 3 centimeters below
the aiming paster, he adjusts his fire by traversing right 4 clicks and
elevating 6 clicks before firing again.
(b) When firing on field targets, adjust by moving the burst into the
target. One click (roil) on the traversing handwheel will move the strike
1/2 meter at 500 meters or 1 meter at 1,000 meters; however, the distance
1 click (roil) in the elevating handwheel will move the strike depends on
the range to the target and the slope of the ground. The gunner
determines the number of roils necessary to move the center of the strike
into the target, and he manipulates the gun the required number of roils.
This does not require the use of sights. For example, should the gunner
fire on a target at 500 meters and observe the strike 10 meters to the right
of the target and short about 50 meters, he would traverse the gun to the
left 20 clicks (roils) and add one or more clicks (roils), depending on the
slope of the ground.
(c) The gunner may use the adjusted aiming point method to adjust
the fire. In this method the gunner must use his sights. He selects an
aiming point that will place the next burst on the target. For example,
should the gunner fire on a target at 500 meters and estimate that the
strike is 20 meters short and 10 meters to the right of the target, he would
rapidly select an aiming point approximately 20 meters beyond the target
and 10 meters to the le
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