Document text
FM 6-70
WAR DEPARTMENT!
FIELD ARTILLERY*
FIELD MANUAL
SERVICE OF THE PIECE
75-MM HOWITZER, HORSE AND
TRUCK-DRAWN
US. Arm; Military History institute
***** fro.
FM 6-70
FIELD ARTILLERY
FIELD MANUAL
SERVICE OF THE PIECE
75-MM HOWITZER, HORSE AND
TRUCK-DRAWN
Prepared under direction of the
Chief of Field Artillery
UNITED STATES
GOVERNMENT PRINTING OFFICE
WASHINGTON : 1939
For sale fcy tile Superintendent of Documents, Washington, D. C.
Priee 10 fonts
WAR DEPARTMENT,
Washington, October 14, 1939.
FM 6-70, Field Artillery Field Manual, Service of the
Piece — 75-ram Howitzer, Horse and Truck-drawn, is pub-
lished for the information and guidance of all concerned,
[A. G. 062.11 (6-17-39).]
BY ORDEH OF THE SECRETARY OF WAR:
G. C. MARSHALL,
Chief of Staff.
Official :
E. S. ADAMS,
Major General,
The Adjutant General.
ii
TABLE OF CONTENTS
Section I. General: Paragraph Page
Purpose and scope 1 1
References 2 1
Definitions and terms 3 1
Section n. Organization:
Composition 4 2
Formation 5 3
Section trl. Posts; mounting and dismounting:
Posts or the howitzer squad 6 4
To post the howitzer squads 7 4
Posts of the cannoneers 8 6
To post the cannoneers 9 6
To mount the cannoneers 10 7
To dismount the cannoneers 11 7
Section IV. Movements of the carriages by hand:
Limbered or coupled 12 8
Unlimbered or uncoupled 13 8
Section V. Unlimbering and limbering:
Unlimbering 14 9
Umbering 15 12
Section VI. Uncoupling and coupling:
Uncoupling 16 13
Coupling 17 14
Section VII. Preparation for action and march order :
To prepare for action . 18 15
Posts of the cannoneers, carriages unlimbered (un-
coupled) 19 18
March order 20 19
Section VTII. Duties in firing:
General 21 22
Chief of section 22 22
Gunner 23 27
No. 1 24 30
No. 2 25 31
No. 3 28 32
No. 4 27 34
No. 5 28 36
Section IX. Additional information on the service of the
piece:
Accuracy in laying 29 38
To fire by individual sections with direct laying at
moving targets 30 38
Fire at will 31 39
Aiming stakes 32 39
Correction for lateral displacement 33 40
Reporting errors 34 40
Cease firing , 35 40
Suspend firing 38 40
Changes in data during firing 37 41
HE
TABLE OF CONTENTS
Seottow IX— Continued, Paragraph Page
To unload the piece 38 41
Misfires 39 41
Ammunition 40 42
The section data board 41 42
Firing from the wheels 42 42
Section X. Care and maintenance of materiel:
General . . 43 42
Cleaning . 44 43
Lubrication 45 45
Protection against chemicals 46 48
Recoil mechanism . 47 48
Tube assembly, breech mechanism, and firing mech-
anism— , 48 50
Wheels and brakes 49 52
Miscellaneous parts of carriage 50 53
Sighting and fire-control equipment 51 54
IV
PM 6-70
FIELD ARTILLERY FIELD MANUAL
SERVICE OF THE PIECE
75-MM HOWITZER, HORSE AND TRUCK-DRAWN
Section I
GENERAL
■ 1, Purpose and Scope. — This manual prescribes the duties
to be performed in the service of the piece by the personnel
normally assigned to one howitzer section of the firing
battery.
■ 2. References. — a. Description, operation, functioning, and
care of materiel — TR 1305-A; TR 1305-75E; SNL C-26;
SNL C-29.
b. Description and operation of fire-control and sighting
equipment.— -TR 1320-C (now TR 310-20) ; SNL P-106; SNL
F-1C6; SNLF-169.
c. Ammunition. — TR 1355-75A; TR 1370-A; SNLR-1; SNL
R-3.
d. Cleaning and preserving materials. — TR 1395-A; SNL
K-l.
e. $founted cannoneer (horse butteries) . — FM 25-5.
/. Field artillery driver. — Part Two, FM 6-5.
g. Maneuvers of the battery.— Text Two, FM 6-5.
h. Safety precautions in firing. — AR 750-10; Chapter 1,.
FM 6-40.
i. Firing battery. — Chapter 1, FM 6-40.
j. Gunnery. — FM 6-40.
k. Reconnaissance, occupation, and organization of posi-
tion. — Part One, FM 6-20.
ta 3. Definitions and Teems. — a. Section. — Tables of Or-
ganization prescribe the personnel and materiel comprising a
1
3-4
SERVICE OF THE PIECE
section of a battery. In this manual the term is frequently
used to designate a section of the firing battery. In this
restricted sense, a howitzer section is composed of one piece
and the additional materiel and the personnel required to
serve that piece.
b. Limbered. — A piece (caisson) is said to be Umbered when
its lunette is attached to the pintle of its limber.
c. Uidwriberetl. — A piece (caisson) is said to be unlimbeTed
when its lunette has been detached from the pintle of the
limber and the trail (caisson prop) rests on the ground.
d. Coupled. — A piece is said to be coupled when its lunette
is attached to the pintle of a truck or other prime mover.
e. Uncoupled. — A piece is said to be uncoupled when its
lunette is detached from the pintle of a truck or other prime
mover and the trail rests on the ground.
/. Front, — The front in a section, carriages limbered or
coupled, is the direction in which the trail points; carriages
unlimbered or uncoupled, the direction in which the muzzle
of the piece points.
g. Right (.left) . — The direction right (left) is the right
(left) of one facing to the front.
h. In battery, — The term "in battery" is used to designate
the position of the howitzer when it is in its normal firing
position.
Section II
ORGANIZATION
• 4. Composition",. — a. HavMzer squad. — A howitzer squad
consists of the gunner and five cannoneers numbered "from
1 to 5. The remaining cannoneers of the howitzer section
act as reliefs or are assigned such other duties as the chief of
section may direct. In horse batteries two, or more if neces-
sary, of the highest-numbered cannoneers are assigned as
horseholders. When the battery unlimbers or uncouples for
drill or for firing, the chief of section remains at the firing
position and commands the howitzer squad.
b. Ammunition squad. — (1) An ammunition squad consists
of an ammunition corporal and cannoneers as prescribed in
Tables of Organization. These cannoneers are numbered
2
SERVICE OF THE PIECE
consecutively, beginning with No. 1, and are assigned to the
ammunition vehicles of the ammunition (fifth) section. In
organizations equipped with caissons, the cannoneers are
equally divided between the two caissons, the lower -num-
bered cannoneers being assigned to the first caisson.
(2) Posts and movements prescribed hereinafter for the
howitzer squad apply, with obvious modifications, to an
ammunition squad.
■ 5. Formation/ — a>. Order of formation. — (1) ZHsmoimted. —
A howitzer squad is formed as shown in figure 1. Higher-
numbered cannoneers, if present, form in order on the left
of No. 5.
1 z 1 1 1 a i
FiGTHiE !• — Formation of the howitzer squad.
C2) Mounted. — A horse howitzer squad is formed as shown
in figure 2. The interval between horses is 18 inches, the dis-
tance between ranks, 4 feet. When more than the gunner and
seven cannoneers are present, three ranks are formed.
b. To form. — (1) Dismounted. — The place of formation is
indicated and the command given thus, for example: 1. in
FRONT (REAR) OF TOUR PIECES (CAISSONS), or 1. ON THE ROAD
facing the park, 2. FALL IN, Each gunner repeats the com-
mand fall in and hastens to place himself, faced in the proper
direction, at the point where the right of his squad is to rest.
The cannoneers move at the double time and assemble at
attention in their proper places. For the first formation of
the howitzer squads for any drill or exercise, the caution, "As
howitzer squads," precedes the command. The chief of
section, if present, supervises the formation.
(2) Mounted. — To form a horse howitzer squad mounted,
the commands are the same as those given above with the
exception that lead out is substituted for the command
fall in. The gunner moves to the point indicated and faces
in the desired direction. The cannoneers lead out, form in
their proper places and STAND TO HORSE.
(3) In case the front or rear of the carriages is designated,
each squad falls in at its post (par. 6) .
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5-7
SERVICE OF THE PIECE
e. To call off. — CI) Dismounted. — The command Is: CALL
OFF. The cannoneer on the left of the gunner calls off "One";
the cannoneer on the left of No. 1, "Two"; and so on.
(2) Mounted. — The command is: CALL OFF. The can-
noneer on the right of the rear rank calls off "One"; the can-
noneer on the left of the gunner, "Two"; the cannoneer on
the left of No. 1, "Three"; and so on. The gunner does not
call off.
(3) After having called off, If a subsequent formation is
ordered, the cannoneers fall in at once in their proper order.
Section in
POSTS; MOUNTING AND DISMOUNTING
fl 6. Posts of the Howitzer Squad. — a. Carriages limbered
iioithout teams), or coupled. — CI) In front of the piece or
caisson. — The squad is in line facing to the front, its center
two paces from the end of the pole or from the front of the
truck.
(2) In rear of the piece or caisson. — The squad is in line
facing to the front, its center two paces from the muzzle of
the piece or from the rear of the caisson.
b. Carriages limbered (.with teams). — (1) When the sec-
tion is in section column, each squad is posted as shown in
figure 2, its front and center 2 yards in rear of the caisson.
(2) When the section is in double section or flank column,
each squad is posted on the outer flank of and 2 yards from
the caisson, the front rank alined on the limbers. When
three ranks are formed (par. 5b (2)), the front rank is
alined on the wheel drivers.
c. Carriages unlimbered or uncoupled. — The squad is in
rear of the piece, in line facing to the front, its front and
center two paces from the end of the trail of the piece.
B 7. To Post the Howitzer Squads. — The squads having
been marched to the vicinity of the carriages are posted at
the command squads in front (rear) of your pieces (cais-
sons) . Each gunner marches his squad to its carriages and
posts it in the position indicated.
4
177139°— 39— 2
5
8-9 SERVICE OF THE PIECE
H 8, Posts of the Cannoneers. — a. Carriages limbered, or
coupled. — The cannoneers are pasted as shown in figures 3
and 4, respectively. All are 2 feet outside the wheels and
facing to the front. Higher-numbered cannoneers, if pres-
ent, are posted as prescribed by the chief of section.
b. Carriages unlimbered. — See paragraph 19,
■ 9. To Post the Cannoneers. — a. The command is : 1. can-
noneers, 2. POSTS. Each gunner repeats the command
Piouhe 4. — Posts of the cannoneers, pieces coupled.
posts. The cannoneers leave the ranks, if formed, and move
at the double time to their posts.
f>. For preliminary instruction, the squads on entering the
park are first posted with their carriages, and the cannon-
eers are then sent to their posts by the foregoing command.
6
SERVICE OF THE PIECE
0-11
The command is general, however, and is applicable when
the cannoneers are in or out of ranks, at a bait or marching,
and when the carriages are limbered (coupled) or unJim-
bered (uncoupled) .
H 10. To Mount the Cannoneers. — a. (1) Horse batteries. —
In each howitzer squad the personnel is mounted as shown in
figure 2.
(2) Truck-drawn, batteries. — In each squad the personnel
is seated in the truck, in the order prescribed by the battery
commander. The chief of section is seated beside the driver.
b. The command is: 1. cannoneers, prepare to mount, 2.
MOUNT.
(1) Horse batteries. — The mounts of the cannoneers are
in charge of horseholders 2 yards in rear or to the flank of
their caissons. At the first command, the cannoneers move
at the double time and prepare to mount. At the second
command, they mount and form as prescribed in a above.
(2) Truck-drawn batteries. — At the first command, the
cannoneers move at the double time to positions on the ground
convenient for mounting the truck. At the second command,
all mount as prescribed by the battery commander,
c. If the command is: 1. cannoneers, 2. MOUNT, the can-
noneers execute at the command mottbt all that has been
prescribed for the commands cannoneers, prepare to mount
and mount.
■ 11, To Dismount the Cannoneers. — a. The command is;
1. cannoneers, prepare to dismount, 2. DISMOUNT.
(1) Horse batteries. — At the first command, the cannoneers
prepare to dismount; at the second command, they dismount
and stand to horse.
(2) Truek-dravm batteries. — At the first command, the
cannoneers assume positions from which they can dismount
promptly; at the second command, they jump to the ground
and take their posts at the double time.
b. If the command is: 1. cannoneers, 2. DISMOUNT, the
cannoneers execute, at the command dismount, all that has
been prescribed for the commands cannoneers, prepare to
dismount and dismount.
7
12-13
SERVICE OF THE PIECE
Section IV
MOVEMENTS OP THE CARRIAGES BY HAND
B 12. Limbered or Coupled. — a. Horse batteries.' — (1) To the
front, — The command is: 1. pieces (caissons) forward, 2.
MARCH, 3. HALT. In each squad at the first command
the gunner and No. 1 hasten to the end of the pole; Nos. 2
and 5 to the rear of the limber chest ; Nos. 3 and 4 to the rear
of the piece (caisson) wheels; higher-numbered cannoneers,
if present, to posts as directed by the chief of section; the
gunner and even numbers working on the right side of the
carriage; odd numbers on the left. When the piece is to be
moved, Nos. 3 and 4 release the brakes. When the caisson is
to be moved, No. 4 releases the brake ; when the brake is re-
leased, Nos. 3 and 4 raise and secure the caisson prop. At the
command march, all assist in moving the carriage to the
front. At the command halt, the carriage is stopped. In the
case of the piece, Nos. 3 and 4 set the brakes. In the case
of the caisson, Nos. 3 and 4 lower the caisson prop and No. 4
sets the brake. All cannoneers resume their posts.
(2) To the rear. — The command is: 1. pieces (caissons)
backward, 2. MARCH, 3. HALT. Executed as prescribed
above, except that Nos. 2 and 5 go to the front of the limber
chest and Nos. 3 and 4 go to the front of the piece (caisson) ,
and at the command march the cannoneers move the carriage
to the rear.
o. Truck-drawn batteries. — The carriages are not moved by
hand when coupled.
■ 13. Unlimeerid on Uncoupled. — The command is: 1. pieces
(CAISSONS) FORWARD (BACKWARD), 2. MARCH, 3, HALT.
a. Piece, — (1) First command. — At the first command,
Nos, 3 and 4 grasp the trail handles. No. 3 on the right and
No. 4 on the left; No. 2 grasps the left wheel and No. 5 the
right wheel; the gunner and No. 1 place themselves adjacent
to their posts, in rear of the axle in moving forward and in
front of the axle in moving backward; higher-numbered can-
noneers, if present, are employed as directed by the chief of
section.
S
SERVICE OF THE PIECE
13-14
(2) Second command. — At the command march, all work-
ing together move the piece forward (backward) under the
direction of the chief of section. When moving up or down
steep slopes, the gunner and No. 1 assist by alternately setting
and releasing the right and left brakes, thus permitting the
piece to be pivoted about the locked wheel. At the command
halt, they stop the piece, the gunner and No. 1 set the biakes,
and all resume their posts (par. 19) .
b. Caisson. — Executed as explained for the piece, except
that No, 4 releases the caisson brake and No. 3, when the trail
is raised, raises and secures the caisson prop. The gunner
and No. 1 are at the rear of the caisson chest when moving
forward and at the front of the caisson chest when moving
backward, the gunner on the left. At the command halt,
No. 3 lowers the caisson prop and No. 4 sets the caisson brake.
All take their posts (par. 19).
Section V
UNLIMBERING AND LIMBERING
S 14. Unlimbering. — a. Bisvosition of the carriages. — (1)
Before unlimbering. — The piece and its'- caisson are placed
abreast of eaeh other, 2 yards apart, poles pointing in the
direction of movement. This formation of the carriages is
called a double section. The interval of 2 yards should not be
materially changed, otherwise the amount of movement of
the carriages by hand is greatly increased. If it is intended
to fire to the front, the caisson should be placed on the left
of the piece before the command for unlimbering is given; if
it is intended to fire to the rear, the caisson should be on the
right of the piece ; if to the flank, on either side of the piece.
In emergencies the carriages may be unlimbered from any
formation.
(2) After unlimbering. — (a) The adjacent wheels of the
piece and the caisson are abreast of each other about 1 foot
apart, trails of the piece and the caisson pointing to the rear,
the piece on the right.
(b) In emergencies the caisson may be placed temporarily
on the right of the piece. As this position is not favorable to
9
14
SERVICE OF THE PIECE
the service of ammunition, the caisson should be moved to
the left of the piece as soon as practicable,
(c) At ceremonies and drills, limbers are posted 25 yards
in rear of their carriages, moving to their post at a trot. In
active service and in instruction simulating it, limbers are
conducted by the first sergeant to a place previously desig-
nated by the battery commander, where they are disposed so
as to take the best advantage of cover and concealment. If
no cover and concealment are available, they are located in
rear of either flank, faced toward the front, with wide
intervals between them.
b. To iinlimber. — (1) General. — In unlimbering, the piece
establishes the position. When the carriages are 25 yards
from the position, the gait is reduced to a walk; cannoneers
other than horseholders dismount, turn their horses over
to the horseholders, and double time to their posts (fig. 3) .
If the carriages, after unlimbering, have to be moved by hand,
each carriage is moved as prescribed in paragraph 13, in
the order designated by the chief of section. If the teams
are not hitched, the carriages are unlimbered successively,
the one which establishes the position being unlimbered
first. Limbers are "moved to their position by cannoneers
designated by the chief of section.
(2) To fire to the front. — The carriages being in double
section, the caisson on the left, the command is: ACTION
FRONT. If marching, the carriages halt at the command
Or signal.
(a) The piece. — The gunner and No. 1 hasten to the trail
handles; No. 2 gTasps the right wheel and places himself
so as to be ready to turn the wheel toward the muzzle; No. 5
grasps the left wheel and places himself so as to be ready to
turn the wheel toward the trail. The gunner unlatches the
pintle and assisted by No. 1 raises the trail from the pintle.
The gunner then commands or signals drive on. The gun-
ner and No. 1 carry the trail away from the caisson, and all
the cannoneers working together turn the piece 180°. The
gunner and No. 1 lower the trail to the ground, and all the
cannoneers at the piece take their posts (pars. 18c and 19) .
(b) The caisson. — Nos. 3 and 4 hasten to the trail han-
dles; No. 4 unlatches the pintle; Nos. 3 and 4 raise the trail
10
SERVICE OF THE PIECE
14
from the pintle, and No. 4 commands or signals drive on.
Nos. 3 and 4, assisted by the higher-numbered cannoneers
at the wheels, then carry the trail away from the piece,
turning the caisson 180°. No. 3, assisted by No. 4, lowers
the caisson prop; No. 4 sets the caisson brake, and Nos. 3 and
4 take their posts. As soon as practicable, the caisson is
placed beside the piece (a, (2) above) .
(e) Limbers. — At the command drive on, the limbers take
their prescribed positions. To take post in rear of the car-
riages, the caisson limber executes a left- about, moves straight
to the rear, executes another left-about, and halts so that
the heads of the lead horses (or the end of the pole if teams
are not hitched) will be 25 yards from the rear of the cais-
son. The piece limber follows the caisson limber, passes
around its rear, and halts so as to be abreast of it and 2
yards to its right.
(3) To fire to the rear. — The carriages being in double
section, caisson on the right, the command is: ACTION
REAR. If marching, the carriages halt at the command
or signal.
(a) The piece. — The gunner and No. 1 hasten to the trail
handles of the piece; No. 2 grasps the right wheel and No.
5 grasps the left wheel of the piece and both stand ready to
assist in such movements of the carriage as may be neces-
sary. The gunner unlatches the pintle and assisted by No.
1 raises the trail from the pintle. The gunner then com-
mands or signals drive on. The gunner and No. 1 lower
the trail to the ground, and the cannoneers at the piece take
their posts (pars. 18c and 19).
(o) The caisson. — Nos. 3 and 4 hasten to the trail handles;
No. 4 unlatches the pintle; Nos. 3 and 4 raise the trail from
the pintle, and No. 4 commands or signals deive on. No, 3,
assisted by No. 4, lowers the caisson prop; No. 4 sets the
brake, and Nos. 3 and 4 take their posts. As soon as prac-
ticable, the caisson is placed beside the piece (a (2) above).
Higher-numbered cannoneers, when present, assist in the
movement as directed by the chief of section.
(c) Limbers. — At the command or signal drive on, the
limbers take their prescribed positions. To take post in rear
of the carriages, the caisson limber inclines well to the right,
11
14-15
SERVICE OF THE PIECE
moves to the rear, executes a left -about, and halts so that the
heads of the lead horses Cor the end of the pole Lf teams are
not hitched) will be 25 yards from the rear of the caisson.
The piece limber follows the caisson limber, passes around its
Tear, and halts so as to be abreast of it and 2 yards to its
right.
(4) To fire to the flank. — (a) The carriages being in double
section, the caisson on either side of the piece, 2 yards from
and abreast of it, the command is: ACTION RIGHT (LEFT).
The movement is executed according to the principles of
action front and action rear, with the Hollowing modifica-
tions: After the carriages are unlimbered, the muzzle of the
piece is turned in the direction of Are and the trail of the
caisson in the opposite direction; the caisson is moved to its
proper position beside the piece (a (2) above).
(E>) At the command or signal drive on, the limbers take
their prescribed positions. To take post in rear of the car-
riages, the limber away from the flank toward which Are is
to be delivered moves out first, wheels away from, the direc-
tion of fire, and after having gained sufficient distance to the
rear executes an about, and halts so that the heads of the
lead horses (or the end of the pole if teams are not hitched)
will be 25 yards from the rear of its carriage. The other
limber follows and takes post in a similar manner.
E 15. Limbering. — a. To limber front and rear,— The car-
riages being in position and in march order (par. 20), the
command is: LIMBER FRONT AND REAR.
(1) Ho. 4 releases the catsson brake and hastens to the
caisson trail; Nos. 3 and 4 raise the trail and when the trail
is raised No. 3 raises and secures the caisson prop. Nos. 3 and
4 working at the trail, all other cannoneers assisting, turn
the caisson 180°, carrying the trail away from the piece, the
gunner and even numbers working on the right and odd
numbers on the left. The movement being completed, Nos.
3 and 4 lower the caisson prop; No. 4 sets the caisson
brake, and the cannoneers take posts for limbering as fol-
lows: The gunner and No. 1 face to the rear at their posts;
No. 2 places himself on the right of the gunner and faces to
the rear; No. 5 places himself on the left of No, I and faces
12
SERVICE OF THE PIECE
15-16
to the rear. Nos. 3 and 4 place themselves with their backs
toward the caisson chest close up against the chest, No. 4
on the right and No. 3 on the left of the trail. Higher-
numbered cannoneers take post as directed by the chief of
section.
(2) The limbers are brought up as described in Part Two,
PM 6-5. As soon as the Umber has halted in prolongation
of the piece trail, the gunner and No. 1 spring to the trail
handles and raise the trail. Nos. 2 and 5 hasten to the
piece wheels and prepare to assist in any movement of the
carriage that may be necessary. The gunner and No. 1 place
the lunette over the pintle; the gunner then latches the pintle.
The caisson is limbered simultaneously in the same manner;
Nos, 3 and 4 handle the trail, No. 4 latching the pintle.
Higher-numbered cannoneers assist by working at the wheels
of the caisson in any movement of the carriage. As soon
as the carriages are limbered, cannoneers take their posts
at the carriages limbered (fig. 3) ,
b. To limber rear. — The carriages being in position and in
maTeh order (par. 20) , the command is; LIMBER REAR.
(1) No. 4 releases the caisson brake; Nos. 3 and 4 raise
and secure the caisson prop. All cannoneers working to-
gether run the caisson 15 yards straight to the rear of the
line of spades. Nos. 3 and 4 lower the caisson prop, No. 4
sets the caisson brake, and all the cannoneers take posts for
limbering (a (I) above) .
(2) The limbers are brought up and the limbering is
completed as prescribed in a (2) above.
Section VI
UNCOUPLING AND COUPLING
■ 16. Uncoupling. — a. General, — At drills, trucks are posted
as directed by the battery commander. In active service and
in instruction simulating it, the trucks are conducted by
the first sergeant to a place previously designated by the
battery commander, where they are disposed so as to take
the best advantage of cover and concealment. If no cover
and concealment are available, they are located in rear of
177139'— 39 3
13
16-17
SERVICE OF THE PIECE
either flank, faced to the front, with wide Intervals between
them.
o. To fire to the front.— The command is: ACTION
FRONT. If marching, the trucks halt at the command or
signal. The cannoneers, if mounted, dismount after the
trucks have halted.
(1) The piece. — The gunner and No. 1 hasten to the -wheels
nearest their respective posts, Nos. 2 and 5 hasten to the
trail handles, No. 2 on the right. No. 2 unlatches the pintle
and assisted by No. 5 raises the trail from the pintle; Nos.
2 and 5, assisted by No. 1 at the wheel, swing the piece 180°
clockwise and lower the trail to the ground. Prior to the
turn, the gunner sets the brake on the pivot wheel (the wheel
adjacent to the gunner's post) , and when the turn is com-
pleted No, 1 sets the other brake. Nos. 3 and 4 unload the
ammunition, tools, and accessories from the truck and place
them to the left of the piece as directed by the chief of sec-
tion. When the trail has been lowered to the ground, the
gunner and Nos. 1, 2, and 5 assist Nos. 3 and 4 in completing
the unloading. When the unloading has been completed, the
chief of section commands or signals drive on. The gunner
and all cannoneers take their posts (par. 19) .
(2) The trucks. — At the command drive on, the trucks
move out and are conducted by the first sergeant to their
previously designated position.
c. To fire to the rear. — The command is: ACTION REAR.
The movement is executed according to the principles of
action' front except that the piece is not turned after
uncoupling.
d. To fire to the flank. — The command is : ACTION RIGHT
(LEFT). The movement is executed according to the prin-
ciples of achon front, with the following modifications: After
uncoupling, the trail is turned 90° away from the direction of
fire, and the piece is run forward sufficiently to clear the track
made by the truck. Articles unloaded from the truck are
placed on the ground so as to clear the track made by the
truck,
■ 17. Coupling. — a. The pieces being in position and in
inarch order, the command is: COUPLE. The trucks under
14
SERVICE OF THE PIECE
17-18
the command of the first sergeant approach the position from
the right (left) flank. As each truck approaches its piece,
it turns to the left (right) and halts in prolongation of the
trail of the piece.
b. All cannoneers working together under the direction of
the chief of section load the tools, accessories, and unex-
pended ammunition. Then Nos. 2 and 5 hasten to the trail
handles. The gunner and No. . 1 release the brakes. The
truck upon signal from the chief of section is maneuvered
backward until the pintle is almost over the lunette. Nos. 2
and S raise the trail and place the lunette over the pintle.
No. 2 latches the pintle. All cannoneers take their posts
(par. 8).
Section VII
PREPARATION FOR ACTION AND MARCH ORDER
■ 18. To Prepare for Action. — a. The carriages being in po-
sition unlimbered (uncoupled), the command is: PREPARE
FOR ACTION. Duties of the individuals are as follows:
(1) Chief of section. — (a) Supervises the work of the
cannoneers.
(0) Inspects the materiel, verifies the fact that the recoil
mechanism contains the proper amount of oil (par. 47) ; and,
when the operations have been completed, reports to the
executive, "Sir, No. (so and so) in order," or reports any
defects which the section cannot remedy without delay.
(2) Gunner. — (a) Assisted by No. 1, dismounts the sight
chest and places it to the left of the piece.
(b> Assists No. 1 to unsnap the howitzer cover,
(c) Removes the left trail pin.
((J) Unstraps the front end of the aiming stake on the left
trail.
(c) Replaces the left trail pin after the left trail is spread.
(/) Removes the panoramic sight, the range Quadrant,, and
the elbow telescope from the sight chest; hands the range
quadrant and elbow telescope to No. 1; seats the panoramic
sight in its bracket.
(ff) Sets deflection zero and centers the bubbles.
(h) Takes his post.
15
18
SERVICE OF THE PIECE
(3) No. 1. — (a) Assists the gunner to dismount the sight
chest.
(b> Assisted by the gunner, unsnaps the howitzer cover and
places the breech section to the right of the piece.
(c) Removes the right trail pin.
(d) Unstraps the front end of the aiming stake on the
right trail.
(e) Elevates the piece on signal from No. 2,
(/) Releases the right wheel brake and when necessary
assists No. 4 to raise the right wheel,
(ff) Replaces the right trail pin after the right trail is
spread.
(h) Receives the range quadrant and the elbow telescope
from the gunner and seats it in its bracket; when ordered by
the chief of section, rotates the elbow telescope to the firing
position.
(t) Sets site 300, range 3,000, and centers the bubbles.
(j) Opens the breech; examines the breechblock, the cham-
ber, and the bore, cleaning any parts requiring it; leaves the
breech open.
(Jc) Takes his post.
(4) No. 2. — (a) Passes around the left of the piece, removes
the muzzle section of the howitzer cover and tosses it to the
right of the piece.
(b) Removes the muzzle cover and tosses it to the right of
the piece.
(e) Releases the cradle lock, calls to No. 1 to elevate the
piece, and lowers the firing base to the firing position. (For
pieces equipped with a separate traveling lock, No. 2 first
releases and lowers the firing base; he then unlatches the
cradle lock, calls to No. 1 to elevate the piece, and lowers the
traveling lock.)
(d) Replaces the cradle lock,
(e) Releases the left wheel brake and when necessary
assists No. 3 to raise the left wheel.
(/) Takes his post.
(5) No. 3. — (a) Secures the left trail handspike and places
it in the left wheel socket ; unlatches left wheel.
(b) Assisted when necessary by No. 2, raises the left wheel,
latches the left wheel latch, and sets the wheel brake.
16
SERVICE OF THE PIECE
18
(e) Places the left trail handspike in the left trail socket
and spreads the left trail.
(.d) Places the fuze setter in position, and sets corrector
30, range 3,000.
(e) Puts a round of shrapnel in the fuze setter.
{/) Assisted by Nos. 4 and 5, arranges ammunition and
tools in an orderly and convenient manner.
(gr) Takes his post.
(6) No. 4. — (a) Secures the right trail handspike and
places it in the right wheel socket; unlatches the right wheel.
(b) Assisted when necessary by No. 1, raises the right
wheel, latches the right wheel latch, and sets the wheel
brake.
(c> Places the right trail handspike in the right trail
socket and spreads the right trail,
(<f) Assists No. 3 to arrange ammunition and tools in an.
orderly and convenient manner.
(e) Takes his post.
(7) No. 5. — (a) As soon as the sight chest has been dis-
mounted, unlocks the trails and spreads them parallel.
(b) Folds the howitzeT cover and places it 1 yard to the
right of the right piece wheel.
(c) Places the muzzle cover on the howitzer cover.
(d) Removes the sponge-and-rammer staff from the travel-
ing position, assembles it, and places it on the howitzer cover.
(e) Removes the aiming stakes from the trails, assembles
them, and places them beside the sponge-and-rammer staff,,
or sets them out when so directed by the chief of section.
(/) Obtains the lanyard and attaches it to the trigger,
(tf) Assists No. 3 to arrange ammunition,
(ft) Takes his post.
b. The limbered (coupled) carriages may be partially pre-
pared for action before reaching the firing position. The
duties of the cannoneers are the same as when the carriages
are unlimbered (uncoupled) , but only such operations as are
practicable are carried out before the carriages are unlim-
bered (uncoupled) . Immediately after establishing the car-
riages in position, preparation for action is completed without
command, and the cannoneers take their posts for firing the
piece.
17
18-19
SERVICE OF THE PIECE
c. If prepare for action has not been orderei
carriages are established in the firing position, tl
habitually is given by the chief of section as soor
riages have been unlimbered (uncoupled). In
not desired, the caution "Do not prepare for a
be given.
fl 19. Posts of the Cannoneers, Carriages Unlh
coupled). — a. The carriages having been unlir
eoupled), posts are taken as follows:
(1) Chief of section. — The chief of section go
can control the service of the piece, hear coir
perform his duties effectively. A convenient poi
from the end of the trail on the side opposite tl
n
Ftgube 5. — Posts ol the cannoneers, carriages un
(2) Gunner. — On the left of the breech, c.
abreast of it, outside the trail.
(3) JVo. 1. — On the right of the breech, a
abreast of it, outside the trail.
(4) No. 2. — Two feet in rear of the gunner, ci
(5) No. 3, horse units. — Two feet in rear of
chest, on the right of the caisson trail.
(6) No. 3, truck-drawn units. — Two feet to th<
opposite the rear of the left piece wheel.
(7) No. 4. — Two feet in rear of No. 3, covering :
(8) JVo. 5. — Two feet in rear of No, 1, covering ;
18
SERVICE OF THE PIECE
19-30
b. At drill all stand at attention at their posts, facing the
front (fig. 5) . In firing and in combat, minor modifications
of these posts are required for the more efficient performance
of the duties in the service of the piece and to secure the
protection afforded by the materiel. Higher-numbered can-
noneers, if present, take posts as prescribed by the chief of
section.
c. In order to exercise the cannoneers in all the duties con-
nected with the service of the piece and to lend variety to the
drill, the posts of individual cannoneers should be changed
frequently.
■ 20. March Order. — a. Duties of individuals. — The carriages
being unlimbered (uncoupled) and prepared for action, to
resume the order for marching, the command is: MARCH
ORDER. Duties are as follows:
<1) Chief of section. — (a) Supervises the work of the
cannoneers.
(£>) Inspects the materiel; makes sure that the piece is not
left loaded; and, when the operations have been completed,
reports to the executive, "Sir, No. (so and so) in order," or
reports any defects which the section cannot remedy without
delay.
(2) Gunner, — (a) Removes the left trail pin.
(b) Traverses the piece to the center.
(c) Closes the covers on the levels and sets the tilting head
and deflection at zero ; removes the sight from its bracket,
id) Receives the range quadrant and elbow telescope from
No. 1 and returns it and the panoramic sight to the sight chest,
(e) Traverses the piece as called for by No. 2,
(/) Replaces the left trail pin.
(gr) Straps the front end of the aiming stake on the left
trail.
(ft) Assisted by Nos. 1 and 2, replaces the howitzer cover,
(i) Assisted by No. 1, mounts the sight chest.
(3) No, 1. — (a) Removes the right trail pin.
(b) Closes the breech.
(c) Hands the muzzle cover to No. 2.
19
20
SERVICE OF THE PIECE
(d) Closes the covers on the level; sets site 300, range 3,000;
removes the range quadrant and elbow telescope from its
socket and hands it to the gunner.
(e) When necessary, assists No. 4 to rotate the right wheel
to the traveling position.
(/) Elevates or depresses the piece as called for by No. 2.
(0) Replaces the. right trail pin.
(h> Straps the front end of the aiming stake on the right
trail.
(1) Assists the gunner to mount the sight chest.
(?) Assists the gunner and No. 2 to replace the howitzer
cover.
<fc) Takes his post.
(4) No. 2. — (a) Passes around the left of the piece, re-
ceives the muzzle cover from No. 1, and places it on the
muzzle.
(b) When necessary, assists No. 3 to rotate the left wheel
to the traveling position.
(c) Releases the firing base lock, brings the firing base up,
calls to the gunner to traverse and No. 1 to elevate or depress
as necessary, and locks the cradle lock. (For pieces equipped
with a separate traveling lock, No. 2 raises the traveling
lock, calls to the gunner to traverse and No. 1 to elevate or
depress as necessary, and locks the cradle lock; he then re-
leases the firing base lock and secures it in the traveling
position.)
(d) Assists the gunner and No. 1 to replace the howitzer
cover.
(e> Takes his post.
(5) No. 3. — (a) Closes the left trail to the parallel position,
(b) Removes the left trail handspike and places it in the
left wheel socket, releases the left wheel brake, and unlatches
the wheel,
(e) Assisted when necessary by No. 2, rotates the left wheel
to the traveling position and latches the wheel latch; sets the
left wheel brake.
((£) Places the left trail handspike in the traveling position.
(e) Sees that all fuzes are set at safe or Quick.
(/) Sets the fuze setter at corrector 30, range 3,000.
20
SERVICE OF THE PIECE
20
(ff) Replaces the fuze setter and tools in the section chest,
(ft) Assisted by Nos. 4 and 5, loads ammunition into the
caisson or prepaies it for loading into the truck,
(t) Takes his post.
(6) No. 4. — (a) Closes the right trail to the parallel posi-
tion.
ib) Removes the right trail handspike and places it <n the
light wheel socket, releases the right wheel brake, and un-
latches the wheel.
(e) Assisted when necessary by No. 1, rotates the right
wheel to the traveling position and latches the wheel latch;
sets the right wheel brake.
(d) Places the right trail handspike in the traveling posi-
tion.
(e) Assists No. 3 to load ammunition into the caisson or to
prepare it for loading into the truck,
(/) Takes his post.
(7) No. 5. — (a) Removes the lanyard and returns it to the
section chest.
(b) Secures the aiming stakes, disassembles them, places
them in the traveling position, and fastens the rear straps.
(c) Disassembles the sponge-and-rammer staff and fas-
tens it in the traveling position.
(tZ) Locks the trails in the traveling position,
(e) Assists No. 3 to load ammunition into the caisson or
to prepare it for loading into the truck.
(/) Takes his post.
b. To resume fire in another position. — (1) If it is intended
to resume firing shortly, but in another position, so that the
limbering (coupling) of the pieces is necessitated, the com-
mand march order is not given. In this case, at the com-
mand for limbering (coupling) , only such of the operations
incident to march order are performed as are necessary for
the movement of the piece and caisson and for the care and
security of the equipment.
(2) If the command march order is given while the pieces
are limbered (coupled), the operations pertaining to march
order are completed as described above.
177130° — 39 1
21
21-22
SERVICE OF THE PIECE
Section VIII
DUTIES IN FIRING
B 21. General. — a. In general, the duties in firing are as
follows:
(1) The chief of section is responsible that all duties are
properly performed, all commands executed, and all safety
precautions observed.
„ (2) The gunner sets the announced deflection, lays for
direction, and refers the piece.
(3) No. 1 sets the announced site and range (elevation)
and lays for elevation.
(1) No. 2 loads the piece and works with No. 5 in shifting
the trails.
(5) No. 3 operates the fuze setter or sets fuzes as ordered;
he passes projectiles to No. 2 when firing shell.
(6> No, 4 prepares ammunition; in time fire, he keeps
rounds in the fuze setter, sets the fuze, and passes rounds to
No. 2 for loading.
(7) No. 5 opens and closes the breech, fires the piece, and
works with No. 2 in shifting the trails.
f>. The duties of the gunner and Nos. 1, 2, and 5 are
mutually dependent. The same is true of Nos. 3 and 4.
c. When firing by individual sections at moving targets with
direct laying, the elbow telescope ordinarily is used, and the
duties of certain members of the howitzer squad differ slightly
from those given in this section. For duties in this type of
fire, see paragraph 30.
22. Chief of Section. — a. Enumeration of duties, — (1)
Assisted by No. 1, to lay for elevation when the gunner's
quadrant is used.
(2) To measure the elevation.
(3) (a) To measure the minimum quadrant elevation,
(b) To measure the minimum range.
(4) To indicate to the gunner the aiming point, the refer-
ring point, or the target.
(5) To follow Are commands,
(6) To indicate when the piece is ready to fire,
(7) To give the command to fire.
22
SERVICE OF THE PIECE
22
(8) To report errors and other unusual incidents of fire
to the executive.
(9) To conduct prearranged Are schedules.
(10) To record basic data.
(11) To observe and check frequently the functioning of
the materiel.
(12) To assign duties when firing with reduced personnel.
b. Detailed description of certain duties. — (1) To lay for
elevation when the gunner's quadrant is used. — (a) The chief
of section is first taught to read settings on the gunner's
quadrant and then to set the elevations announced. To set
an elevation on the gunner's quadrant, for example 361.8
mils, the chief of section sets the upper edge of the head of
index arm opposite the 360 mark of the graduated arc on
the quadrant frame and slides the slide level along the index
arm until its index is opposite the 1.8 mark of the scale on
the index arm. Care must be taken in setting the slide to
use the scale on the index arm which is on the same side of
the quadrant as the graduated arc on the frame which was
used in setting the index arm at 360 mils. After the slide
has been set at the proper index, the- clamp is tightened just
sufficiently to hold the slide in place.
(0) The command quadrant (so much) indicates that the
gunner's quadrant is to be used.
(c) The announced elevation having been set on the gun-
ner's quadrant, the piece loaded, and the breechblock closed,
the chief of section places the quadrant on the quadrant
seat with the words "line of fire" at the bottom and the arrow
pointing toward the muzzle. The chief of section must be
sure to use the arrow which appears on the same side of the
quadrant as the scale which he is using. He stands squarely
opposite the side of the quadrant and holds it firmly on the
quadrant seat, parallel to the axis of the bore. It is im-
portant that he take the same position and hold the quadrant
in the same manner for each subsequent setting, so that the
quadrant bubble will in each case be viewed from the same
angle.
(d) The chief of section then causes No. 1 to elevate or
depress the piece until the bubble is centered, being careful
23
22 SERVICE OF THE PIECE
that the last motion of the bubble is from front to rear. The
chief of section warns No. 1 when the bubble is approaching
the center, in order that the final centering may be performed
accurately.
(2) To measure the elevation, — At the command measure
the elevation, the piece having been laid, the chief of section
sets the slide level of the index arm of the gunner's quadrant
at zero and places the quadrant on the quadrant seat as in
laying for elevation ((1) above). He then moves the index
arm until the bubble passes to the end of the vial away from
the hinge of the index arm. He then slowly lowers the index
arm until the bubble just passes to the end of the vial toward
the hinge. He then allows the index arm to engage the arc
and slides the level along the index arm until the bubble is
accurately centered. He then removes the quadrant and
reads and announces the elevation thus set; for example,
"Elevation, No. (so and so), (so much)."
(3) To measure the minimum elevation or minimum range.
(a) 1. Minimum elevation with the gunner's quadrant. —
The command is: MEASURE THE MINIMUM
ELEVATION. The chief of section, sighting along
the lowest element of the bore, causes No. 1 to
operate the elevating mechanism until the line of
sight just clears the CTest. He then measures the
quadrant elevation as described in (2) above and
reports the angle read from the gunner's quadrant
to the executive, thus, "Minimum elevation, No.
(so and so), (so much)."
2. Minimum elevation with the elevation scale. — The
command is : MEASURE THE MINIMUM ELEVA-
TION, SITE (SO MUCH). The chief of section
causes No. 1 to set the announced site and to lay
as described above. No . 1 then centers the elevation
bubble with the range-and-elevation-scale knob
and reads the elevation. The chief of section then
reports the minimum elevation, to the executive,
thus, "Minimum elevation, No. (so and so), (so
much), site (so much)."
24
SERVICE OF THE PIECE
22
3. Minimum range. — The command is: MEASURE
THE MINIMUM RANGE, SITE (SO MUCH).
The chief of section causes the piece to be laid and
the elevation bubble to be centered with the range -
and-elevation-scale knob as described above.
No. 1 then reads the range setting, and the chief
of section reports this range as the minimum
range to the executive, thus, "Minimum range,
No, (so and so), (so much), site (so much) ."
(ft) When the executive announces the corrected minimum
elevation, or the corrected minimum elevation (or range)
and site, the chief of section records it in a notebook and
causes the gunner to chalk it on a convenient place on the
carriage.
(4) To indicate to the gunner the aiming point, the refer-
ring point, or the target. — Whenever an aiming c point, a refer-
ring point, or a target has been designated by the executive,
the chief of section will make sure that he has properly
identified the point in question. He will then indicate it to
the gunner. If there is any possibility of misunderstanding,
the chief of section will turn the sight until the horizontal and
vertical hairs are on the point designated.
(5) To follow fire commands. — The chief of section will
follow the fire commands mentally. He will not repeat the
commands, but will be prepared to give any element of the
last command to any cannoneer who has failed to hear it.
(6) To indicate when the piece is ready to fire. — When arm
signals between the chief of section and the executive can be
observed, the chief of section will extend his right arm ver-
tically as soon as the gunner has called "Ready," as a signal
to indicate that the piece is ready to fire. When arm signals
cannot be observed, the chief of section reports orally to the
executive, "No. (so and so) , ready."
(7) To give the command to fire. — When No. 5 can see
arm signals made by the chief of section, the chief of section
will give the command to fire by dropping his right arm
sharply to his side. When arm signals cannot be used, the
command no. (so and so) fire will be given orally. The chief
25
22
SERVICE OF THE PIECE
of section will not give the signal or command to fire until all
the cannoneers are in safe vositians.
(8) To reyort errors and other unusual incidents of fire
to the executive. — If for any reason the piece cannot be fired,
the chief of section will report promptly to the executive that
fact and the reason therefor; for example, "No, (so and so)
out, misfire." Whenever it is discovered that the piece has
been fired with an error in laying, the chief of section will
report that fact at once; for example, "No. (so and so) fired
with incorrect deflection." Whenever the gunner reports that
the aiming stakes are out of alinement with the sight, the
chief of section will report that fact and request instruc-
tions (par. 33). Likewise, other unusual incidents that affect
the service of the piece are promptly reported by the chief of
section,
(9) To conduct prearranged fire schedules. — Whenever the
execution of prearranged fires is ordered, the chief of section
will conduct the Are of his section in strict conformity to the
schedules prescribed.
(10) To record basic data. — Data of a semipermanent na-
ture will be recorded in a notebook by the chief of section.
This includes such data as minimum elevation, base deflec-
tions, including aiming points used; prearranged fires when
prepared schedules are not furnished; safety limits in eleva-
tion and deflection; number of rounds fired, with the date and
hour; and calibration corrections when appropriate.
(11) To observe and check the functioning of the ma-
teriel. — The functioning of all parts of the materiel will be
observed closely during firing. Before the piece is fired, the
chief of section verifies the fact that the recoil mechanism
contains the proper amount of oil and thereafter carefully
observes the functioning of the recoil system. Any evidence
of trouble (par. 47) is reported promptly to the executive.
(12) To assign duties when firing with reduced personnel. — .
Whenever the personnel of the section serving the piece is
temporarily reduced in numbers below that indicated in this
manual, the chief of section will make such redistribution of
duties as will best facilitate the service of the piece.
26
SERVICE OF THE PIECE
S3
H 23. Gunner. — a. Enumeration of duties. — (1) (a) To center
the bubbles on the sight mount.
(b) To set or change the deflection.
(c) To apply the deflection difference.
(cZ) To lay for direction.
(e) To call "Ready."
(/) To refer the piece.
(g) To record base deflection.
(h) To measure a deflection.
(2) For indirect laying or direct laying, the gunner per-
forms duties prescribed in (1) (a), (b), (e), (c£), and (e)
above.
(3) When directed, the gunner performs the duties pre-
scribed in (1) (/>, (.</), and (h) above.
b. Detailed description of certain duties. — (1) To set or
change the deflection. — (a) To set the deflection. — The gun-
ner is first taught to read deflections set on the sight and then
to set the deflections announced. At the command, far
example, deflection i,885, the gunner pushes the throw-out
lever with his right hand and with his left hand turns the
rotating head until the hundreds' graduation (18 in this case)
is opposite the azimuth- circle index. He then releases the
throw-out lever and grasping the azimuth-worm knob with
his left hand with the thumb on top turns the azimuth-
worm knob toward himself until the micrometer index is
opposite the graduation 85 of the azimuth micrometer. The
line of sight will then make a horizontal angle of 1,885 mils
with the axis of the bore.
(b) To change the deflection. — The gunner should be
trained always to grasp the azimuth-worm knob with his
left thumb on top, as the command for changing the deflec-
tion then will indicate the direction in which he should move
his thumb in turning the azimuth-worm knob. He also
should be taught that turning the azimuth-worm knob toward
the muzzle (away from him) decreases the deflection set on
the sight and results in moving the muzzle to the right when
the piece is laid with the new deflection. Similarly, turning
the azimuth- worm knob toward the breech (toward him-
27
23
SERVICE OF THE PIECE
self) increases the deflection and results in moving the
muzzle to the left when the piece is laid. The deflection
having been set at 1,885 mils, if a subsequent command be,
for example, right 65, the gunner turns the azimuth-worm
knob by moving his thumb away from himself until the
micrometer index has moved 65 mils on the graduations of
the azimuth micrometer. Since turning- the azimuth-worm
knob away from himself decreases the deflection, the result-
ing deflection will be 1,820 mils. Should the command be
left (so much) , the deflection setting is changed in a similar
manner, except that the gunner moves his thumb toward
himself.
(2) To apply the Reflection difference. — (a) The com-
mand is: ON NO. (SO AND SO) OPEN (CLOSE) (SO
MUCH) . The gunner of the piece indicated in the command
does not change the deflection set on his sight. Each of the
other gunners changes his sight setting by the number of
mils specified in the command if his piece is next in line to
the piece indicated; by twice this number of mils if his piece
is second in line from the piece indicated; by three times this
number of mils if his piece is third in line from the piece
indicated.
(6) If the command is, for example, on no. i open s, the
gunner on No. 1 makes no change; the gunner on No. 2 turns
the azimuth- worm knob by moving his thumb toward him-
self and sets off 5 mils once; the gunner on No. 3 turns the
azimuth-worm knob in a similar manner, except that he
sets off 5 mils twice, a total of 10 mils; the gunner on No. 4
turns his azimuth-worm knob in a similar manner, except
that he sets off 5 mils three times, a total of 15 mils.
(c) Should the command be, for example, oM ho. 3 close
io, the gunner on No. 1 turns the azimuth-worm knob by
moving his thumb toward himself and sets off 10 mils twice,
or a total of 20 mils; the gunner on No. 2 turns his azimuth-
worm knob in a similar manner, except that he sets off 10
mils once; the gunner on No. 3 makes no change; the gunner
on No. 4 turns his azimuth-worm knob by moving his thumb
away from himself and sets off 10 mils once.
(<I) In turning the azimuth-worm knob the gunner must
remember that the movement of the muzzle will follow the
28
SERVICE OF THE PIECE
83
movement of his thumb. For example, grasping the azimuth-
worm knob with his left thumb on top, to move the muzzle
to the right, his thumb moves toward the muzzle, and he can
be taught to visualize the movement as pushing the muzzle
away from him (to the right) ; to move the muzzle to the
left, his thumb moves toward the breech, and he can be
taught to visualize this movement as pulling the muzzle to-
ward him (to the left) .
(e) In training gunners to apply the deflection difference, it
will be found advantageous to teach them to use the sight
as a mechanical adding machine. For example, if the com-
mand is on no. 1 open 8, the gunner on No. 4 first sets off 8
mils, then after an imperceptible pause another 8 mils, and
so on until he has set off 8 mils three times. This method
requires no mental arithmetic.
(/) When a deflection change and a deflection difference
are announced at the same time, for example: right 30, on
no. i close 5, both of which affect the gunner's piece, he will
first set off the deflection change and then apply the deflection
difference.
(3) To lay for direction. — (a) Direct laying on a stationary
target. — The deflection having been set, the gunner traverses
the piece by turning the traversing handwheel until the ver-
tical hair of the sight is on his part of the target. If the
amount of movement necessary to lay on the target is greater
than can be obtained by traversing, the trails must be shifted.
To shift the trails, the gunner commands or signals muzzle
right (left). Nos. 2 and 5 working at the left and right
trail handspikes, respectively, shift the trails so that the
muzzle moves in the indicated direction, until commanded to
stop by the gunner. The gunner then completes the laying
by bringing the vertical hair of the sight on the target.
(t>) Indirect laying. — The deflection having been set, the
gunner brings the vertical hair of the sight on the aiming
point by traversing the piece. If the amount of movement
is greater than can be obtained by traversing, the trails are
shifted as explained in (a) above.
(c) Procedure to insure accuracy. — To take up lost motion,
the final movement of the traversing handwheel should be
such as to cause the vertical hair of the sight to approach the
29
33-24
SERVICE OF THE PIECE
aiming point from the left. The gunner should habitually lay
with the vertical hair of the sight on exactly the same portion
of the aiming point or target for each round.
(4) To call "Ready." — The piece having been laid for direc-
tion, the bubbles centered, and No. 1 having called "Set," the
gunner verifies the laying, moves his head clear of the sight,
and calls "Ready" to indicate that his piece is ready to be fired.
(5) To refer the piece. — The piece having been laid for
direction, to refer the piece, the command is: 1. aiming point
(so and so), 2. REFER. Without disturbing the laying of the
piece, the gunner brings the vertical hair of the sight on the
new aiming point (referring point). He then reads and an-
nounces the deflection thus set and records the deflection and
the referring point on a convenient part of the carriage. Two
referring points usually are used, one for day and another for
night. A referring point should be at least 50 yards from the
sight, preferably to the rear. Frequently it will be necessary
to use the aiming stakes as referring points, particularly for
night use.
(6) To record base deflection. — At the command record
base deflection, the gunner records the deflection set on the
sight upon some convenient part of the carriage or upon a
data board (par. 41).
(7) To measure a deflection. — The command is: 1, aiming
point (SO and so), 2. MEASURE THE DEFLECTION. The
piece having been established in direction, the gunner turns
the sight until the vertical hair is on the aiming point, He
then reads and announces the deflection,
H 24. No. 1. — a. Enumeration of duties. — (1> (a) To set the
angle of site.
(b) To set the range or elevation.
(c) To lay for range (elevation).
id) To call "Set."
(2) For indirect laying without the gunner's quadrant or
for direct laying (except when using the elbow telescope as
prescribed in par. 30), No. 1 performs the duties prescribed
in (1) (a), (b), (c), and (d) above.
(3) For indirect laying with the gunner's quadrant, No. 1
performs the duties prescribed in CI) (c) and (d).
30
SERVICE OF THE! PIECE
34-25
p. Detailed description of certain duties. — (1) To set the
angle of site. — No. 1 is first taught to read angle-of-site set-
tings, and then to set announced angles of site. To set an
angle of site, No. 1 turns the angle-of-site knob until the
number of hundreds announced is opposite the index of the
angle-of-site scale and the tens and units opposite the index
of the micrometer. In setting the angle of site, No. 1 must
look squarely at the micrometer index.
(2) To set the range or elevation. — (a) Range. — No. 1 is
first taught to read range settings on the graduated range
scale and then to set ranges. To set a range, No. 1 turns the
range drum until the pointer is opposite the announced range,
making sure that the last movement is in the direction of
increasing range.
(b) Elevation. — The elevation may be set on the elevation
scale. No. 1 is first taught to read elevations on the elevation
scale and then to set announced elevations. Elevation is. indi-
cated by a scale graduated in hundreds of mils from zero to
800 and a micrometer scale graduated from zero to 100. To
set an elevation, No. 1 turns the range drum until the an-
nounced elevation is set on the elevation and micrometer
scales, making sure that the last movement is in the direction
of increasing elevation.
(3) To lay for range (elevation). — The angle of site and
range (elevation) having been set, No. 1 turns the elevation
handwheel until the bubble of the angle-of-site level is cen-
tered, making sure that the last movement of the elevating
handwheel is in the direction of decreasing range (elevation) .
In centering the bubble, No. 1 must be careful to look squarely
at it.
(4) To eaU "Set." — When No. 1 has completed his duties in
laying the piece, and the breech has been closed, he calls
"Set."
!S 25. No, 2. — a. Enumeration of duties. — (1) To load the
piece.
(2) When necessary, to man the left trail.
(3) In volley fire, to call out the number of the round.
o. Detailed, description of certain duties. — (1) To load the
piece. No. 2 receives the round from No. 3 (in shrapnel fire
31
25-86
SERVICE OF THE PIECE
from No. 4) , grasping it with his right hand at the base of the
case and his left hand in rear of the ogive. He inserts the
round in the chamber, removes his left hand, pushes the round
into the chamber with his right hand, and when he feels the
round strike the extractor removes his right hand. At high
elevations it may be necessary for No. 2 to keep his closed fist
against the base of the cartridge case until the round is firmly
seated against the extractor and the closing motion of the
breechblock has been started. No. 2 will be particularly care-
ful to avoid striking the fuse against any portion of the
materiel. To prevent premature bursts caused by projectiles
being struck on the fuse by the piece in recoil, a round, to be
loaded will be held well out of the path of recoil of the
howitzer until the latter is again in battery. (AR 750-10.)
(2) When necessary, to man the left trail. — See paragraph
23b (3).
(3) 7*o call out the number of the round. — To insure that
the correct number of rounds is fired in volley fire, No. 2 calls
out the range and the number of the round as he loads the
piece ; and as he loads the last round adds "Last round." For
example, when two rounds are to be fired at 2,800, he calls
out, "2,800 one; 2,800 two, last round." He should not speak
louder than is necessary to insure his being heard by the
members of his own gun squad.
H 26. No. 3. — a. Enumeration of duties. — (1) To set the fuze
setter.
(2) To set fuzes when using the hand fuze setter or when
shell is being fired.
(3) To pass rounds to No. 2 when shell is being fired.
b. Detailed description of certain duties. — (1) To set the
fuze setter. — (a) The series of fire commands for initially
opening fire with time-fuzed projectiles will contain the data
to be set on the fuze setter. These commands are, for ex-
ample, corrector 28, 3,600. For subsequent rounds, the cor-
rector setting is increased (decreased) at the command up
(DOWN) (SO much) .
(&) No. 3 is first taught to read data set on the fuze setter
and then to set data announced. To set data on the bracket
fuze setter, No. 3 turns the corrector-worm knob with his
32
SERVICE OF THE PIECE
26
right hand until the movable index Is opposite the graduation
on the corrector scale, corresponding to the corrector an-
nounced. He then turns the range -worm crank until the
graduation on the range scale, corresponding to the range
announced, is opposite the fixed index,
(c) To set data on the hand fuze setter, No. 3 turns the
corrector-worm knob until the graduated line on the cor-
rector scale, corresponding to the corrector announced, Is in
coincidence with the index engraved on the rim of the case.
He then turns the knob on the range -scale worm until the
graduation on the range scale, corresponding to the range
announced, is in coincidence with the index on the index bar.
(d) If the range to be set on the fuze setter differs from
that to be set on the piece, the command fuze range (so
much) will be given. In this case No. 3 sets the fuze range
on the fuze setter, disregarding the range announced for the
piece.
(e) If the command percussion is given, the fuze setter is
not used. However, No. 3 keeps the range scale of the fuze
setter set according to the ranges announced. He is thus
ready to pass to time fire as soon as a corrector is announced.
(/) To insure accuracy in setting the scales of the fuze
setter, it is necessary that No. 3 look squarely at the scales
and their indexes. To take up lost motion, the final movement
of the scales should always be in a counterclockwise direction.
(fiO The fuze data having been set on the fuze setter, No. 3
calls "Cut" as a signal to No. 4 to set the fuze.
(2) To set fuses. — (a) Time fuzes. — No. 3 sets time fuzes
only when the hand fuze setter is used. The fuze data having
been set on the fuze setter as indicated above, to set the fuze,
the projectile being held by No. 4, No, 3 places the fuze setter
over the fuze. The fuze setter is then turned in the direction
indicated by the arrow on the fuze-setter case until the slot in
the range-ring carrier engages the pin on the graduated time-
train ring of the fuze. The guide plate and the range-ring
carrier will then bear firmly on the fuze. No. 3 continues to
turn the fuze setter in the direction indicated until the stop
pin attached to the corrector-scale support engages with the
fixed stop pin on the fuze and prevents further motion. When
33
36-27
SERVICE OF THE PIECE
the fuze has been properly set, the pointer which, is attached
to the top of the corrector scale will register with the grad-
uated line on the closing cap of the fuze.
(b) M-39 fuses. — No. 3 assisted by No, 4 removes adhesive
tape and shipping caps, and No. 3 inspects the setting of each
fuze, which should be quick. This is indicated by the head of
the striker extension being at the "in" position. To set the
fuze for delay, No. 3 grasps the upper end of the striker exten-
sion and places it in the "out" position by turning it in a
clockwise direction until further rotation is impossible. Turn-
ing the striker extension in a counterclockwise direction until
continuous clicking is heard sets the fuze at quick,
(c) M-48 fuzes. — No. 3 inspects the setting of each fuze,
which should be quick. This is indicated by the screw driver
slot in the fuze being turned toward SQ. To set the fuze for
delay, No. 3 turns the screw driver slot until it points toward
delay.
<3) To pass rounds to No. 2 in shell fire. — No. 3 after set-
ting the fuze passes the round to No. 2 in the most expeditious
manner, and in such a way that No. 2 is enabled to grasp the
base of the cartridge case with his right hand.
SI 27. No. 4. — a. Enumeration of duties. — (1) To arrange
ammunition and to clean and prepare it for firing.
(2) To set the fuze when the bracket fuze setter is used.
(3) To hold the round while No. 3 sets the fuze, when the
hand fuze setter is used.
(4) To pass the round to No. 2 in time fire.
(5) To prepare charges in shell fire.
b. Detailed description of certain duties. — (1) To arrange
ammunition and to clean and prepare it for firing, — No. 4,
when time permits, arranges the rounds so that they are
within easy reach. He inspects each projectile to- see that it
is free from sand and dirt and that the rotating band is not
burred. Any foreign matter will oo removed by wiping with
a piece of waste. Projectiles having burred rotating bands
should be placed aside temporarily until the burs can be
removed with a file.
(2) To set the fuze when the bracket fuse setter is used. —
When the command corrector <so much) is given, No. 4 pro-
34
SERVICE OF THE PIECE
27
cures a round of shrapnel, removes the waterproof cap of the
fuze, and inserts the point of the projectile in the bracket fuze
setter, taking care that the lug nearest the point of the fuze
engages in the groove in the fuze setter. When No. 3 has
called "Cut," No. 4 turns the projectile with a steady and
uniform motion in a clockwise direction until further move-
ment is stopped. In turning the projectile, No. 4 stands to
the rear of the fuze setter, facing to the right front. His left
hand, back down, grasps the round at or near the forward end
of the cartridge case. The palm of the right hand is placed
on the base of the cartridge case, the fingers grasping the
edge of the base. While turning the projectile, No, 4 tabes
care to hold it firmly against the guide and to beep the fuze
well engaged by a steady pressure on the base of the car-
tridge case with his right hand. No, 4 then removes the
round by lifting it directly out of the fuze setter, taking
care not to strike the lugs of the fuze against any part of the
fuze setter. The time of burning may be read from the^
graduated ring of the fuze. When directed by the chief of
section, No. 4 will read and announce the time of burning
after setting the fuze. A time fuze which has been set for
any desired time of burning can be reset to S (Safe) by
setting the fuze-setter range ring to S, the corrector to nor-
mal (30) , and resetting the fuze. The fuze should be in-
spected to see that the S on the graduated time ring of the
fuze is in line with the marks on the upper time- train ring
and on the body of the fuze. Fuzes set but not fired will be
reset to S (Safe), inspected, and returned to the chest or
other container by No. 4. If the command percussion is
given, No. 4, after removing the waterproof cap, passes the
round directly to No. 2 for loading.
(3) To hold the round while No. 3 sets the fuse, when the
hand fuze setter is used. — No. 4 holds the round while No. 3
sets the fuze. No. 4 procures the round, removes, the water-
proof cap, faces to the right, and partially kneels on the
right knee. He places the base of the cartridge case on his
right thigh just above the knee. He grasps the round with
both hands, the right arm resting on his right thigh, the
left arm braced against his left thigh. The round is held
35
37-28
SERVICE OF THE PIECE
firmly, pointing upward in the general direction of No, 3's
head, while No. 3 sets the fuze.
(4) To pass the round to No. 2 in time fire, — No. 4 passes
the round to No. 2 in the most expeditious manner and in
such a way that No. 2 is enabled to grasp the base of the car-
tridge case with his right hand.
(5) To prepare charges in shell fire. — The propelling charge
in the cartridge case consists of four sections, as follows : The
bottom one, charge I; the bottom two, charge n; the bottom
three, charge HI; and all four sections, charge IV. At the
command for the charge to be used, No. 4 removes the pro-
jectile from the cartridge case (except in case of charge IV) ,
and if the command, for example, is charge hi, removes the
top section, thus leaving three sections in the cartridge case.
He then replaces the cartridge case on the projectile and
passes the round to No. 3. Unused powder sections are placed
at a convenient and safe location, and at a convenient time
disposed of as the executive may direct.
■ 28. No. 5. — a. Enumeration of duties. — CI) To open and
close the breech.
(2) To fire the piece.
(3) When necessary, to man the right trail.
(4) To keep empty cartridge cases out of the way.
(5) To use the rammer.
b. Detailed description of certain duties. — (1) To open and
close the breech. — (a) To open the breech.— -No. 5 grasps the
operating handle with his right hand and compresses the
lever latch. He rotates the lever to the right, sliding the
breechblock to the right. As soon as the breech is open, No.
5 looks through the breech to see that it is clear.
(b) To close the breech. — No, 5 grasps the operating lever
with his right hand and rotates the lever to the left, sliding
the breechblock to the left.
' (c) Opening and closing the breech. — When No. 5 under-
stands the functioning of the breech mechanism, Nos. 5 and 2
are instructed in loading and unloading the piece. The
breech being open, No. 5 rests his right hand lightly on the
operating lever ready to> close the breech. As the round is
36
SERVICE OF THE PIECE
38
inserted and pushed home by No, 2, No. 5 will start the closing
motion of the block as soon as he feels the jar of the round
striking the extractor. No. 5 must be careful not to grasp the
operating lever firmly as the round is pushed home, since to
do so may cause the extractor to strip the rim on the cartridge
case and cause a jam. The drill projectiles used for this in-
struction must be in good condition. To avoid damaging the
projectiles when they are ejected, a mat or similar cushion
should be placed at the point where they fall. If full-weight
drill projectiles are used, No. 2, standing at the breech, re-
ceives the ejected round with both hands.
(2) To fire piece. — At the chief of section's command no.
<so and so; fire, No. 5 with his left hand draws the lanyard
smartly to the rear so as to trip the trigger arm. If the chief
of section gives the command stand clear, No, 5 steps outside
the right wheel and fires the piece by leaning over so as to
reach the lanyard. The chief of section may caution "With
the long lanyard." In this case, No. 5 attaches the lanyard
guide pulley to the handle of one of the trails or to a state
driven at a convenient position between the trails, attaches
the loop of the lanyard to the trigger knob, steps clear, and
fires as previously described. No. 5 detaches the long lanyard
immediately after each round is fired. In case of a misfire,
the instructions contained in paragraph 39 will be followed.
(3) When necessary, to man the right trail. — See para-
graph 23b (3) .
(4) To keep empty cartridge eases out of the way. — No. 5
throws the empty cartridge eases well to the rear of the left
trail of the piece.
(5) To use the rammer. — The sponge and rammer will be
handled by Nc. 5 only. The rammer is used to extract un-
frred rounds or cartridge cases which cannot be ejected by the
extractor. To extract a cartridge case which cannot be
ejected by the extractor, the bottom of the inside of the case
is tapped lightly until it is loosened and can be pushed out of
the chamber. No. 2, standing at the breech, receives the
cartridge case in both hands. To extract an unfired round,
the procedure prescribed in paragraph 38 will be followed.
37
39-30
SERVICE OF THE PIECE
Section IX
ADDITIONAL INFORMATION ON THE SERVICE OP THE
PIECE
■ 29. Accuracy in Laying. — Sighting and laying instruments,
fuze setters, and elevating and traversing mechanisms will be
manipulated so as to minimize the effects of lost motion. This
requires that the last motions in setting instruments and in
laying be always in the directions prescribed, To insure accu-
rate laying, the gunner and any other cannoneers who have
duties in connection with laying the piece invariably will be
required to verify the laying after the breech has been closed.
When the piece must be established on uneven ground, it is
desirable for accurate firing that the three points of support
be leveled by pioneer work.
■ 30. To Fire by Individual Sections with Direct Laying at
Moving Targets. — a. The chief of section observes the target,
estimates its range and speed, and gives such directions and
commands to the cannoneers as will aid them in laying and
firing the piece,
b. The gunner lays for direction with the panoramic sight;
No. 1 lays for range with the elbow telescope, using the range
lines, (This automatically compensates for the site of ttie
target.) The piece is kept laid continuously by the gunner
and No. 1. No. 2 loads the piece and No. 5 operates the breech
and fires the piece, as rapidly as possible, without regard to
the operations of laying.
c. At the command of the chief of section right (left)
(so MircH), the gunner sets the deflection change ordered
(having previously set his deflection at zero) , and tracks the
target by traversing with the traversing handwheel. For the
first round, being on the target and No. 1 having called "Set,"
the gunner gives the command fire. Subsequent rounds are
fired "without further command.
d. No. 1 using the elevating handwheel keeps the elbow-
telescope range line for the announced range continuously on
the base of the target. For the first round only, No. 1 calls
"Set" when the appropriate range line is on the base of the
target.
38
SERVICE OF THE PIECE
30-32
e. Firing Is begun at the chief of section's command com-
mence firing and continues until the command cease firing
is given.
/. The chief of section observes the fire and gives such
changes in deflection and range as are indicated thereby.
These changes are applied on the scale of the panoramic sight
and in the reticule of the elbow telescope by the gunner and
No. 1, respectively, without stopping the fire. For maximum,
effectiveness, an available cannoneer should be used to set
changes in deflection, thus permitting the gunner to track the
target continuously.
■ 31. Fire at Will. — a. The piece being in position and pre-
pared for action, in case of sudden attack, when the target
appears at a range of less than 500 yards, the executive may
command: 1. target (so and soi, 2. FIRE AT WILL. The
chief of section repeats this command.
(1) The gunner keeps the piece laid directly on his portion
of the target throughout the firing. No, 1 keeps the 500-yard
line of the elbow telescope on the base of the target. No. 3
sets corrector 30, range zero. No. 4, If shrapnel is used, sets
fuzes continuously.
(2) Firing is commenced at the command of the chief of
section: NO. (SO AND SO) FIRE. The piece is loaded and
fired as rapidly as possible until the command cease piking,
or until the enemy disappears from view or actually reaches
the piece.
b. In fire at will, refinements of laying are not attempted,
rapidity of fire being of primary importance. Shrapnel, if
available, will be used. If shrapnel is not available, shell,
charge IV, set at delay will be used. In general, the pro-
cedure in firing shell is the same as with shrapnel except that
No. 1 lays well below the lowest visible element of the target.
■ 32, Aiming Stakes. — When a suitable natural aiming point
is not visible, the piece, after it has been laid initially for
direction, is referred to the aiming stakes as described in
paragraph 23b (5) . Two aiming stakes are used for each
piece. Each stake is equipped with a light for use in firing at
night. One stake is set up in a convenient location at least
100 yards from the piece. The other stake is set up at the
39
33-36
SERVICE OF THE PIECE
midpoint between the first stake and the piece, and is lined in
by the gunner so that the vertical hair of the sight and the two
aiming stakes are all in the same vertical plane. Any lateral
displacement of the piece during firing can then be detected
easily and corrected for as indicated in paragraph 33. For
night use, the lights should be adjusted so that the far one
will appear several feet higher than the near one. The two
lights thus will clearly establish a vertical line on which the
vertical hair of the sight can be laid.
B 33, Correction for Lateral Displacement. — When the gun-
ner notes that the piece is out of line with reference to the
aiming- stakes, he reports that fact to the chief of section.
The gunner continues to lay the piece, using the far stake,
until correction is authorized by the executive. The piece is
then moved back into its original position, or a correction
is made as follows : The gunner lays the piece by using the far
stake, then refers to the near stake, and finally lays on the
far stake with the new reading. The stakes are then realined
by moving the near stake. This correction is effective only
when the stakes have been equally spaced as indicated in
paragraph 32.
■ 34. Reporting Errors. — Each member of the howitzer
squad should be constantly impressed with the Importance
of reporting promptly to the chief of section any errors made
by members of the howitzer squad. The chief of section will
report errors immediately to the executive as prescribed in
paragraph 22b (8) .
■ 35. Cease Firing. — The command cease firing normally is
given, to the howitzer squad by the chief of section, but in
emergencies anyone present may give the command. At this
command, regardless of its source, firing will cease imme-
diately. If the piece is loaded, the chief of section will report
that fact to the executive. Firing is resumed at the an-
nouncement of the range or elevation.
■ 36. Suspend Firing,- — The command suspend firing is given
only when the battery is firing on a prearranged schedule and
a temporary halt in the firing is desired. At this command,
firing is stopped, but settings continue to be altered in con-
40
SERVICE OF THE PIECE
36-39
formity with the schedule. If the piece is loaded, the chief
of section will report that fact to the executive. Firing will
be resumed at the command resume firing.
■ 37. Changes in Data During Firing. — Except in Are at mov-
ing targets, the announcement to the gun squad of any new
element of firing data serves as a signal to stop all firing
previously ordered but not yet executed. If the piece is not
loaded at the announcement of a new element of firing data,
the new data will be set off and firing resumed at the an-
nouncement of the range or elevation. If the piece is loaded
with shrapnel, and the new data require a change in the fuze
setting, the piece will be unloaded (par. 38). If no change in
fuze setting is required or if the piece is loaded with shell, the
new data are set off, and the firing is resumed.
B 38. To Unload the Piece.. — a. When the command unload
is given, No, 1 brings the piece to the horizontal position, No.
5 opens the breech slowly, and No. 2, standing at the breech,
receives the ejected round with both hands in the case of
shrapnel and the cartridge case in the ease of shell. With
shell, and with shrapnel whenever the extractor fails to eject
the round, the rammer must be used.
b. No. 5 takes the sponge-and-rammer staff and inspects
the rammer head to see that it is thoroughly clean and that
the recess for the fuze is free from any foreign matter.
Under the direct supervision of an officer, he inserts the
rammer head in the bore and pushes it carefully in until it
encloses the fuze and comes in contact with the projectile.
He pushes the rammer head gently against the projectile and,
if necessary, taps the rammer staff lightly to dislodge the
projectile. He then pushes the projectile out of the breech
while No. 2, standing at the breech, receives the round in both
hands.
■ 39. Misfires. — In the event of a misfire, at least three at-
tempts to Are the primer will be made. The breechblock
will not be opened until at least 2 minutes have elapsed after
the last attempt to fire (AR. 750-10) . Rounds which have
misfired will be removed from the battery position and dis-
posed of as prescribed in TR 1370-A.
41
40-43
SERVICE OF THE PIECE
H 40. Ammunition. — Ammunition must be protected from
damage, especially to rotating bands and cartridge cases.
When it is received, it should be sorted into lots and placed
in the best available storage. Ammunition data cards should
be retained until after all ammunition pertaining thereto is
expended. Protection should be provided against moisture,
dirt, the direct rays of the sun, and, as far as practicable,
against hostile artillery fire and airplane bombs. Protection
against weather, dirt, and sun may be obtained by the use of
paulins below and above the ammunition, and suitable
dunnage below and between the layers. Protection against
hostile fire may be obtained by the use of small dispersed
stacks, trenches, or dugouts.
■ 41. The Section Data Board. — When positions are occu-
pied for more than a few hours, a data board may be used by
each section for recording such items as base deflection, cali-
bration corrections when appropriate, minimum range or
elevation, data for primary defensive fire missions, and other
data the need for which may be urgent,
■ 42. Firing from the Wheels. — In emergencies, the pieces
may be fired from the wheels, provided the sight chest is
first removed from the trails. In this case, the chief of sec-
tion must watch the degree of traverse and elevation closely
to be sure that the gun in recoil will not strike the trails. As
soon as practicable, the piece should be placed on the firing
base and the trails opened.
Section X
CARE AND MAINTENANCE OP MATERIEL
■ 43. General.— a. This section covers such operations in the
care and maintenance of the M3A1 howitzer as may be per-
formed by a battery in the field. With obvious modifications
it applies equally to the M2A1 and M3 carriages.
b. Complete instructions for battery maintenance, includ-
ing disassemblies, are found in the Technical Regulations and
Standard Nomenclature Lists referred to in paragraph 2,
especially TR 1305-75E and SNL C-26. Operations not
42
SERVICE OP THE PIECE
43-44
covered therein are the function of the Ordnance Depart-
ment.
c. In general, the battery is charged with preventive main-
tenance, that is, with routine cleaning, lubricating, and pre-
serving. Certain classes of repairs, adjustments, and replace-
ments of parts may also be made under the direction of an
officer or the chief mechanic. Parts which may be drawn by
a battery for replacement purposes are indicated in SNL C-26
by the symbol %. Unless specifically prohibited, such parts
may be installed by or under the direction of the battery
mechanic. For routine care and maintenance, specific duties
are assigned to individuals, squads, or sections, and a strict
accountability for the proper performance of such duties is
enforced.
d. In general, the following operations may be performed
within the battery:
(1) Draining and replenishing recoil liquid.
(2) Disassembly, maintenance, and assembly of breech and
firing mechanisms.
(3) Removal or replacement of the following assemblies:
(a) Top sleigh.
<b) Tube assembly.
(c) Breech ring.
(d) Bottom sleigh.
(4) Removal, adjustment, and replacement of the equi-
librators.
(6) Maintenance and adjustment of brake mechanism.
(6) Removal, care, and maintenance of wheels and wheel
bearings, including tires.
(7) Maintenance of wheel latch mechanism,
(8) Removal and replacement of gear-case covers for
cleaning gear cases.
(9) Minor operations necessary to replace certain parts
such as flexible joints, traversing and elevating stops, cradle
trunnion pins, firing-base locfc latch and lever, etc.
H 44. Cleaning. — a. Dirt and grit accumulated in traveling
or from the blast of the piece in firing settle on the bearing
surfaces, and in combination with the lubricant form a cut-
ting compound. Powder fouling attracts moisture and has-
43
44
SERVICE OP THE PIECE
tens the formation of rust. Dirt on nonbearing surfaces can
usually be removed by water; lubricated or other greasy parts
must be cleaned with dry-cleaning solvent applied with a rag.
The following cleaning materials are issued by the Ordnance
Department for use in the field:
(1) Soda ash (dehydrated sal soda). — Used for cleaning
the bore, breech mechanism, and firing mechanism after
firing.
(2) Dry-cleaning solvent. — For removing grease. It is pre-
ferred to kerosene because it does not leave a corrosive film,
and to gasoline because it is less inflammable.
(3) Crocus cloth. — This is the coarsest abrasive permitted
for cleaning rust and stains from bearing surfaces.
(4) Emery cloth. — Used for cleaning unfinished or non-
bearing steel surfaces only. Issued in five degrees of coarse-
ness, of which 00 is the finest.
(5) Burlap, jute. — Used for cleaning the bore.
(6) Cotton -waste, clean rags, and sponges. — For general
cleaning purposes.
b. A division of duties for members of the howitzer squad
in routine cleaning and maintenance is as follows:
(1) The gunner — the telescope, telescope mount, sight
bracket, and other sighting and laying equipment, including
the gunner's quadrant.
(2) Nos. 1 and 2 — the breech mechanism, the firing mech-
anism, the breech ring, and the tube assembly.
(3) No. 3— the fuze setter.
(4) Nos. 4 and 5 — the elevating and traversing mechanism,
and the recoil slides and grooves.
(5) Higher- numbered cannoneers assist in the operations as
directed by the chief of section.
c. Before firing, at lulls during firing, and immediately after
firing, the piece should be thoroughly cleaned and lubricated.
At other times it should be cleaned at intervals not exceeding
2 weeks, depending upon its use and its condition. The bore,
breech mechanism, and firing mechanism should be cleaned
as described in paragraph 48b. The top sleigh, tube as-
sembly, breech ring, and bottom sleigh should be removed,
cleaned, and lubricated. Particular emphasis should be placed
on the proper cleaning, dTying, and lubricating of the inter-
44
SERVICE OF THE PIECE
44-45
rupted threads of the tube assembly and of the breech ring,
the slides, and the unpainted bearing surfaces of each
assembly.
d. The exposed gears of the elevating and traversing mech-
anisms should be cleaned with dry-cleaning solvent, dried,
and coated with graphite lubricating grease. After the gears
are lubricated, the systems should be exercised to insure com-
plete and even distribution of the lubricant.
e. The moving parts of the equilibrators, firing base, firing-
base lock, cradle lock, and wheel latch mechanism should be
cleaned and lubricated in order to insure their positive and
ready action.
H 45. Lubrication. — a. To facilitate identification, all oil holes
and grease fittings should be made conspicuous by circling
with bright red enamel.
b. Light Umber, MS.— At least once every 6 months, the
wheel bearings should be cleaned, and the bearings and the
hub packed with fiber wheel-bearing grease. Every 2 weeks,
or more often if necessary, the following lubrication opera-
tions should be performed:
(1) The pressure lubricating gun filled with mineral lubri-
cating grease is used on the spring shackles (2 fittings) and
the limber-frame brackets (4 fittings) .
(2) The oiler filled with lubricating oil is used on the
doubletree bolt and the moving parts of the pintle.
(3) Oil is brushed on the edges of the spring leaves.
c. Light caisson, Ml. — At least once every 6 months the
wheel bearings should be cleaned, and the bearings and the
hub packed with fiber wheel -bearing grease. Every 2 weeks,
or more often if necessary, the following lubrication opera-
tions should be performed :
(1) The pressure lubricating gun filled with mineral lubri-
cating grease is used on the brake cam shaft, brake conduit,
brake shaft, caisson spring pins, caisson spring shaft, and
spring shackle pins (total of 12 fittings) .
<2) The oiler filled with lubricating oil is used on the ex-
terior moving parts of the brake mechanism, moving parts
of the pintle, and moving parts of the pole prop.
(3) Oil Is brushed on the edges of the spring leaves.
45
45
SERVICE OP THE PIECE
(With obvious modifications this chart applies also to the M2A1
and M3 carriages.)
TUBE ASSEMB LY ® □ Ha
CRADLE LOCK PIN tiTUENBUtKLFJ 4
RECOIL SLIDES it G&OOVE5 @ □ *
F-IRIWO BASE LOCK PLUNGER & PEDAL PIN ©□ A
1 FITTING -TRAVEHSINGGEABCASE ®+'* B *
FIRING BASE (TRAVELING 10Ck)WN0E PIN ©+ *
FLEXIBLE JOINT-TWERSms SHAFT ®+ *
LIFTING EYE PIN ©+ A
E<3UILIBBATOaT5uWNION,SOCKET tt. CYLINDER? ©+ A
MOVING PABXS-HANBBKAKE LEVER Q)+ A
1 FITTING -BRAKE CAM SHAFT
SUOINGSURFiCES-WNEEL LATCH @+ A
WHEEL BEAWN6S @»J2>
\ FITTING -WHEEL CARRIER BEARING <£+■»
1 FITTING-TRAIL HINGE PIN @+»
TSAIU LOCK PIN ©U3 *
1 HTTIV4G-ELEVATINGGEAR CASE ELAND © + »
TOP SLEIGH CLAMPING IATCH5XAM <|>+ A
MCWIW&PARTS-TElESCOpE MOUNT S^BMKET ©□ A
2PIWS-SIGHTING CHEST HINGE STPAP @+ A
Z PINS " STAFF SUPPORT © + A
1 FITTINGrTtfAVERSiNG HANOWHEEL SHAFT BRACKET ©+«
2 HOLES-TffiAVEKSlWG HANDWEELUANDLt @+ A
1 PIN-TRAIL LOCKLOOP ©+ A
1 FITT1W& C<IADU= TPAlNNtOHWH ®-V-<™
LUBRICANTS
® NEUTRAL OIL
© LUBRICATING OIL-USE LIGHT (SAE-20)WHEN
TEMPERATURE IS BELOW 50=F. OR HEAVY
6AE-50J WHEN ABOVE 50°F.
® MINERAL LUBRICATING GREASE
® FIBER WHEEL BEARING GREASE
© GRAPHITE LUBRICATING GREASE
46
HOW APPLIED
A OllETi
» PRESSURE LUBRICATING GUN
fi5. &RUSH OR CLOTH
<St»AHl> PACKING
Ficuhe 6. — Lubrication
SERVICE OF THE PIECE
45
A + ® PISTON ROO LATCH ALEVES
JEB + ® 1OP&B0TTOM SLEIGH -SLIDING SURFACES
A + © RECOIL INDICATOR
* B ® RECOIL SLIDES & G&OOvES
M + © TRAVERSING BACK
A H- © FIRING BASE CTfikVELING LOCKl HINGE PIN
™+® PINTLE PIN-1FITTIWG
+ © ELEVATING ARC
* + © EQUILIBRMOR TRUNNION, SOCKET E* CYLINDERS
A + <D HANDBRAKE LEVER -MOVING PARTS
»»+<
BRAKE CAM SHAFT - 1 FITTING
WHEEL LATCH - SLIDING SUKFACES
WHEEL BEARINGS
WHEEL CARRIER BEARING -1 FITTING
TRAIL HINGE PIKl-l FITTING
4 EI (D TRAIL LOCK PIN
•»+ ® ELEVATING GEAR CASE -I FITTING
A + © FLEXIBLE JOINT -ELEVATING SHAFT
AD® RANGE QUADWrJT&BRACKET-MOVING PASTS
»4- © ELEVATING HANOWHEEL SHAFT BRACKET- 1 FITTING
A + © ELEVATING HANOWHEEL HANDLE -Z HOLES
® CRADLE TRUNNION PIN -1 FITTING
A + ® TRAIL LOCK HOOK Et LEVER.- 2 PINS
M10 © BREECH RIN&
/mm ©OREECH U FIRING MECHANISMS
WHEN APPLIED
B DAILY DURING CONSTANT SERVICEjCfTHERWISE EVERY TWO WEEKS
+ EVERY TWO WEEKS
• EVERY SIX MONTHS
NOTE' AClAr firing or washinq, lubricate tuba assembly, breach and firing
mechanisms, slides, telescope mount and range quadrant brackets,
exposed qears, and unpainted boarinq or sliding surfaces. Immediately
before firing ana 1 durinq lulls, clecinandollaH bearing and sliding
surfaces of breech, firing andsighting mechanisms and cradle..
chart, 75-ram howitzer, M3A1.
47
45-47
SERVICE OF THE PIECE
d. Lubrication instructions for the howitzer and carriage,
M3A1, are covered in figure 6. While' being lubricated, parts
should be exercised to insure complete and positive distribu-
tion of the lubricant. Whenever time is available prior to
entering into action, all sliding and bearing surfaces which
come into play in the functioning of the howitzer and car-
riage should be cleaned and oiled to insure their free and
easy operation. Always after passing through water, the
wheel bearings should be cleaned and repacked with fresh
grease.
O 46. Protection Against Chemicals. — Whenever chemical
attacks are anticipated, all bright parts should be covered
with oil. After a gas attack, the oil is wiped off and fresh
oil applied. If mustard or other persistent gas is used, ab-
sorbent objects may be deeply contaminated, and even hard
surfaces may be dangerous for 6 to 8 days if the chemical is
not neutralized. Surfaces should be sprinkled with calcium
hypochlorite or chloride of lime, or painted with a whitewash
made from either. After 2 to 6 hours the lime is washed off
and the materiel rinsed thoroughly with water. When large
quantities are available, warm (but not boiling) water should
be used instead of calcium hypochlorite or chloride of lime.
In all cleaning operations, the gas mask and special gas-
proof gloves must be worn. All cleaning rags, sticks, etc.,
are disposed of by burying. They must not be burned as
the heat will disseminate dangerous vapor.
K 47. Recoil Mechanism. — a. General.— Battery maintenance
of the recoil mechanism is limited to exterior cleaning and
lubricating, and to draining and filling with recoil oil. Only
the heavy low-pour-point recoil oil as issued by the Ordnance
Department may be used in the recoil mechanism. It is espe-
cially important that this oil be kept free of dirt, water, and
air bubbles, and that it be not mixed with other oils. A full
reserve of oil for the recoil system amounts to approximately
one-half the contents of the screw filler. In using the screw
filler, eare must be exercised to prevent crossing of the threads.
48
SERVICE OF THE PIECE
47
The screw handle must be turned with both hands. The
amount of oil reserve in the system is shown by the position
of the oil index with reference to the extension on the oil-
index follower assembled in the recuperator cylinder head,
as follows:
(1) No reserve. — The indicator is at the bottom of the
recess. The howitzer must not be fired in this condition.
(2) Full reserve. — The end of the indicator is flush with
the extension on the oil-index follower.
(3) Excess reserve. — The oil index does not of itself show
when there is an excess of oil reserve, as the addition of excess
oil does not move the index out beyond the follower. The
piece must not be fired with an excess reserve.
b. Operations' prior to firing. — (1) The presence of a full
reserve of oil must be insured. When the index is flush with
the follower, to insure that there is not an excess reserve or
that the index is not stuck, oil should be drained off until the
index starts to move into its recess. Oil is then replenished,
the operation bsing stopped just as the index comes flush
with the end of the follower.
(2) The rear end of the recoil cylinder, the filling-and-
drain plug hole, and the oil-index recess should be examined
for oil leakage. The presence of a few drops of oil is not
important, but if there is undue leakage the piece must not
be fired, and the condition should be reported to the ordnance
maintenance company.
(3) The sleigh slides should be lubricated.
c. Operations during firing. — (1) During firing, the recoil
mechanism should be maintained at full reserve, and the
slides kept clean and properly lubricated.
(2) The chief of section constantly verifies the complete
return of the piece to battery. Periodically, he measures the
length of recoil by releasing the recoil indicator which wipes
off chalk or grease which has been placed on the cradle. For
the M3A1 carnage the maximum length of recoil is 31 inches
and the normal length is 29 inches.
49
47-48
SERVICE OF THE PIECE
(3) The chief of section constantly observes the behavior'
of the recoil mechanism in firing, and takes such action in
the case of malfunctioning as is indicated below:
Malfunction
Cause
Correction
Oil index projects
less than the required
distance.
(1) Loss of oil re-
serve.
(2) Loss of gas pres-
sure either through the
cylinder rear head or
past the floating pis-
ton.
(1) Drain the remainder of the
reserve oil and refill.
(2) Gus escaping by the floating
piston is indicated by an emulsi-
fied condition of the reserve oil
drained off. If in filling the
mechanism the oil index does not
inovo out and the oil screw filler
works easily, the gas pressure has
been lost. Substantiate this by
an attempt to drain the mechanism.
Oil will not spurt out unless some
pressure is present. Refer to ord^
nanco maintenance company for
repair.
Oil index remains
stationary when the
reserve is pumped in
against evident pres-
sure.
The packing is too
tight or the index is
broken or locked by
some foreign sub-
stance.
Drain off all reserve uil and refill.
While injecting the oil, tap the oil
index gently with each turn of the
screw filler. If the oil index fails
to move after employing the screw
filler, refer the matter to the
ordnance maintenance company.
However, the piece may be fired in
an emergency by draining oft the
reserve oil and. refilling with one-
half the capacity of The screw filler.
Howitzer returns to
battery with too great
a shock .
Excess reserve
caused b y ex.pansi.oiL
of oil as a result of
rapid firing.
Withdraw oil until the index is
ha Ifwav in TA r lijin flip rnw^hflnicTTi
has cooled off, refill to normal.
Howitzer fails to re-
turn to battery.
(1) Leakage of oil
past recoil piston.
(2) Insufficient re-
serve, dry or scored
bottom sleigh slide or
piston md, excessive
friction or loss of
nitrogen pressure.
(1) Remove cap screw in rear
head of recoil cylinder, elevate
piece and allow oil to escape
through relief opening.
(2) Establish a full reserve. If
the howitzer fails to return to
battery, examine the bottom
sleigh slides and piston rod. If
after lubricating or removing for-
eign matter the howitzer still fails
to return to battery, refer U> ord-
nance maintenance company.
H 48. Tube Assembly, Breech Mechanism, and Firing Mech-
anism. — a. Operations during firing. — CD During firing, all
exposed bearing surfaces must be kept clean and covered with
a^thin film of lubricating oil.
50
SERVICE OF THE PIECE
48
(2) Whenever the rate of firing permits, the bore should be
swabbed with clean water and a sponge.
(3) The chief of section should constantly observe for mal-
functioning of the materiel. The causes and corrections of
malfunctioning of the breech and firing mechanisms are given
in the following table:
Malfunction
Cause
Oorrcction
Fails fco fire, no per-
cussion on primer.
Broken firing spring;
broken or deformed, fir-
ing pin.
Disassemble firing lock and re'
plaf* broken or deformed part,
Fnils to fire until
primer is struck sev-
eral times.
(1) Firing inechajiisni
parts not working freely.
(2) Weak firing spring.
1 llflRQfif^mlil n fln'nir 1 r,r>lr anrl
LC AftAtjIILLJ 1c ill Lllg iOU-K. CSllU
examine for burs and rough spots.
If round, remove with crocus
cloth or an oilstone. Wash ports
with dry-cleaning solvent, dry
and lubricate before reassembly.
(2) If correction (1) above does
not remedy condition, replace fil-
ing spring.
Falls to fire when
proper percussion on
primer is obtained
(misfire).
Defective primer.
Make three attempts to iiro the
primer, then wait 2 ininntes be-
fore opening breech and replac-
ing round. (See par. 3D.)
Tails to eitraut
empty case.
Broken extractor.
Gently ram the case out. Ex-
amine the edge of the chamber for
burs. Remove burs, if any, with
crocus cloth or an oilstone. Ite-
place extractor.
b. Operations alter firing. — (1) As soon as possible after
firing, the breechblock, and firing mechanism should be dis-
assembled and all parts cleaned and lightly oiled. The bore
should be thoroughly cleaned while assembled to the carriage.
(Par. 44c.)
(2) The bore, breech mechanism, and firing mechanism are
washed with a solution of V 2 pound of soda ash or 1 pound
of sal soda in 1 gallon of water. Cleaning the bore is ac-
complished by means of a swab of burlap stitched around the
end of the rammer staff. No attempt should be made to
remove copper fouling. When all powder fouling has been
removed, the boTe should be swabbed with clear water and
then wiped dry. Finally, it should be lightly coated with
51
48-49
SERVICE OP THE PIECE
lubricating oil, either light or heavy, depending on thes j
weather. The cleaning may have to be repeated on succes-
sive days if there is evidence of sweating. If the piece is not
to be kept in constant service, the bore should be slushed with
rust-preventive compound instead of with oil.
■ 49. Wheels and Brakes. — a. General. — The care and main-
tenance of the wheel mechanism, including tires and brakes,
is a function of the battery. Tire pressure should be main-
tained at 30 pounds. Tires are removed at least once a '
year and the disk and rim cleaned and painted. Every 6
months, or oftener if necessary, the wheel hubs should be
removed, the old grease flushed out, new grease pressed into
the bearings and the hub by hand, and the wheel bearings
adjusted. The proper adjustment a<nd operation of the
brake system should frequently be cheeked.
b. Test of bearing adjustment. — At all halts during march-
ing the wheel hubs should be felt for overheating. During
the march the wheels should be observed to ascertain that
they are running true without side play. When the bearings
are adjusted, the adjustment should be checked by placing a
bar between the raised tire and the ground, at the same time
holding one finger on the cage of the outer bearing. When
in working the bar up and down a barely perceptible shake is
felt, and the wheel will rotate when given a slight spin, the
adjustment is correct.
c. Brake mechanism. — Brake adjustment is accomplished
by rotating the adjusting wedge. Prior to adjusting the
brake mechanism, wheel bearings should be checked for
proper adjustment and the brake mechanism lubricated. At
all times, lubrication of the brake cam and roliers must be
held at the correct amount to avoid saturating the brake
lining with grease. The procedure for adjustment is as
follows :
CI) Set the brake lever at the full released position.
(2) Jack up the wheel.
(3) Adjust the wedge until a drag is felt on the wheel.
Then back off just enough so the brake does not drag. Brakes
must be cold.
52
SERVICE OF THE PIECE
50
■ 50. Miscellaneous Parts of Carriage. — a. Equilibrators. —
(1) The outer surfaces of the lower cylinder must be kept
clean and lubricated with oil. proper lubrication of the trun-
nion pin at the top and the socket at the bottom must be
maintained. The battery is prohibited from performing any
operation other than the removal or adjustment of the
equilibrators.
(2) The following procedure should be observed in adjust-
ing an equilibrator:
(a) Place the howitzer at zero elevation.
(b) Insert the equilibrator assembling bolt through the
socket bearing of the bottom carriage and through the barrel
of the equilibrator. Advance the holt until it comes in con-
tact with the equilibrator spring guide tube plug, and screw
the bolt into the plug as far as it will go.
(c) Elevate the howitzer until the equilibrator trunnion
pin is clear of the bearing in the top carriage.
(d) Release the equilibrator trunnion pin lock and make
the desired adjustment by screwing the trunnion pin in for
lesser tension or out for greater tension.
(e) After the adjustment is completed reengage the lock,
lower the cradle to seat the equilibrator trunnion pin, and
remove the assembling bolt. (Caution. — Do not attempt to
remove the assembling bolt until the cradle is seated and the
spring tension is released.)
(3) An equilibrator is removed from the carriage by the
procedure outlined in (2) above, except that during operation
(2) (e) the howitzer is elevated to its maximum extent and
the equilibrator assembly removed.
b. Elevating and traversing mechanisms. — Every 6 months
the covers of the gear cases should be removed, the old grease
cleaned out, and the cases repacked with lubricant of the pre-
scribed type. Battery personnel are permitted to make the
disassembly necessary to clean the gear cases, to replace the
flexible joints, and to clean the shaft brackets. If the back-
lash in either handwheel exceeds one-quarter turn, the ord-
nance maintenance company should be requested to adjust
the system. Whenever the exposed gears are being cleaned
53
50-51
SERVICE OF THE PIECE
they should be examined for broken or deformed teeth and to
see that the arc or rack stops are in place and in good con-
dition.
■ 51. Sighting and Fire-Control Equipment. — a. General. —
Especial care is required to insure the positive and accurate
functioning of the sighting and nre-eontroi mechanisms.
Care must be exercised to prevent denting the soft metal sur-
faces or scratching the glasses. Dirt should be removed from
optical surfaces by brushing lightly with a camel's-hair brush.
Oil or grease should be removed from glass by applying alco-
hol, or if alcohol if not available by breathing on the glass and
then wiping lightly with lens paper or a clean soft cloth. The
unpainted steel surfaces should be kept covered with a light
film of high-grade lubricant to prevent corrosion. In general,
the sights are correct —
(1) In direction, if the deflection scales read zero when the
line of sighting is in a plane parallel to the vertical plane
passing through the axis of the bore.
(2> In elevation, if the algebraic sum of the range and site
settings indicates the same angle above the horizontal that is
measured with an accurate gunner's quadrant on the tube.
<3) If there is no excessive lost motion between the sights
and the tube.
b. Testing equipment. — Equipment used in testing sights
consists of bore sights and a gunner's quadrant. The target
for bore sighting may be a distant terrain object, more than
1,000 yards away, or a test target for use in close proximity.
In the latter case the displacement of the axis of sighting
from the axis of the bore must be correctly shown. For this
howitzer the panoramic telescope displacement is 14 inches
to the left and 6.42 inches above the axis of the bore. The
elbow telescope is 12.375 inches to the right and 6.42 inches
above the axis of the bore. An aiming stake with a wooden
block or marker attached retakes a suitable test target. In
direction tests it may be canted as the carriage is canted,
making leveling of the trunnions unnecessary. Tests can be
made without the bore sights by sighting through the firing
pin recess or a brass cartridge case with the primer removed,
using improvised cross hairs at the muzzle.
54
SERVICE OF THE PIECE
51
c. Test of the gunner's quadrant. — To test the gunner's
quadrant, set the scales at zero, place It on the quadrant seat
of the howitzer, and level the quadrant bubble by means of
the elevating handwheel. Then reverse the quadrant on its
seat. The bubble should center itself. If it does not it should
be adjusted at the earliest opportunity by the ordnance main-
tenance company. If it must be used, apply a correction in
the appropriate sense equal to one-half of the measured error
determined in the end-for-end test.
d. Telescope mount, M16 and panoramic telescope, Ml. —
Battery personnel are forbidden to disassemble any part of
the telescope or telescope mount, but are permitted to perform
certain adjustments. The following procedure may be used to
insure accuracy of the sighting and laying mechanism:
(1) Panoramic telescope and telescope mount assembly. —
(o) Level the carriage trunnions and tube with the gunner's
quadrant.
(i>) Bore -sight, placing the test target in alinement with
the bore, or note a distant terrain object which is in
alinement.
(c) Set all scales and micrometers at zero and center the
bubbles.
(d> Look through the telescope. If the intersection of the
cross hairs is on the appropriate part of the target the adjust-
ment is correct. If not, make tests and adjustment of
individual parts as explained in (2) to (5) below. Bach test
should be started with the tube and trunnions level and the
bubbles centered.
(2) Cross level of the telescope mount. — (a) Center the
cTOSs-level bubble and lay the vertical cross hair with zero
deflection on the appropriate part of the testing target or on
a distant terrain object.
(J>) Elevate the howitzer to its maximum and level the
longitudinal bubble. The cross-level bubble should be cen-
tered and the vertical cross hair should not have moved.
Ce) If the vertical hair has moved either to the right or
to the left, determine the error by turning the cross-leveling
knob by small trial movements until the vertical hair remains
on its target while the piece is elevated and depressed. Note
the position of the bubble. If it is not centered within one
55
51
SERVICE OF THE PIECE
division it should be repaired by the ordnance maintenance
company. However, it may be used by setting the bubble in
the position determined in the above test instead Of in its
true center,
(3) Longitudinal level of the telescope mount. — (cO With
1,600 i?i deflection, lay the vertical cross hair on a plumb bob
line and center the longitudinal bubble.
(&) By means of the elevation-micrometer knob of the
telescope move the vertical cross hair along the plumb bob
line. The vertical hair should not move either to the right or
to- the left.
.(e) If the vertical hair moves, determine the error by
moving the longitudinal-leveling knob by trial adjustments
until the vertical hair remains on the plumb bob line. Note
the position of the bubble. If it is not centered within three
divisions it should be repaired by the ordnance maintenance
company. However, it may be used by setting the bubble: in
the same relative position determined in the above test in-
stead of in its true center.
(4) Panoramic telescope for direction. — (a) If the vertical
cross hair of the telescope is to the left of the bore-sighted
target with zero settings, put it on by loosening the locking
nut on the sight bracket and adjusting the headless screw.
Tighten the locking nut and recheck.
Cb) If the vertical cross hair of the telescope with zero
settings is to the right of the bore-sighted target, put it on
by the deflection knob. Loosen the screw in the knob and
slip the micrometer around until the zero graduation registers
opposite the index, being careful not to disturb the cross
hair. Retighten the set screw and recheck.
(c) Periodically, check all sight brackets of the battery
with a single telescope and mount, and apply any necessary
correction of the vertical hair by loosening the locking nut
on the brackets and adjusting the headless screw. The tele-
scope for each weapon should then be adjusted as in (b)
above.
(5) Panoramic telescope for elevation. — If the horizontal
cross hair of the telescope with zero settings and bubbles
leveled is not on the bore-sighted target, put it on by turning
the elevation knob of the telescope. Then loosen the three
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SERVICE OF THE PIECE
51
jset screws on the knob and slip the knob around until the
zero graduation registers opposite the index, being careful
not to disturb the cross hair. Retighten the set screws and
recheck.
e. Range Quadrant, M3, and elbow telescope, M5. — As with
the telescope and mount, battery personnel are only permitted
to perform certain tests and adjustments with the range
Quadrant and elbow telescope. The following procedure may
be used to insure accuracy in this testing and adjusting:
(1) Range Quadrant, general. — (a) Lay the tube horizontal
and level the trunnions using the gunner's quadrant.
(b) If the angle-of-site bubble is centered when the angle-
of-site scales are set at 300 and the range and elevation scales
are set at zero, the range quadrant is in adjustment. If not,
adjust as indicated In (2) to (4) below.
(2) Cross level of range quadrant. — (a) Install the elbow
telescope.
(b) Using any part of the reticule of the elbow telescope,
such as the left edge of the letter N, repeat test d (2) .
<3) Range quadrant for elevation and angle of site. — (a)
Lay the tube horizontal and level the trunnions.
(b) Center both bubbles.
(c) If the elevation scale is not at zero, loosen, the three
screws in the end of the micrometer knob, hold the knob, and
slip the micrometer until its zero graduation and the index
are in agreement. Retighten the screws.
id) If the angle of site does not indicate 300, loosen the
screw in the end of the micrometer knob, hold the knob, and
slip the micrometer until the zero graduation and the index
are in agreement. Retighten the screw.
(4) Elbow telescope. — (a) Level the carriage trunnions and
the tube with the gunner's quadrant.
(b) Bore-sight, placing the test target in alinement with
the bore, or note a distant terrain object which is in aline-
ment.
(c) Look through the elbow telescope. The line marked N
should be on its proper part of the target (6.42 inches above
axis of bore) . If not in adjustment return it to the ord-
nance maintenance company for repair.
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51
SERVICE OF THE PIECE
(d) With the azimuth indexes coinciding, the center oi\
the telescope (clear space between horizontal lines) should
be on its proper portion of the testing target or distant
object. If the telescope points to the right of the bore-
sighted target, put it on the target by loosening the locking
nut and adjusting the headless screw on the range quadrant
bracket. If the telescope points to the left of the bore-
sighted target, put it on with the azimuth-worm knob, loosen
the two set screws, and slide the movable azimuth index
until it coincides with the fixed index.
/. Bracket fuze setter, M1916A2. — (1) To eliminate loose-
ness in either worm gear, loosen the set screw, and with a
serew driver turn the adjusting plug clockwise. Retighten.
the set screw. The range crank should not fall on its own
weight.
(2) To eliminate end play in either worm shaft, remove the
crank handle or knob by driving out the tapered pin, loosen
the set screw, and tighten the bearing cap with a teat wrench. "
Retighten the set screw. Replace the handle or knob.
o
58