Document text
FM 6-55
MHI
Copy 3 i —
WAR DEPARTMENT
FIELD ARTILLERY
FIELD MANUAL
SERVICE OF THE PIECE
75-MM GUN, M2, HORSE-DRAWN
AND TRUCK-DRAWN
a<Lr /939
FM 6-5i*
FIELD ARTILLERY
FIELD MANUAL
SERVICE OF THE PIECE
75-MM GUN, M2, HORSE-DRAWN
AND TRUCK-DRAWN
Prepared under direction of the
Chief of Field Artillery
UNITED STATES
GOVERNMENT PRINTING OFFICE
WASHINGTON: 1939
For Bale by the Superintendent of Documenta, Washington, D. C. - Price 10 cents
WAR DEPARTMENT,
Washington, October 1, 1939,
FM 6-55, Field Artillery Field Manual, Service of the
Piece — 75-mm Gun, M2, Horse-drawn and Truck-drawn, is
published for the information and guidance of all concerned.
[A. G. 062.11 (6-17-39).]
By order op the Secretary op War:
G. C. MARSHALL,
Chief of Staff,
Ofpicial:
E. S. ADAMS,
Major General,
The Adjutant General,
TABLE OF CONTENTS
Section I. General, Paragraph Page
Purpose and scope 1 1
References * 2 1
Definitions and terms- * 3 1
II. Organization.
Composition 4 2
Forma-tion 5 3
III. Posts; mounting and dismounting.
Posts of the gun squad 6 3
To post the gun, squads 7 4
Posts of the cannoneers 8 4
To post the cannoneers 9 4
To mount the cannoneers 10 4
To dismount the cannoneers 11 6
IV. Movements of the carriages by hand.
Limbered or coupled 12 7
Unlimbered or uncoupled 13 7
V. Unlimbering and limbering.
Unlimbering 14 8
Limbering 15 11
VI. Uncoupling and coupling.
Uncoupling 16 13
Coupling 17 14
VII. Preparation for action and march order.
To prepare for action 18 14
Posts of the cannoneers, carriages un-
limbered (uncoupled) 19 18
March order 20 19
VIII. Duties in firing.
General 21 22
Chief of section 22 23
Gunner 23 27
No. 1 24 32
No. 2 25 36
No. 3 26 37
No. 4 27 39
No; 5 ' 28 40
IX. Additional information on the service of
the piece.
Accuracy in laying 29 41
Fire at will 30 42
Aiming stakes 31 42
Correction for lateral displacement 32 43
Reporting errors 33 43
Cease firing 34 43
Suspend firing 35 43
Changes in data during firing 36 44
To unload the piece 37 44
Misfires 38 44
Ammunition 39 44
III
TABLE OF CONTENTS
Paragraph Page
Sec. IX. Additional information on the service of
the piece — Continued.
The section data board 40 45
Firing- Jack floats 41 45
Firing from the wheels 42 45
X. Care and maintenance of materiel.
General 43 46
Cleaning 44 47
Lubrication 45 50
Protection against chemicals 46 50
Recoil mechanism 47 50
Barrel assembly, breech mechanism, and
firing mechanism 48 52
Cleaning slides 49 54
Dismounting recoil mechanism from
carriage and care of trunnion bear-
ings 50 55
Equilibrators 51 56
Wheels and wheel bearings 52 66
Brake mechanism 53 57
Firing Jack 54 57
Automatic pole support on the M1918
limber 55 58
Caisson band brake 56 58
Sighting and fire-control equipment 57 59
FM6-55
FIELD ARTILLERY FIELD MANUAL
SERVICE OF THE PIECE
75-MiyC GUN, M2, HORSE-DRAWN 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 gun section of the firing battery.
■ 2. References. — a. Description, operation, functioning, and
care of materiel . — (1) TR 1305-A; SNL C-5.
(2) TR 1305-75A (now TR 320-95) ; SNL C-12.
b. DescriptUm and operation of fire-control and sighting
equipment. — TR 1320-C (now TR 310-20) ; SNL F-22; SNL
P-166.
c. Ammunition. — ^TR 1355-75A; TR 1370-A; SNL Rr-1; SNL
Rr-3.
d. Cleaning and preserving materials . — TR 1395-A; SNL
K-1.
e. The field artillery driver. — ^Part Two, FM. 6-5.
/. Maneuvers of the battery. — ^Part Two, FM 6-5.
g. Safety pyrecautions in firing. — AR 750-10; Chapter 4, PM
6-40.
h. The firing battery. — Chapter 1, FM 6^0.
i. Gunnery. — ^FM 6-40.
j. Reconnaissance, occupation, and organization of posi-
tion. — Part One, FM 6-20.
■ 3. Definitions and Terms. — a Section. — Tables of Organ-
ization prescribe the personnel and materiel comprising a
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 gun section is composed of one piece and
1
3-4
SERVICE OP THE PIECE
the additional materiel and the personnel required to serve
that piece.
h. Limbered. — A piece (caisson) is said to be limbered when
its lunette is attached to the pintle of its limber.
c. Urdimhered. — piece (caisson) is said to be unlimbered
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 ileft). — ^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 gun when it is in its normal firing position.
Section II
ORGANIZATION
■ 4. Composition. — a. Gun squad. — ^A gun squad consists of
the gunner and five cannoneers numbered from 1 to 5. The
remaining cannoneers of the gun section act as reliefs or
are aligned such other duties as the chief of section may
direct. When the battery unlimbers or uncouples for drill
or for firing, the chief of section remains at the firing position
and commands the gun 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
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 -numbered
cannoneers being assigned to the first caisson.
2
SERVICE OF THE PIECE
4-6
(2) Posts and movements prescribed hereinafter for the
gun squad apply, v?ith obvious modifications, to an ammuni-
tion squad.
■ 5. Formation. — a. Order of formation, — gxm squad is
formed as shown in figure 1. Higher-numbered cannoneers,
if present, form in order on the left of No. 5.
h. To form. — (1) The place of formation is indicated and
the command given thus, for example: 1. in front (rear)
OF YOTIR PIECES (CAISSONS), Or 1. ON THE ROAD FACING THE PARK,
2. FALL IN. Each gunner repeats the command 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 atten-
IsUhlalijol
Figure 1. — Formation of the gun squad.
tion in their proper places. For the first formation of the
gun squads for any drill or exercise, the caution, ‘'As gun
squads,” precedes the command. The chief of section, if
present, supervises the formation.
(2) In case the front or rear of the carriages is designated,
each squad falls in at its post (par. 6) .
c. To call off. — (1) The command is: CALL OFF. The
cannoneer on the left of the gunner calls off “One”; the can-
noneer on the left of No. 1, “Two”; and so on.
(2) After having called off, if a subsequent formation is
ordered, the cannoneers fall in at once in their proper order.
Section III
POSTS* MOUNTING AND DISMOUNTING
■ 6. Posts of the Gun Squad. — a. Carriages limbered or
coupled. — (1) 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, from the heads of the lead horses, or from
the front of the truck.
3
6-10
SERVICE OF THE PIECE
(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.
h. Carriages unlimbered or uncoupled. — ^The squad is in
rear of the piece, in line facing to the front, its center two
paces from the end of the trail of the piece.
■ 7. To Post the Gun Squads. — ^The squads having been
marched to the vicinity of the carriages are posted at the
command squads in front (rear) of your pieces (caissons).
Each gunner marches his squad to its carriages and posts it
in the position indicated.
■ 8. Posts op the Cannoneers.— a. Carriages limbered or
coupled. — ^The cannoneers of the gun squad are posted as
shown in figures 2 and 4. All are 2 feet outside the wheels
and facing to the front. Higher-numbered cannoneers, if
present, are posted as prescribed by the chief of section.
b. Carriages unlimbered or uncoupled. — See paragraph 19.
■ 9. To Post the Cannoneers. — a. The command is: 1. can-
noneers, 2. POSTS. Each gunner repeats the command
POSTS. The cannoneers leave the ranks, if formed, and move
at the double time to their posts.
b. 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.
The command is general, however, and is applicable when
the cannoneers are in or out of ranks, at a halt or marching,
and when the carriages are limbered (coupled) or unlimbered
(uncoupled) .
■ 10. To Mount the Cannoneers. — a. (1) Horse-drawn bat-
teries. — ^In each gun squad the personnel is mounted as
shown in figure 3. Higher-numbered cannoneers are
mounted as prescribed by the chief of section.
(2) Truck-drawn batteries. — ^In each squad the personnel
is seated in the body of 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.
4
10-11 SERVICE OP THE PIECE
(1) Horse-drawn batteries , — ^At the first command, the
cannoneers who mount the limber chests and those who
mount the caisson chests move at the double time to the
rear and front of those chests, respectively. Each cannoneer
who mounts the limber chest, except No, 2, places the foot
nearest the wheel on the step, grasps the chest handle with
the hand nearest the wheel, and with the other hand grasps
the hand of the cannoneer opposite him. Each cannoneer
who mounts the caisson chest places the foot farthest from
the wheel on the caisson trail, and grasps the chest handle
with the hand nearest the wheel and the hand of the can-
noneer opposite him with the other hand. At the second
command, all except No. 2 spring up and seat themselves,
faced to the front. No. 2. then mounts and seats himself
between the gunner and No. 1. Higher-numbered cannoneers,
if present, mount as prescribed by the chief of section.
(2) Truck-dranwi 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 moimt as prescribed by the battery commander.
c. If the command is: 1. cannoneers, 2. MOUNT, the can-
noneers execute, at the command mount, 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-drawn batteries. — ^At the first command, the
cannoneers seated on the chests stand up on the footboards;
at the second command, all jump to the ground and take
their posts at the double time.
(2) Truck-drawn 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.
6
SERVICE OF THE PIECE
12-13
Section IV
MOVEMENTS OP THE CARRIAGES BY HAND
■ 12. Limbered or Coupled. — a. Horse-dravm batteries, — (1)
To the front . — ^The command is: 1. pieces (caissons) for-
ward, 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 6 to the limber wheels; and Nos. 3 and 4 to the
piece (caisson) wheels; higher-numbered cannoneers, if pres-
ent, to posts as directed by the chief of section; the gunner
and the even numbers working on the right side of the
carriage, odd numbers on the left. When the piece is to be
moved. No. 3 releases the brake. When the caisson is to be
moved. No. 4 releases the brake; when the brake is released.
Nos. 3 and 4 raise and secure the caisson prop. At the com-
mand MARCH, all assist in moving the carriage to the front.
At the command halt, the carriage is stopped. In the case
of the piece. No. 4 sets the brakes. In the case of the cais-
son, 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 at the command march the cannoneers
move the carriage to the rear.
b'. TrticJc-dratm batteries . — ^The carriages are not moved
by hand when coupled.
■ 13. Unlimbered or 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.
(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 and down
7
13 - 14 : SERVICE OF THE PIECE
steep slopes, the gunner assists 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 sets the brakes, and all resume
their posts (par. 19).
b. Caisscm . — ^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 footboard 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
UNUMBERING AND LIMBERING
■ 14. Unlimbering. — a. Disposition of the carriages. — (1)
Before unlimbering . — ^The piece and its caisson are placed
abreast of each 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 in-
tended 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 about 1 yard apart, trails of the
piece and the caisson pointing to the rear, the piece on the
right and about 1 foot in advance of the caisson.
(b) Normally, the piece is placed slightly in advance to
allow for recoil at the first shot, which ordinarily is about
1 foot.
(c) In emergencies the caisson may be placed temporarily
on the right of the piece. As this position is not favorable to
the service of ammunition, the caisson should be moved to the
left of the piece as soon as practicable.
8
SERVICE OP THE PIECE
14
id) 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 inter-
vals between them.
b. To unlimber. — (1) General . — ^In unlimbering to fire to
the front or rear, the caisson establishes the position; in im-
limbering to fire to the flank, the element (pieces or caisson)
on the side toward which fire is to be directed establishes the
position. If the carriages, after unlimbering, have to be
moved by hand, each carriage is moved, as prescribed in para-
graph 13, in the order designated by the chief of section. If
the teams are not hitched, the carriages are unlimbered suc-
cessively, the one which establishes the position being unlim-
bered first. Limbers are moved to their position by can-
noneers designated by the chief of section.
(2) To /ire 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. The cannoneers, if mounted, dismount after the
carriages have halted.
(a) 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 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.
(b) The piece . — ^The gunner and No. 1 hasten to the trail
handles; No. 2 grasps 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.
9
14
SERVICE OF THE PIECE
The gunner and No. 1 carry the trail away from the caisson,
and all the cannoneers working together turn the piece 180®*
The gunner causes the piece to be placed beside the caisson
(a (2) above). No. 1 releases the drawbar lock and turns
the drawbar 180®, latching it in the firing position; the
gunner and No. 1 then lower the trail to the ground. No. 2
sets the brakes, and all the cannoneers at the piece take
their posts (pars. 18c and 19) .
(c) 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 erid of the pole
if teams are not hitched) will be 25 yards from the rear of
the caisson. 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 sec-
tion, caisson on the right, the command is: ACTION REAR.
If marching, the carriages halt at the command or signal.
The cannoneers, if mounted, dismount after the carriages
have halted.
(a) 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 drive on. No. 3,
assisted by No. 4, then lowers the caisson prop; No. 4 sets the
brake, and Nos. 3 and 4 take their posts.
(b) 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 commands
or signals drive on. All working together place the piece
beside the caisson (a (2) above). No. 1 releases the draw-
bar lock and turns the drawbar 180®, latching it in the firing
position; the gunner and No. 1 then lower the trail to the
groiuid. No. 2 sets the brakes and the cannoneers at the
piece take their posts (pars. 18c and 19) . Higher-numbered
10
SERVICE OP THE PIECE
14r-15
cannoneers, when present, assist in the movement as di-
rected 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, moves to the rear, executes a left-about, and halts
so that the heads of the lead horses (or the end of the pole
if the teams are not hitched) will be 25 yards from the rear
of the caisson. 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.
(4) To fire to the fiank. — (a) The carriages being in
double section, the caisson on either side of the piece, the
command is: ACTION RIGHT (IiEPT). The movement is
executed according to the principles of action front and
ACTION rear, with the following modifications. After the
carriages are unlimbered, the muzzle of the piece is turned
in the direction of fire and the trail of the caisson in the
opposite direction; the carriage in rear is run up to its
proper position on the line. The carriage on the side toward
which fire is to be delivered is first established in position,
and then all the cannoneers assist in bringing the carriage
in rear up to its proper position (a (2) above) .
(b) At the command or signal drive on, the limbers take
their prescribed positions. To take post in rear of the
carriages, the limber away from the flank toward which fire
is to be delivered moves out first, wheels away from the
direction of fire, and after having gained sufiicient 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.
■ 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) No. 4 releases the caisson 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
11
15
SERVICE OP THE PIECE
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 follows: The gunner releases the brakes and the gunner
and No. 1 then 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. 1 and faces to the
rear. Nos. 3 and 4 place themselves with their backs toward
the caisson chest close up against the footboard, No. 4 on
the right and No. 3 on the left of the trail. Higher-num-
bered 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 limber has halted in prolongation
of the trail, the gxmner 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 raise the trail and
place the lunette in the traveling position and 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 lim-
bered (fig. 2).
b. To limber rear . — ^The carriages being in position and in
march order (par. 20), the command is: UMBER REAR.
(1) No. 4 releases the caisson brake; Nos. 3 and 4 raise and
secure the caisson prop. All cannoneers working together
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 (1) above).
(2) The limbers are brought up and the limbering is com-
pleted as prescribed in a (2) above.
12
SERVICE OF THE PIECE
IS
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 con-
cealment are available, they are located in rear of either
flank, faced to the front, with wide intervals between them.
b. 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. No. 5 releases the drawbar lock and turns
the drawbar 180®, latching it in the firing position; Nos. 2
and 5 then lower the trail to the ground. Prior to the turn,
the gunner sets the brake on the pivot wheel (the wheel ad-
jacent to the gunner’s post) and when the turn is completed
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 section. 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 unload-
ing. 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 un-
coupling.
175727®— 39 ^3
13
16-18 SERVICE OF THE PIECE
d. To fire to the flank , — ^The command is : ACTION RIGHT
<LEPT) . The movement is executed according to the prin-
ciples of ACTION FRONT, With the following modifications:
After uncoupling, the trail is turned 90° away from the direc-
tion 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 march
order, the command is: COUPLE. The trucks, under 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 unexpended
ammunition. Then Nos. 2 and 5 hasten to- the trail handles.
The gunner releases 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 5 raise the trail and
place the lunette in the traveling position and over the pintle.
No. 2 latches the pintle. All cannoneers take their posts
(par. 8) .
Section VII
PREPARATION FOR ACTION ANO MARCH ORDER
■ 18. To Prepare for Action. — a. The carriages being in posi-
tion unlimbered or uncoupled, the command is: PREPARE
FOR ACTION. Duties of individuals are as follows :
(1) Chief of section, — (a) Supervises the work of the can-
noneers.
(b) Inspects the materiel, verifies the fact that the recoil
mechanism contains the proper amount of oil (TR 1305-75A
(now TR 320-95) ), and, when the operations have been com-
pleted, reports to the executive, "‘Sir, No. (so and so) in order,”
or reports any defects which the section cannot remedy with-
out delay.
(2) Gunner. — (a) Removes the left brake co\"er and places
it on top of the caisson (horse-drawn imits) , or places it on
14
SERVICE OP THE PIECE 18
the ground outside the left wheel (truck-drawn units), and
sets the brakes.
(b) Removes the left trail pin and, assisted by No. 2, sets
the pin in the 90° position (or in the 45° position when spe-
cifically so ordered by the executive) .
(c) Assists Nos. 1, 2, and 5 in removing the gim cover.
(d) Removes the sight bracket cover and places it on the
caisson (horse-drawn units), or on the ground outside the
left wheel (truck-drawn units) .
(e) Releases the sight-bracket traveling lock and raises
the sight and bracket to the firing position.
(/) Removes the sight from its case and seats it in the
sight bracket.
(fir) Engages the sight-bracket gears by means of the throw-
out lever; uncovers the sight-bracket leveling bubbles; sets
the tilting head at zero, the deflection at zero, and levels the
bubbles.
(7i) Assists No. 2 in releasing the traveling lock by releas-
ing the pressure on the pin by means of the traversing hand-
wheel, and leaves the gun in the center of the traversing arc.
(O Takes his post.
(3) No. 1. — (a) Removes the right brake cover and places
it outside the right wheel,
(b) Removes the right trail pin and, assisted by No. 5, sets
the pin in the 90° position (or in the 45° position when spe-
cifically so ordered by the executive) .
(c) Assists the gunner and Nos. 2 and 5 in removing the
gun cover.
id) Assists No. 2 in unlocking the firing jack from the
cradle by elevating the gim slightly.
(e) Removes the range -quadrant cover and places it out-
side the right wheel.
(/) Sets site 300 and levels the bubble.
(g) Sets range 3,000 and matches the elevation pointers by
means of the elevating handwheel.
ih) Removes the breech cover and places it outside the
right wheel.
(i) Operates the breech mechanism; sets the safety piece
in the firing position.
15
18 SERVICE OF THE PIECE
(?) Examines the breechblock, chamber, and bore, clean-
ing any parts requiring it; leaves the breech open.
ik) Removes the sponge-and-rammer staff from the trav-
eling position, assembles it, and places it to the right of the
piece.
(7) Takes his post.
(4) No, 2. — (a) Releases the trail lock and swings the. left
trail into the 90® position (or into the 45° position when
specifically so ordered by the executive), while the gunner
sets the trail pin.
(b) Removes the left trail handspike, carries it around
the left side of the gun, and places it conveniently beside
the firing jack.
(c) Unbuckles the left side gun cover straps and assisted
by the gunner and Nos, 1 and 5, removes the gun cover.
(d) Assisted by No. 1 who elevates the piece, and by the
gunner who traverses the piece slightly, releases the travel-
ing lock and unlocks the firing jack from the cradle.
(e) Depresses the firing-jack pedal and swings the jack
forward and downward, locking it in the firing position.
(/) Using the two trail handspikes, elevates the firing
jack.
(g) Sets the traversing control plunger for 90° traverse
(or for 45° traverse when specifically so ordered by the
executive) .
ih) Removes the handspikes from the jack, leaves the
right handspike on the right side of the jack where it is
convenient for lowering the jack, and returns the left hand-
spike to its firing position in the trail.
(O Takes his post.
(5) No, 3, horse-drawn units, — (a) Assists No. 4 to lower
the caisson apron and to raise the caisson door.
(b) Opens the fuze setter, leaving it in the raised position.
(c) Removes the fuze-setter cover, placing it on the cais-
son.
(<Z) Sets the fuze-setter scales at corrector 30, range 3,000.
(e) Takes his post.
(6) No. 3, truck-dravm units . — (a) Places the fuze setter
in position.
(b) Sets the fuze-setter scales at corrector 30, range 3,000
16
SERVICE OF THE PIECE
18
(c) Puts a round of shrapnel in the fuze setter.
id) Assisted by No. 4, arranges the ammunition and tools
in an orderly and convenient manner to the left of the
piece.
(c) Takes his i>ost.
(7) No, 4, horse-drawn units, — ia) Assists No. 3 to lower
the caisson apron and to raise the caisson door.
(b) Takes a fuze box from the ckisson rack and places it
on the footboard.
(c) Puts a round of shrapnel in the fuze setter.
id) Takes his post.
(8) No, 4, truck-drawn units. — ia) Assists No. 3 to ar-
range the ammunition and tools.
(b) Takes his post.
(9) No, 5. — (a) Swings the right trail into the 90° posi-
tion (or the 45° position when specifically so ordered by the
executive) ^ while No. 1 sets the trail pin.
(b) Removes the right trail handspike, carries it around
the right side of the gim, and places it conveniently on the
ground to the side of the firing jack.
(c) Unbuckles the right side gun cover straps, and as-
sisted by the gunner and Nos. 1 and 2 removes the gun
cover, folds it neatly, and places it on the ground 1 yard
to the right of the right piece wheel.
id) Removes the muzzle cover, and places the muzzle
cover, right brake cover, range -quadrant cover, breech
cover, and rammer neatly on top of the gun cover, m truck-
drawn units, also places the sight-bracket cover and left
brake cover on the gun cover.
ie) Removes the aiming stakes and places them, beside the
sponge-and-rammer staff, or sets out the aiming stakes when
so directed by the chief of section.
(/) Distributes waste to the cannoneers.
i0 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-
17
18-19 SERVICE OF THE PIECE
riages in position, preparation for action is completea without
command, and the cannoneers take their posts for firing the
piece.
c. If PREPARE FOR ACTION has not been ordered before the
carriages are established in the firing position, the command
habitually is given by the chief of section as soon as the car-
riages have been unlimbered (uncoupled) . In case this is not
desired, the caution, “Do not prepare for action,” must be
given.
■ 19. Posts of the Cannoneers, Carriages Unlimbered (Un-
coupled) . — a. The carriages having been unlimbered (uncou-
pled), posts are taken as follows:
(1) Chief of section. — ^The chief of section goes where he
can control the service of the piece, hear commands, and
perform his duties, effectively. A convenient post is at the
end of the trail on the side opposite the executive.
(2) Gunner. — ^Immediately to the left of the breech, be-
hind the axle (inside or outside the trail, depending upon
the traverse of the piece).
(3) No. 1. — Immediately to the right of the breech, be-
hind the axle (inside or outside the trail, depending upon
the traverse of the piece).
(4) No. 2. — ^Two feet in rear of the gunner, covering him.
(5) No. 3, horse-drawn units. — ^Two feet in rear of the
caisson chest, on the right of the caisson trail. .
(6) No. 3, truck-drawn units. — ^Two feet to the left of and
opposite the rear of the left piece wheel.
(7) No. 4. — ^Two feet in rear of No. 3, covering him.
(8) No. 5, horse-drawn units. — ^Two feet in rear of the
caisson chest, on the left of the caisson trail.
(9) No. 5, truck-drawn units. — ^Two feet to the left of
No. 4.
b. At drill all stand at attention at their posts (fig. 5),
facing the front. In firing and in combat, minor modifica-
tions of these posts are required for the more efficient per-
formance of the duties in the service of the piece and to
secure the protection afforded by the materiel. Higher-
numbered cannoneers, if present, take posts as prescribed by
the chief of section.
18
SERVICE OP THE PIECE
19-30
c. In order to exercise the cannoneers in all the duties
connected 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 car-
riages being unlimbered (uncoupled) and prepared for action,
to resume the order for marching, the command is: MARCH
‘ORDER. Duties of individuals are as follows:
(1) Chief of section. — (a) Supervises the work of the
cannoneers.
(b) Inspects the materiel; makes sure that the piece is not
left loaded and that the traveling locks are set for traveling;
PiGtTBE 5. — ^Posts of the cannoneers, carriages unlimbered, horse-
drawn unit.
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) Sets the tilting head and deflection at
zero and closes the covers on the sight-bracket leveling
bubbles.
(b) Removes the sight from its bracket, returns it to its
case, and locks the case.
(c) Disengages the sight-bracket gears and turns the sight
bracket to the traveling position.
id) Engages the sight-bracket lock in the traveling posi-
tion.
19
20
SERVICE OP THE PIECE
(e) Traverses the piece to the center of the traversing arc,
assisting No. 2 in locking the firing jacket in the traveling
position.
(/) Traverses slightly right and left, while No. 2 secures the
traveling lock.
(g) Withdraws the left trail pin and puts it in its traveling
position while No. 2 closes the trail.
ih) Replaces the sight-bracket and left-brake covers, which-
have been handed him by No. 2 (horse-drawn units) or No. 5
(truck-drawn units) , on the sight bracket and left brake (after
first releasing the brakes) .
(i) Assists Nos. 1, 2, and 5 in replacing the gun cover on the
gun.
(;) Takes his post.
(3) No, 1. — (a) Sets the angle of site at 300, and levels the
angle-of-site bubble.
(b) Closes the cover of the angle-of-site bubble.
(c) Closes the breech and sets the safety piece in the
traveling position.
(d) Unscrews the sponge-and-rammer staff, and places it
in the traveling position.
(e) Assists No. 2 in locking the firing jack in its traveling
position by depressing the piece.
(/) Withdraws the right trail pin and puts it in its traveling
position while No. 5 closes the trail.
(р) Replaces the range-quadrant, breech, and right brake
covers, which have been handed to him by No. 5.
ih) Assists the gunner and Nos. 2 and 5 in replacing the
gun cover.
(i) Takes his post.
(4) No. 2. — (a) Takes the right trail handspike from its
position at the side of the jack and inserts it into the jack.
(b) Releases the firing jack, permitting the piece to drop
on its wheels, and hands the right trail handspike to No. 5.
(с) Swings the jack forward and upward, and, assisted by
the gunner and No. 1 on the traversing and elevating hand-
wheels, locks the jack in the traveling position.
id) Assisted by the gunner on the traversing handwheel,
secures the traveling lock in its traveling position.
20
SERVICE OP THE PIECE
20
(e) In horse-drawn units only, hands the sight-bracket and
left-brake covers to the gunner.
(/) Removes the left trail handspike and secures it in its
traveling position.
(gr) Raises the left trail and moves it to its closed position
while the gunner removes the left trail pin.
ih) Locks the trails in the traveling position.
(i) Assists the gunner and Nos. 1 and 5 in replacing the
gun cover on the gun.
(^) Takes his post.
(5) JVo. 3, horse-drawn units, — (a) Sees that any fuzes
which have been get are set back at safe.
(b) Sets the fuze setter at corrector 30, range 3,000.
(c) Returns unused fuzes to the fuze box.
(d) Replaces the fuze-setter cover.
(e) Secures the fuze setter in the traveling position.
(/) Assists No. 4 to lower and secure the caisson door, and
to raise and secure the caisson apron.
(gr) Takes his post.
(6) JVo. 3, truck-drawn units, — (a) Sees that any fuzes
which have been set are set back at safe.
(b) Sets the fuze setter at corrector 30, range 3,000.
(c) Returns unused fuzes to the fuze box.
(d) Replaces the fuze setter in the box.
(e) Assisted by No. 4, prepares ammunition and tools for
loading into the truck. He will assure himself that all fuzes
have been set at safe.
if) Takes his post.
(7) No. 4, horse-drawn units, — (a) Assists No. 3 in setting
fuzes back at safe.
(b) Replaces or otherwise disposes of unused ammuni-
tion. Before replacing any round in the caisson chest, he
will assure himself that the fuze is set at safe.
(c) Runs around the left of the caisson and replaces the
fuze box in the caisson rack.
(d) Assists No. 3 to lower and secure the caisson door, and
to raise and secure the caisson apron.
(e) Takes his post.
(8) No. 4, truck-drawn units. — ia) Assists No. 3 to pre-
pare ammunition and tools for loading into the truck.
175727°— 39 4
21
20-21
SERVICE OP THE PIECE
(&) Takes his post.
(9) No, 5. — (a) Replaces the muzzle cover.
(b) Takes the right trail handspike from No. 2, passes
around the right side of the piece, handing the breech, range-
quadrant, and right brake covers to No. 1 on his way, and
secures the right trail handspike in its traveling position;
in truck-drawn units, hands the sight-bracket cover and left
brake cover to the gunner.
(c) Secures the aiming stakes.
id) Raises the right trail and moves it to its closed posi-
tion while No. 1 removes the right trail pin.
(e) Secures the gun cover and assists the gunner and Nos.
1 and 2 in replacing it on the gun.
if) Takes his post.
b. To resume fire in another position, — (1) If it is in-
tended to resume firing shortly, but in another position, so
that the limbering (coupling) of the pieces is necessitated,
the command march order is not given. In this case, at the
command for limbering (coupling) , only such of the opera-
tions 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.
Section VIII
DUTIES IN FIRING
■ 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, opens and
closes the breech, lays for elevation, and fires the piece.
(4) No, 2 loads the piece.
22
SERVICE OP THE PIECE
21-22
(5) No. 3 operates the fuze setter and screws fuzes in
sheU.
(6) No. 4 prepares ammunition and passes rounds to No. 2
for loading; in time fire he keeps rounds in the fuze setter
and sets the fuze.
(7) No. 5 prepares ammunition for firing, and in direct
laying at moving targets levels the angle-of-site bubble and
sets the range.
b. The duties of the gunner and Nos. 1 and 2 are mutually
dependent. The same is true of Nos. 3, 4, and 5.
■ 22. Chief op 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 re^
ferring point, or the target.
(5) To follow fire commands.
(6) To indicate when the piece is ready to fire.
(7) To give the command to fire, except when firing at
moving targets with direct laying.
(8) To report errors and other unusual incidents of fire
to the executive.
(9) To conduct prearranged fire 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.
(13) To conduct the fire of his piece on a moving target,
when so ordered by the executive.
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 the
index arm opposite the 360 mark of the graduated arc on the
quadrant frame and slides the slide level along the index
23
22 SERVICE OF THE PIECE
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, the clamp is tightened just sufficiently to hold
the slide in place.
(b) 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 on the breech hoop, 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 important that he take the same position
and hold the quadrant in the same manner for each subse-
quent setting, so that the quadrant bubble will in each case
be viewed from the same angle.
(d) No. 1 operates the elevating handwheel until the quad-
rant bubble is centered, making sure that his last movement
is in the direction in which it is most difficult to turn the
handwheel. (Up to about 400 mils' elevation or 7,500 yards’
range setting, this is in the direction of decreasing eleva-
tion; otherwise in the direction of increasing elevation.)
The chief of section warns No. 1 when the bubble is ap-
proaching 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 sec-
tion 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
24
SERVICE OF THE PIECE 22
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 elevatibn thus
set, for example, “Elevation, No. (so and so), (so much).”
(3) To measure the minimum elevation or minimum
range.
(a) 1. Elevation. — ^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 crest. 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, “Mini-
mum elevation, No. (so and so) , (so much) .”
2. Range. — ^The command is: MEASURE THE MINI-
MUM RANGE, SITE (SO MUCH) . The chief of
section causes No. 1 to set the site announced
and to center the angle-of-site bubble. Sighting
along the lowest element of the bore, he then
causes No. 1 to operate the elevating handwheel
until the line of sight just clears the crest. No. 1
then matches the elevation pointers by operating
the range drum and reads the range setting.
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) .”
(b) When the executive announces the corrected minimum
elevation or the corrected minimum range and site, the
chief of section records it in a notebook and causes the gun-
ner to chalk it on a convenient place on the carriage.
(4) To indicate to the gunner the aiming point, the re-
f erring point, or the target. — ^Whenever an aiming point, a
referring 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 indi-
cate it to the gunner. If there is any possibility of mis-
understanding, the chief of section will turn the sight until
the horizontal and vertical hairs are on the point designated.
25
22 SERVICE OF THE PIECE
(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 vertically 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. 1 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 of section
will not give the signal or command to fire until all the can-
noneers are in their proper places. He will regvlre the can-
noneers to stand clear of the piece for the first romid.
(8) To report 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 re(iuest instructions
(par. 32). Likewise, other unusual incidents that affects the
service of the piece are promptly reported by the chief of
secti(>n.
(9) To conduct prearranged fire schedtdes . — ^Whenever the
execution of prearranged fires is ordered, the chief of section
will conduct the fire of his section in strict conformity to the
schedule 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 elevations; base deflec-
tions, including aiming points used; prearranged fires when
28
SERVICE OF THE PIECE
22-23
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 functicming of the 'mate^
riel, — The functioning of all parts of the materiel will be ob-
served closely during firing. Before the piece is flred, the
chief of section verifies the fact that the recoil mechanism
contains the proper amount of oil and thereafter carefully
observes the fimctioning 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.
(13) During direct laying an a moving target, to conduct
the fire of his piece when so ordered by the executive , — (a) To
announce an initial lead, — ^The chief of section observes the
target, estimates its lateral speed, and, based thereon, the
lead in mils, and announces the lead to the gunner; for ex-
ample, LEAD RIGHT (LEFT) (SO MUCH) . The neccssary lead at
any range may be taken as one mil for each mile-per-hour
lateral speed of the target. Another method is to measure in
mils the lateral movement of the target while counting four in
quick- time cadence (2 seconds) ; this will give the proper
lead for a range of 1,000 yards. The count is decreased pro-
portionately for ranges less than 1,000 yards, increased pro-
portionately for ranges greater than 1,000 yards. If the lead
is observed to be in error, or if the speed or direction of move-
ment changes during firing, a new lead is announced.
(b) To announce an initial site, — ^The chief of section esti-
mates the angle of site of the target and announces it to
No. 1.
(c) To announce an initial range, — ^The chief of section
estimates the initial range of the target and announces it to
No. 5. During the firing he announces range changes as
appropriate.
■ 23. Gunner. — a. Enumeration of duties, — (1) (a) To cen-
ter the bubbles on the sight mount.
(b) To set or change the deflection.
27
23
SERVICE OF THE PIECE
(c) To apply the deflection difference.
id) To lay for direction.
(e) To call “Ready.”
if) To refer the piece.
ig) To record base deflection.
ih) To measure a deflection.
ii) To take and maintain an announced lead in tracking
the target during direct laying on a moving target.
ij) To give the command to fire, during direct laying on a
moving target.
(2) For indirect lasnng or direct laying on a stationary
target, the gunner performs the duties prescribed in (1) (a) ,
(b) , (c) , id) , and ie) above.
(3) For direct laying on a moving target, the gunner per-
forms the duties prescribed in (1) (a), (i), and ij) above.
(4) When directed, the gunner performs the duties pre-
scribed in (1) (/) , ig) , and ih) above.
b. Detailed description of certain duties, — (1) To set or
change the deflection. — ia) 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, for
example, deflection i, 885, the gunner first sets the zero of
the azimuth micrometer opposite the fixed azimuth index, if
it is not already so set. He then pushes the throw-out lever
with his left hand and with his right hand turns the rotating
head until the himdreds’ 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 to the left until the micrometer index is opposite the
graduation 85 of the counterclockwise graduations on the
azimuth micrometer. The line of sight will then make a
horizontal angle of 1,885 mils with the axis of the bore. The
azimuth micrometer is then turned imtil its zero graduation
is opposite the micrometer index. Any movement of the azi-
muth micrometer does not change a deflection previously set.
(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 deflection
then will indicate the direction in which he should move his
28
SERVICE OP THE PIECE
23
thumb in turning the azimuth-worm knob. He also should
be taught that turning the azimuth-worm knob to the right
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 to the
left 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 es, the gunner turns the azimuth-worm knob
by moving his thumb to the right until the micrometer index
has moT^ed from zero to 65 on the clockwise graduations of
the azimuth micrometer. As turning the azimuth- worm knob
to the right decreases the deflection, the resulting deflection
will be 1,820 mils. The azimuth micrometer is then reset with
its zero opposite the micrometer index. Should the command
be LEFT (SO MUCH), the deflection setting is changed in a
similar manner, except that the gunner moves his thumb
to the left and follows the counterclockwise graduations of
the azimuth micrometer.
(2) To apply the deflection difference. — (a) The command
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 speci-
fied 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.
(b) If the command is, for example, on no. i open 5, the
gunner on No. 1 makes no change; the gunner on No. 2 turns
the azimuth-worm knob by moving his thumb to the left,
avxiy from the piece indicated in the command, 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 also 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, on no. s close lo,
the gunner on No. 1 turns the azimuth- worm knob by moving
his thumb to the left, toward the piece indicated in the com-*
175727'*— 39 5
29
23
SERVICE OP THE PIECE
mand, 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 azi-
muth-worm knob by moving his thumb to the right and sets
off 10 mils once.
id) It should be noted that, in making the deflection
changes involved in applying the deflection difference, each
gunner turns the azimuth-worm knob by moving his thumb
away from the piece indicated if the command is open, and
toward the piece indicated if the command is close; also that
the muzzles of the pieces will be moved in similar directions
when the pieces are laid after the deflection difference has
been set.
(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 so, on no.
1 CLOSE 5, both of which affect the gunner’s piece, he will first
set off the deflection change and then apply the deflection
difference.
ig) In the methods described above, it is implied that the
gunner resets the azimuth micrometer with its zero opposite
the micrometer index each time the azimuth-worm knob has
been turned. By so doing, each change in the deflection set-
ting is made by starting with the micrometer index at zero.
This facilitates setting off the tens and units on the azimuth-
micrometer scales. It is important that the gunner before
turning the azimuth-worm knob verify the setting of the
azimuth micrometer to make sure that its zero coincides with
the micrometer index.
ill) Another method is authorized as follows: The zero of
the azimuth micrometer is left opposite the fixed azimuth
index at all times. Deflection changes are made in the proper
direction by turning the micrometer index through the re-
30
SERVICE OF THE PIECE
23
qiiired number of graduations, the only difference being that
the movement of the index does not always start at zero.
(O Irrespective of which method is used, all gunners in a
battery should be required to use the same method.
(3) To lay for direction. — (a) Indirect laying, — ^The deflec-
tion having been set, the gunner brings the vertical ifeir of the
panoramic sight on the aiming point by traversing the piece.
If the amount of movement necessary 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) . No. 2 on the left trail handspike and No. 5 on the
drawbar on the right trail then shift the trails so that the
muzzle moves in the indicated direction until commanded or
signaled to stop by the gunner. The gunner then completes
the laying by bringing the vertical hair of the sight on the
aiming point.
(b) Direct laying on a stationary target, — ^The deflection
having been set, the gunner traverses the piece by means of
the traversing handwheel until the vertical 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 ob-
tained by traversing, the trails must be shifted ((a) above).
(c) Direct laying on a moving target, — See (8) below.
(d) Procedure to insure accuracy, — ^To take up lost mo-
tion, the final movement of the traversing handwheel should
be such as to cause the vertical hair of the sight to approach
the aiming point from the left. The gunner should habitu-
ally rest the weight of his shoulder against the shoulder
guard in laying the piece for direction and keep in this
position until the piece has been fired, to aid in taking up
lost motion. The gunner should habitually lay Vith 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 di-
rection, and No. 1 having called ‘"Set,” the gunner verifies the
laying, moves his head clear of the sight, and calls “Ready”
to indicate that the piece is ready to be fired.
(5) To refer the %nece, — ^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
31
^33-24 SERVICE OP THE PIECE
the piece, the gunner brings the vertical hair of the sight
on the new aiming point (referring point). He then reads
and announces the deflection thus set and records the de-
flection and the referring point upon 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. Fre-
quently 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 gunncr records the deflection set on
his sight upon some convenient part of the carriage or upon
a data board (par. 40).
(7) To measure a deflection. — ^The command is: 1. aiming
POINT (SO AND SO), 2. MEASURE THE DEPTiECTION. 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.
(8) For direct laying on a moving target, to take and
maintain an announced lead. — ^The command is : LEAD
RIGHT (LEFT) (SO MUCH) . The gunner sets his sight at
zero and tracks the target with the traversing handwheel,
keeping the vertical hair of the sight ahead of the target
by the announced lead, measured in the reticule scale of
the sight.
(9) For direct laying on a moving target, to give the
command to fire. — ^In direct lasdng, having heard No. 1
announce *‘Set,” and having the announced lead maintained
on the target, the gunner commands: FIRE.
■ 24. No. 1. — a. Enumeration of duties. — (1) (a) To set the
angle of site.
(b) To level the angle-of-site bubble.
(c) To set the range.
(d) To set the elevation.
(e) To lay for elevation.
(/) To open and close the breech.
(£f) To call “Set.”
Oi) To fire the piece.
it) To use the rammer.
32
SERVICE OF THE PIECE
24
(2) For indirect laying or direct laying on a stationary tar-
get without the gunner^s quadrant, No. 1 performs the duties
prescribed in (1) (a), (b), (c) or (d), (e), (/), (p), and Ui)
above.
(3) For indirect laying with the gunner’s quadrant, No. 1
performs the duties prescribed in (1) (e), (/), (g), and ih)
above.
(4) For direct laying on a moving target, No. 1 perforins
the duties prescribed in (1) (a), (e), (/), (g), and (h) above.
h. Detailed description of certain duties, — (1) To set the
angle of site, — ^No. 1 is first taught to read angles of site on
the angle-of-site scale, and then to set angles of site. To
set an angle of site. No. 1 grasps the angle-of-site worm
knob in his right hand""and turns it until the announced
reading is shown. The angle of site is indicated by a scale
graduated in hundreds of mils from zero to 6, and a microm-
eter scale graduated in mils, 300' being the horizontal. No, 1
first sets the index in the proper section of the scale in hun-
dreds of mils and then sets the units on the micrometer
scale. The last motion in setting the angle of site should be
in the direction of increasing site.
(2) To level the angle-of-site bubble . — ^Having set the an-
nounced angle of site. No. 1 grasps the leveling-worm knob
in his right hand and levels the angle-of-site bubble, making
sure that the last movement of the bubble is from front to
rear.
(3) To set the range. — ^No. 1 is first taught to read ranges
on the range-quadrant range drum, and then to set ranges.
To set a range. No. 1 grasps the range-drum knob in his right
hand and turns it until the announced range is opposite the
index, making sure that the last movement is in the direc-
tion of increasing range.
(4) To set the elevation . — ^The elevation may be set on the
range-quadrant elevation scale. No. 1 is first taught to read
elevations on the elevation scale and then to set elevations.
To set an elevation of zero or above. No. 1 sets the angle of
site at 300 (or at an announced site) and levels the bubble
((1) and (2) above). He then sets the announced elevation
on the elevation scale. The elevation is indicated by a scale
graduated in hundreds of mils from zero to 800 and a mi-
33
24
SERVICE OF THE PIECE
crometer scale graduated from zero to 100 mils. No. 1
grasps the range drum knob in his right hand and turns it
until the announced elevation is shown, making sure that
his last movement is in the direction of increasing elevation.
To set off an elevation of less than zero mils. No. 1 sets the
elevation scale at zero, subtracts the announced negative
elevation from 300, sets the resultant figure on the angle-of-
site scale ((1) above), and centers the angle-of-site bubble
((2) above).
(5) To lay for elevation.-^ia) Without the gunner^s quad'
rant. — ^No. 1, having performed the duties described in (1),
(2) , and (3) or (4) above, grasps the elevating handwheel in
his left hand and matches the range-quadrant pointers, mak-
ing sure that his last movement is ifi the direction in which it
is most difficult to turn the handwheel. (Up to about 400
mils elevation or 7,500 yards range setting, this is in the direc-
tion of decreasing elevation, otherwise in the direction of
increasing elevation.)
(b) With the gunner*s quadrant. — ^See paragraph 22.
(6) To open and close the breech. — (a) To open the
breech. — For the first round. No. 1 cocks the latch by pushing
the plunger in the handle forward; the recoil of the gun auto-
matically cocks the latch for subsequent rounds. No. 1 then
grasps the operating handle with both hands, palms down,
with the fingers fully closed aroimd it, and moves the handle
upward so as to rotate the breechblock as far as it will go.
The movement should be completed with a snap of the fore-
arms and wrists so as to eject the cartridge case fully. As
soon as the breech is open. No, 1 looks through the bore to
see that it is clear. In firing, he opens the breech as the gun
returns to battery. In this operation he must be careful to
close his fingers fully on the operating handle to avoid having
them caught between the breech hoop and the end of the
cradle. Should his fingers be caught in this manner, the tube
must be uncoupled and moved to the rear, and if caught in
such a manner that the breechblock cannot be rotated, the
lug of the safety bolt must be sheared off (TR 1305^75A (now
TR 320-95)).
34
SERVICE OF THE PIECE
24
(b) To close the hreeeh, — No. 1 grasps the operating handle
with his left hand, moves the handle downward, and drops
his hand to his side.
(c) Opening and closing the breech . — ^When No. 1 under-
stands the functioning of the breech mechanism, Nos. 1 and 2
are instructed in loading and unloading the piece. The
breech being open. No. 1 rests his left hand, palm open, lightly
on the operating handle ready to close the breech. As the
round is inserted and pushed home by No. 2, ib causes a slight
rotation of the breechblock which No. 1 immediately takes up
by grasping the operating handle with his left hand and
continues, closing the breech. If No. 1 resists the impulse of
rotation, or starts to close the breech before the round is
fully inserted, the round will rebound and prevent closing the
breech. Whenever this occurs. No. 1, not No. 2, will reseat
the round. For drill purposes in opening and closing the
breech, the drill wedge, a small wooden wedge made locally,
is inserted between the pawl and the plunger lug. The drill
wedge is removed before firing service ammunition. The drill
projectiles used for this instruction 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, receives the ejected round in both
hands.
(7) To call — ^No. 1, when the piece has been loaded,
the breech closed, and the piece laid for elevation, calls ‘‘Set.”
(8) To lire the piece . — ^At the chief of section’s command
NO. <so AND SO) FIRE, or, for direct laying on a moving target,
at the gunner’s command fire. No. 1 grasps the handle of
the lanyard with the left hand, without raising his hand
pulls it to the rear and slightly downward as far as possible,
and quickly releases it. Under no circumstances will No. 1
grasp the lanyard until the gunner calls Ready'' ior *'Fire ") .
If the chief of section gives the command stand clear. No. 1
steps clear of the wheel and, at the command or signal fire,
leans forward, grasps the handle of the lanyard, and fires
the piece. The chief of section may caution, “With the long
lanyard.” In this case No. 1 attaches the long lanyard to the
firing link, steps clear, and fires as previously described.
35
04-25
SERVICE OF THE PIECE
No. 1 detaches the long lanyard immediately after each
round is fired. In case of a misfire, the instructions con-
tained in paragraph 38 will be followed,
(9) To use the rammer, — The spomge and rammer will be
handled by No, 1 only. The rammer is used to extract un-
fired 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 37 will be
followed.
■ 25. No. 2. — a. Enumeration of duties. — (1) To load the
piece.
(2) In volley fire, to call out the number of the round.
(3) When necessary, to assist No. 5 in shifting the trails.
b. Iletailed description of certain duties. — (1) To load the
piece , — To receive the round, No. 2 steps with his left foot
toward No. 4 and grasps the round with his right hand at
the base of the cartridge case and his left hand in rear of
the ogive. He then resumes his position facing the gunner
and inserts the round in the breech, removing his left hand.
He pushes the round home with his right hand. When about
one third of the cartridge case still extends beyond the
breech face, he gives the round a final impetus until his open
hand comes in contact with the breech, and then, continu-
ing the motion, he rotates his hand upward and to the left,
clearing the breech. No, 2 will be particularly careful to
avoid striking the fuze against any portion of the materiel.
To prevent premature bursts caused by projectiles being
struck on the fuze by the piece in recoil, a round to be loaded
will be held well out of the path of the recoil of the gun
until the latter is again in battery. (AR 750-10.)
(2) To 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
36
SERVICE OF THE PIECE
25-26
calls out, “2,800 one; 2,800 two, last round.” He should not
speak louder than necessary to insure his being heard by the
members of his own gun squad.
(3) When necessary, to assist No. 5 in shifting the trails . —
No. 2 goes to the handspike on the left trail, while No. 5
handles the right trail, and shifts the trail right or left as
directed by the gxmner. The command is: MUZZLE RIGHT
(LEFT) , and the trail is shifted in the opposite direction so
that the muzzle is swung in the direction indicated. At the
gunner’s signal, Nos. 2 and 5 lower the trails to the ground.
■ 26. No. 3. — a. Enumeration of duties. — (1) To set the fuze
setter.
(2) To set fuzes.
(3) To fuze shell.
(4) To remove fuzes from shell.
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. Por subscQuent rounds, the cor-
rector is increased (decreased) at the command xtp (down)
(SO MUCH).
(b) No. 3 is first taught to read data set on the fuze setter
and then to set data announced. To set <3ata on the bracket
fuze setter. No. 3 turns the corrector -worm knob with his
right hand until the graduation on the corrector scale, corre-
sponding to the corrector announced, is opposite the index.
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 cor-
rector-worm knob until the graduated line on the corrector
scale, corresponding to the corrector announced, is in coinci-
dence with the index engraved on the rim of the case. He
then turns the knob on the range-scale worm until the grad-
uation on the range scale, corresponding to the range an-
nounced, 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
37
26
SERVICE OF THE PIECE
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 move-
ment of the scales should always be in a counterclockwise
direction.
ig) 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 fuzes. — ^No. 3 sets 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. Tbe
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 at-
tached to the corrector-scale support engages with the fixed
stop pin on the fuze and prevents further motion. When the
fuze has been properly set, the pointer which is attached to
the top of the corrector scale will register with the graduated
line on the closing cap of the fuze. The fuze setter is then
removed.
(3) To fuze shell . — ^At the command shell. No. 3 opens the
fuze box and places it in a convenient position. The projectile
being held by No. 4, No. 3 inserts the designated fuze, being
careful to note that it is fitted with its felt or rubber washer,
and screws it home by hand. The fuze is given its final seat-
ing by the use of the fuze wrench. No great force should be
used. If there is any difficulty in screwing the fuze home, the
fuze should be removed and another inserted. If the same
trouble is encountered with the second fuze, the shell should
be rejected.
38
SERVICE OF THE PIECE 26-27
(4) To remove ju^s from shell, — ^If for any reason a pro-,
jectile which has been fuzed is not to be fired, the fuze will be
removed. The operation of inserting a fuze is reversed. If
the adapter starts to unscrew with the fuze, the unscrewing
must be stopped at once and the shell disposed of as directed
by the executive.
■ 27. No. 4. — a. Enumeration of duties. — (1) To set the fuze
when the bracket fuze setter is used.
(2) To hold the round while No. 3 sets the fuze, when the
hand fuze setter is used.
(3) To hold the round while No. 3 screws the fuze into the
shell.
(4) To pass the round to No. 2.
b. Detailed description of certain duties. — (1) To set the
fuze when the lyracket fuze setter is used. — ^When the com-
mand CORRECTOR (SO MUCH) is given. No. 4 receives a round
of shrapnel from No. 5, 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 movement 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 takes care to hold it firmly against the guide
and to keep the fuze well engaged by a steady pressure on
the base of the cartridge case with his right hand. No. 4
then removes the round by lifting it (iirectly 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 on 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 to any desired time of burning can be reset to iS
(Safe) l?y setting the fuze-setter range ring to S, the cor-
39
27-28
SERVICE OP THE PIECE
rector to normal (30), and resetting the fuze. The fuze
should be inspected 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 per-
cussion is given, No. 4, after removing the waterproof cap,
passes the round directly to No. 2 for loading.
(2) To hold the round while No. 3 sets the jvze, when the
hand fuze setter is used. — ^No. 4 holds the round while No. 3
sets the fuze. No. 4 receives the round from No. 5, removes
the waterproof cap, faces to the right, and partially kneels
on the right knee. He places the base of the cartridge case
on the 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 firmly, pointing upward in the general direction of No.
3's head, while No. 3 sets the fuze.
(3) To hold the round while No. 3 screios the fuze into the
shell . — ^When shell is being used, No. 4 holds the round while
No. 3 screws in the fuze. The round having been removed
from the chest or other container, cleaned, and prepared for
firing, No. 4 removes the fuze plug from the fuze socket and
holds the round firmly on the footboard or other convenient
support, while No. 3 screws in the fuze.
(4) To pass the round to No. 2. — ^No. 4 passes the round to
No. 2 in the most expeditious manner and in such a way that
No. 2 is enabled to graps the base of the cartridge case with
his right hand.
B 28. No. 5. — a. Enumeration of duties. — (1) To remove am-
munition from the chest or other container, to clean and
prepare it for firing, and to pass it to No. 4.
(2) For direct laying on a moving target, to level the
angle-of-site bubble and to set the range.
(3) When necessary, to assist No. 2 in shifting the trails.
(4) To keep empty cartridge cases out of the way.
b. Detailed description of certain duties. — (1) To remove
ammunition from the chest or other container and to clean
and prepare it for firing.-^No. 5, when time permits, ar-
ranges the rounds so that they are within easy reach or
40
SERVICE OF THE PIECE 28-29
partially removes them from their compartments. To re-
move a round from the chest (in units equipped with cais-
sons), No. 5, standing with his left side toward the chest,
grasps the base of the cartridge case with his right hand
and pulls the roimd to the rear, across the front of his body,
grasping the projectile in rear of the ogive with his left
hand at the proper time to prevent the round from falling.
He inspects the projectile to see that it is free from sand and
dirt and that the rotating band is not burred. Any foreign
matter will be removed by wiping with a piece of waste.
Projectiles having burred rotating bands should be placed
aside temporarily until the burrs can be removed with a file.
(2) For direct laying on a inoving target, to level the
angle^ofsite bubble and to set the range. — ^No. 5 takes a
convenient position outside the right wheel, and levels the
angle-of-site bubble and sets the range in the manner pre-
scribed for No. 1 in paragraph 24 b (2) and (3) .
(3) When necessary, to assist No. 2 in shifting the trails . —
No. 5 goes to the drawbar on the right trail, while No. 2
handles the left trail, and gives direction to the piece by
shifting the trails right or left as directed by the gimner.
The command is: MUZZhE RIGHT (liEPT) , and the trail is
shifted in the opposite direction so that the muzzle is swung
in the direction indicated. At the gunner's signal, Nos. 2
and 5 lower the trails to the ground.
(4) To keep empty cartridge cases out of the way. — ^No. 5
throws the cases well to the rear of the left trail 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 accurate lasdng, the gunner and any other cannoneers
who have duties in connection with laying the piece in-
variably will be required to verify the laying after the breech
41
29-31
SERVICE OF THE PIECE
has been closed. When the piece must be established on
uneven ground, it is desirable for accurate firing that the
three points of support, when firing from the jack, be leveled
by pioneer work.
■ 30. Fire at Will. — a. The piece being unlimbered or un-
coupled and prepared 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 so), 2. FIRE
AT WILL. The chief of section repeats this command.
(1) No. 1 lays the gun by eye for elevation so that the
gun is pointed approximately at the target; No. 3 sets cor-
rector 30, range zero; No. 4, if shrapnel is used, sets fuzes
continuously. The gunner keeps the piece laid directly on
his part of the target throughout the firing. Based on his
observation of his shots throughout the firing, No. 1 corrects
the laying for elevation as may be necessary.
(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 firing,
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,
preferably with delay fuze, will be used. In general, the
procedure in firing shell is the same as with shrapnel except
that No. 1 lays so that the shell will strike at or just short
of the base of the target.
■ 31. 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 midpoint between the first stake and the piece, and
is lined in by the gunner so that the vertical hair of his
sight and the two aiming stakes are all in the same vertical
plane. Any lateral displacement of the piece during firing
42
SERVICE OF THE PIECE
31-35
can then be detected easily and corrected for as indicated
in paragraph 32. For night use, the lights should be ad-
justed so that the far one will appear several feet higher
than the near one. The two lights thus will clearly estab-
lish a vertical line- on which the vertical hair of the sight
can be laid.
■ 32. Correction for Lateral Displacement. — ^When the
gunner notes that the piece is out of line with reference to
the aiming stakes, he reports that fact to the chief of sec-
tion. 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 cor-
rection is made as follows: The gimner 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 31.
■ 33. Reporting Errors. — ^Each member of the gun squad
should be constantly impressed with the importance of re-
porting promptly to the chief of section any errors made
by members of the gun squad. The chief of section will
report errors immediately to the executive as prescribed in
paragraph 22b (8).
■ 34. Cease Firing. — ^The command cease firing normally is
given to the gun squad by the chief of section, but in emer-
gencies 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
announcement of the range or elevation.
■ 35. SuspENB Firing. — ^The command suspend firing is
given only when the battery is firing on a prearranged sched-
ule and a temporary halt in the firing is desired. At this
command, firing is stopped, but settings continue to be al-
tered in conformity with the schedule. If the piece is
loaded, the chief of section will report that fact to the execu-
tive. Firing will be resumed at the command resume firing.
43
36-38
SERVICE OP THE PIECE
■ 36. Changes in Data During Firing. — ^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 hot loaded at the announcement
of a new element of firing data, the new data will be set off
and firing resumed at the announcement 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. 37). If no change in the fuze setting is
required or if the piece is loaded with shell, the new data are
set off, and the firing is resumed.
■ 37. To Unload the Piece. — a. When the command un-
load is given. No. 1 opens the breech, and No. 2, standing
at the breech, receives the ejected round with both hands.
In case the extractor fails to eject the round, the rammer
must be used.
b. No. 1 takes the sponge-and-rammer staff and inspects
the rammer head to see that it is thoroughly clean and 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 neces-
sary, taps the rammer staff lightly to dislodge the pro-
jectile. He then pushes the projectile out of the breech
while No. 2, standing at the breech, receives the round in
both hands.
c. To unload a shell fitted with the M-46 or M-47 type
fuze, the special rammer head for handling such fuzes must
be used. When practicable the procedure prescribed in
TR 1370-A should be followed.
■ 38. Misfires. — ^In the event of a misfire, at least three
attempts to fire 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.
■ 39. Ammunition. — a. Ammunition must be protected from
damage, especially to rotating bands and cartridge cases.
44
SERVICE OP THE PIECE 38-4^
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. Fuzes must not be stored with other com-
ponents, and all components should be kept in their water-
proof containers xmtil their early use is anticipated. Pro-
tection should be provided against moisture, dirt, the direct
rays of the sun, and, so 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 ammimition, and suitable dunnage below and
between the layers. Protection against hostile fire may be
obtained by the use of small disi>ersed stacks, trenches, or
dugouts.
b. Care must be exercised to keep sand and dirt out of
the adapter threads of imfuzed ammunition. The fuze
wrench must be used to seat fuzes.
c. With HE shell, Mk. I or Mk. IV, or chemical shell, Mk.
II, the M--46, M-47, Mk. IV, or Mk. V fuzes may be used.
The M-35 fuze may be used with the normal charge.
■ 40. 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,
calibration corrections when appropriate, minimum range
or elevation, data for primary defensive fire missions, and
other data the need for which may be mgent.
■ 41. Firing- Jack Floats. — ^Wooden floats may be prepared
for the firing jack for use in soft and muddy ground, to
prevent the jack from sinking so far into the ground that
the weight of the gun is wholly or partially on the wheels.
Such floats may be devised of timbers and should be at least
2 Y 2 feet long and feet wide.
■ 42. Firing From the Wheels. — ^In an emergency, the piece
may be fired from the wheels, with the trails closed or open^
In this case, the chief of section 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
trails should be opened and the piece raised on the firing
jack.
45
43
SERVICE OF THE PIECE
Section X
CARE AND MAINTENANCE OP MATERIEL
■ 43. General. — a. This section covers such operations in
the care and maintenance of the materiel as may be per-
formed by a battery in the field.
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 1305-75A (now TR 320-95) and SNL C-12.
Operations not covered therein are the function of the
ordnance maintenance company.
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 re-
placement 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-12 by the symbol %. Unless specifically prohibited,
such parts may be installed by 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. The following operations may be performed within the
battery:
(1) Draining and replenishing recoil liquid.
(2) Removal or adjustment of respirator.
(3) Removal of gun from carriage.
(4) Removal, disassembly and replacement of parts of
the breech, operating, and firing mechanisms.
(5) Removal or adjustment of equilibrators.
(6) Dismounting recoil mechanism from the cradle.
(7) Removal, care, and maintenance of wheels and wheel
bearings, including tires.
(8) Maintenance and adjustment of brake mechanism.
(9) Care and maintenance of the firing jack.
(10) Adjustment of the automatic pole support.
(11) Replacement of minor parts or assemblies as listed
in the Standard Nomenclature List, such as the flexible joint
' on the traversing handwheel shaft, traversing and elevating
46
SF.RVICE OF THE PIECE
43-44
stops, drawbar assembly, shoulder guard assembly, screws,
nuts, cottier pins, gear case covers for semiannual cleaning,
etc.
■ 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 compoimd. Powder fouling attracts moisture and has-
tens the formation of rust. At lulls during firing and imme-
diately after firing, the piece must be thoroughly cleaned.
At other times it should be cleaned at intervals not exceed-
ing 2 weeks, depending upon the use and condition. 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 procedure in
cleaning the bore and breech mechanism is described in
paragraph 48 b. 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, — ^Por removing grease. It is
preferred 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 unflnished or non-
hearing steel surfaces only. Issued in five degrees of coarse-
ness, of which 00 is the finest.
(5) Burlap, jute. — ^Issued for cleaning the bore.
(6) Cotton uMste, clean rags, and sponges. — For general
cleaning purposes.
h. A division of duties for members of the gun squad in
routine cleaning and maintenance is as follows:
(1) The gunner — the telescope mount and gunner’s quad-
rant.
(2) Nos. 1 and 2 — ^the breechblock, firing mechanism, and
the bore. No. 1 will clean and, if necessary, oil the range
quadrant.
(3) No. 3 — ^the fuze setter.
(4) Nos. 4 and 5 — ^the elevating and traversing mecha-
nisms and the recoil slides.
47
SERVICE OF THE PIECE
44 ,
4 C3@SLIOES-OUTER EXPOSED PORTION
+ CLEAN & LUBRICATE ENTIRELY
«W+ ©FIRING JACK HOUSING-1 FITTING
4 E ©FIRING JACK SHOT BOLT & RATCHET PLUNGER
U + ©FIRING JACK RACK
4 + ©FIRING JACK HOUSING BOLT
« + ©FIRING JACK RELEASE PLUNGER-1 FITTING
R -F ©ELEVATING ARC-EXPOSED TEETH
+ ©PINTLE PIN - 1 FITTING
« -F ©ELEVATING GEAR CASE-1 FITTING
•w + ©TRAIL HINGE PIN-1 FITTING
m\ + ©BRAKE CAM ROLLERS- SPARINGLY t FITTING
4 + ©BRAKE ROD PINS (2)
©WHEEL HUB
4 O ©TRAIL LOCK PIN
4 -f ©ELEVATING HAND WHEEL HANDLE
■W -F ©ELEVATING HANDWHEEL GEAR CASE-1 FITTING
4 + ©STAFF SUPPORT PINS
« -F © RANGE QUADRANT - 4 FITTINGS
<5X#@ TRUNNION BEARING
4 + ©TRAIL HOOK HANDLE PINS
« + ©DRAWBAR END BEARING-1 FITTING
« + ©DRAWBAR BEARlNG-2 FITTINGS
R E® BREECH & FIRING MECHANISMS
WHEN APPLIED
CD DAILY DURING CONSTANT USE.OTHERWISE EVERY TWO WEEKS,
+ EVERY TWO WEEKS
• EVERY SIX MONTHS
NOTE -Before firir^g ond during lulls, clean and oil beoring surfocesof
breech ond firing mechanisms, ond slides. After firing, clean and
lubricofe bore, breech and firing mechanisms, slides, and all other exposed
ond unpointed surfaces. Wheel bearings should be repacked offer
immersion in wafer.
this chart applies also to the M2A2 gun.
75-mm gun, M2.
49
44-47
SERVICE OF THE PIECE
(5) Higher-numbered cannoneers assist in the operations
as directed by the chief of section.
■ 45. Lubrication. — a. Caisson and limber wheel bearings
require Vs pint of lubricating oil daily, or every 25 miles.
The oil is applied by means of the oiler at the valve in the
center of the hub cap without removing the wheel. The
automatic pole support on the limber should be packed with
mineral lubricating grease at each disassembly. All other
parts on these vehicles should be oiled with lubricating oil
weekly.
b. To facilitate identification, all oil holes and grease
fittings should be made conspicuous by circling with bright
red enamel.
c. Lubrication instructions for the gun and carriage are
covered in figure 6.
■ 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 white-
wash made from either. After 2 to 6 hours the lime is
washed off and the materiel rinsed thoroughly with water.
When large quantities of water are available, warm (but
not boiling) water should be used instead of whitewash. In
all cleaning operations, the gas mask and special gasproof
gloves must be worn. All cleaning rags, sticks, etc. are dis-
posed by burying. They must not be burned as the heat
will disseminate dangerous vapor.
■ 47. Recoil Mechanism. — a. General . — Battery mainte-
nance of the recoil mechanism is limited to exterior clean-
ing and lubricating, draining and filling with recoil oil, ad-
justment of the respirator, and disconnection of the piston
rod from the coupler. Only the heavy low-pour-point recoil
oil as issued by the Ordnance Department may be used in
the recoil mechanism. A full reserve of oil for the recoil
50
SERVICE OP THE PIECE
47
system amounts to approximately one half the contents of
the screw filler. In using the screw filler, care must be
exercised to prevent crossing the threads. 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 rear face of the counterrecoil-cylinder rear
sealing plate at the rear of the cradle, as follows:
(1) No reserve, — ^Th© indicator is at the bottom of the
recess. The piece must not be fired in this condition.
(2) Full reserve . — ^The end of the indicator is even with
the rear face of the sealing plate.
(3) Excess reserve . — ^The indicator projects beyond the
rear face of the sealing plate. The piece must not be fired
in this condition.
h. Operation prior to traveling . — ^In order to hold the gun
firmly in battery during travel, excess reserve oil should be
added to the recoil system until the index shows excess oil
reserve and stops moving to the rear. This requires about
one screw filler of oil for filling from a no-reserve status,
c. Operations prior to firing . — (1) Before firing, the re-
serve oil should be extracted until an insufficient reserve is
indicated, then a full reserve should be established by insert-
ing oil until the index is flush with the rear face of the rear
sealing plate.
(2) The respirator should be removed in order to clean the
front interior of the recoil cylinder and to inspect for excess
oil leakage.
(3) The front 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 at any
of these places is not important, but if there is an imdue
leakage the piece must not be fired, and the condition should
be reported to the Ordnance Department.
d. Operations during firing . — (1) During firing, the recoil
mechanism should be maintained at full reserve, the respira-
tor kept properly adjusted, and the slides kept clean and
properly lubricated.
(2) The chief of section constantly verifies the complete
return of the piece to battery. Firing may be continued
as long as the cradle index (at right rear of breech hoop and
51
47-^8
SERVICE OF THE PIECE
cradle) remains between the two reference marks on the
breech hoop.
(3) The chief of section constantly observes the behavior
of the recoil mechanism in firing, and takes such action in
the case of malfimctioning as is indicated below:
Malfunction
Cause
Correction
Oil index not func-
tioning.
Index stuck or sluggish
because of paint, dirt, or
overtight packing.
Withdraw all reserve oil, then
insert approximately one-half the
capacity of the oil screw filler.
Tap the oil index lightly as oil is
being added. If it still fails to
function notify the ordnance
maintenance company. (In an
emergency, after bleeding and
refilling, the piece may be fired
imtil the gun returns into battery
with a shock, when reserve oil
should be extracted, or the gun
fails to return to battery, when
additional oil should be inserted .)
Failure of gun to
return to battery.
(1) Insufficient oil re-
serve.
(2) Dirt or obstruction
on the slides, damaged
slides, damaged piston
rod or piston, excessive in-
ternal friction or low nitro-
gen pressure.
(1) Insert sufficient fresh oil to
bring the index even with the
rear face of the rear sealing plate.
(2) Clean and lubricate the
1 slides. If this fails to correct the
trouble, send recoil mechanism
to the ordnance maintenance
company for repair.
Return of gun to
battery with a shock.
(1) Air from recoil cylin-
der escaping too fast
through respirator.
(2) Too much reserve
oil.
(1) Adjust respirator to give
smaller air-vent setting.
(2) Withdraw reserve oil until
the index indicates an insufficient
reserve, then insert sufficient oil
to bring the index even with the
rear face of the rear sealing plate.
■ 48. Barrel Assembly, Breech Mechanism, and Firing
Mechanism. — a. Operations during firing . — (1) During firing,
all exposed bearing surfaces must be kept clean and covered
with a thin film of lubricating oil.
(2) Whenever the rate of firing permits, the bore should
be swabbed with clean water and a sponge.
(3) The causes and corrections of malfunctioning of the
breech and firing mechanism are given in the following
table:
52
SERVICE OF THE PIECE
48
Malfunction
Cause
Correction
No momentum to
swing of firing hammer.
Broken firing-rack
spring.
Keplace spring.
Failure to discharge
when proper percussion
on primer is obtained
(misfire).
Defective primer.
See paragraph 38.
Failure to discharge
until after several per-
cussions on primer
(primer stuck weakly).
(1) Firing rack and
hammer not working
freely.
i
(2) Weak firing-rack
spring.
(3) Deformed firing-
pin point.
(4) Friction on lan-
yard.
(1) Disassemble ’ firing mech-
anism and examine all parts for
burs or roughened bearing sur-
faces. Remove burs or rough
spots with crocus cloth or oil-
stone. Clean off dirt and gum-
my oil with cleaning solvent.
Dry and coat with lubricating
oil.
(2) Replace spring.
(3) Replace firing pin.
(4) Allow less slack when firing
with a long lanyard.
Failure to discharge;
,no percussion on primer.
(1) Safety piece not in
firing position.
(2) Breechblock not
fully closed.
(3) Broken firing
pin.
(1) Set safety piece plunger in
the hole marked “Fire'^ or “Tir.”
(2) Close breechblock.
(3) Replace firing pin.
Failure to extract cart-
ridge case.
Broken extractor.
See paragraph 37. Examine
the edge of the chamber, for burs
or deformation. Replace extrac-
tor.
Pawl fails to operate.
Broken pawl spring
or broken breechblock
latch spring.
If latch spring is broken, re-
place it. If pawl spring is bro-
ken, replace breechblock latch
assembly.
Breechblock does not
rotate freely.
(1) Lack of lubrica-
tion.
(2) Burs or rough-
ening of threads of
breechblock or breech
recess.
(1) Remove block, clean recess
and threads with solvent, wipe
dry; coat lightly with lubricating
oil; reassemble.
(2) Remove and clean as in (1)
above. If burs or roughness are
found, the correction must be
made by ordnance maintenance
company.
Safety bolt does not
remain in upper posi-
tion when coupler key
is withdrawn.
Weak" or broken
safety-bolt spring, or
spring does not engage
in notch.
Replace safety-bolt assembly.
If notch is deformed refer to ord-
I nance maintenance company for
1 correction.
Safety bolt fails to rise
when coupler key is
withdrawn.
Safety-bolt lug is
shorn off.
Replace safety-bolt assembly.
Note. — The safety bolt cannot
rise when the breechblock is
closed; forcing out the coupler
key with the breech closed results
in shearing off the lug.
53
48-49
SERVICE OP THE PIECE
&. Operations after firing. — (1) As soon as possible after
firing, the breechblock and firing mechanism should be dis-
assembled, the gun retracted on its slides, and all parts
cleaned and lightly oiled.
(2) In disassembling the breech mechanism, the breech-
block must be in the closed position before the extractor
tang is disengaged from the extractor spindle. If the tang
is disengaged with the block open, it may drop into the cam
groove and jam the block.
(3) In order to retract the gun for cleaning the slides,
the piston rod must be disconnected from the coupler. To
do this the breechblock must be open or previously removed,
and the cradle level.
(4) The bore, breech mechanism, and firing mechanism
are washed with a solution of Vz pound of soda ash or 1
pound of sal soda in 1 gallon of water. Cleaning the bore
is accomplished 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 bore should be swabbed with clear
water and then wiped dry. Finally, it should be lightly
coated with lubricating oil, either light or heavy depending
on the weather. The process may have to be repeated on
successive 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 oil.
■ 49. Cleaning Slides. — a. The bronze slides should be ex-
amined by retracting the gun until three fourths of the
slides are exposed. Burs or rough spots are removed with
a fine file. The slides should be cleaned with dry-cleaning
solvent, wiped dry, and coated with a light film of lubricating
oil. To retract the gun, lay the piece at zero elevation, open
the breech, raise the piston coupler key latch, withdraw
the key from right to left as far as it will go, and push the
tube to the rear. The gun is placed in battery by reversing
this procedure.
&. Periodically, or every 2 weeks when in constant service,
the gun should be removed from the carriage in order to
clean the entire length of the slides. The gun is removed
as follows:
54
SERVICE OF THE PIECE
49-50
(1) Provide at least three heavy timbers to support the
gun in a horizontal position when it is being removed.
(2) Set the brakes with the carriage in the firing position.
(3) Depress the gun and screw the equilibrator assembling
nuts their full length on the equilibrator rods.
(4) Elevate the gun to zero.
(5) Open the breech, raise the piston coupler key latch,
and withdraw the key from right to left as far as it will go.
(6) Push the gun to the rear, pairs of men at opposite
ends of the timbers supporting the gun at either end and
at the center. Place the gun on wooden blocks or a suitable
rest to prevent damage to the slides.
c. To replace the gun, the procedure in b above is reversed.
■ 50. Dismounting Recoil Mechanism From Carriage and
Care of Trunnion Bearings. — a. At least once every 6
months the cradle should be removed, and the trunnion
bearings should be cleaned with dry-cleaning solvent, dried,
and packed with medium mineral lubricating grease. The
recoil mechanism holding cradle and the recoil mechanism
are considered a unit and as such may not be disassembled.
When an ordnance maintenance company is readily avail-
able, it is advisable that the removal of the recoil mechanism
and packing of the trunnion bearings be accomplished by
that unit.
b. To dismount the recoil mechanism from the carriage
the procedure is as follows:
(1) Remove the telescope mount and range quadrant.
(2) Remove the gun from the carriage as described in
paragraph 49 b.
(3) Loosen the trunnion nut screws and remove the nuts.
(4) Remove the screws in the outer trunnion ball retainers.
(5) Unscrew the trunnion cap bolts and remove the caps.
(6) Raise the recoil mechanism holding cradle and the
recoil mechanism slightly, and carefully remove from each
of the holding-cradle trunnions the outer trunnion ball
retainer, outer .bearing plate, cup, ball, inner bearing plate,
and spacer.
(7) Lift the holding cradle with recoil mechanism clear
of the top carriage trunnion bearings and place on wooden
blocks.
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50-52
SERVICE OF THE PIECE
c. The recoil mechanism is mounted on the carriage by
reversing the procedure detailed in b above.
■ 51. EQtHLiBRATORS. — a. The battery is prohibited from per-
forming any operations other than the removal or the ad-
justment of the eauilibrators. The adjustment and routine
cleaning and lubricating of the eauilibrators are accom-
plished without removing the assembly from the carriage.
b. The following procedure is used to adjust an equilibra-
tor:
(1) Place the carriage in the firing position.
(2) Depress the gun until the equilibrator assembly nut
can be assembled its full length on the equilibrator rod.
(3) Elevate the gun until the’ equilibrator trunnion pin
is clear of the bearing in the top carriage.
(4) 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.
(5) After the adjustment is completed, reengage the lock,
lower the cradle to seat the eqxiilibrator trunnion pin, and
remove the assembling nut.
c. An equilibrator is removed from the carriage by follow-
ing the procedure outlined in h above except that the equi-
librator trunnion pin is removed from the equilibrator
assembly during operation (4).
■ 52. Wheels and Wheel Bearings. — a. The care and main-
tenance of the wheel mechanism including tires is a func-
tion of the battery. Tire pressure should be maintained 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 fiushed out, new grease pressed into the space
between the cleaned and dried rollers and race by hand, and
the wheel bearings adjusted.
b. To disassemble the wheel hub from the spindle the
procedure is as follows:
(1) Remove the hub cap.
(2) Remove the cotter pin, slotted nut, and washer from
the spindle.
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SERVICE OP THE PIECE
52-54
(3) Pull the hub from the spindle, being careful to pre-
vent the roller bearing from falling to the ground.
c. To assemble the wheel hub on the spindle the procedure
is as follows:
(1) Clean and dry the bearings and pack with fiber wheel
bearing grease. See that the inner bearing is properly in
place.
(2) Pack fresh grease in the cavity of the hub.
(3) Slide the wheel hub over the spindle, guiding the
cup of the inner roller bearing over the cone and rollers,
and the brake drum over the brake shoes,
(4) Slide the outer cone and roller on the spindle and
press it firmly into its seat in the hub.
(5) Install the washer and nut, tightening the latter suffi-
ciently to allow the wheel to revolve freely and without end
play.
(6) Test the bearing adjustment by placing a short bar
between the 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. Insert cotter pin and attach the
hub cap.
■ 53. Brake Mechanism. — ^Brake adjustment is accomplished
by rotating the adjusting wedge. Wheel bearings should
be checked for proper adjustment and the brake mecha-
nism lubricated prior to brake adjusting. The procedure
for adjustment is as follows:
a. Set brake lever at full released position.
h. Jack up the wheel.
c. Adjust until a drag is felt on the wheel. Then back
off just enough so the brake does not drag. Brakes must
be cold.
d. The position of the hand lever is adjusted by adjusting
the length of the brake rod.
■ 54. Firing Jack. — a. To prevent the burring of the ele-
vating gears when the gun is dropped from the jack, it
should be so elevated that the gun wheels are only about
2 inches from the ground. To avoid running off the rack.
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54-56
SERVICE OF THE PIECE
the jack should not be elevated beyond the height at which
a red mark on the rack appears.
b. As soon as practicable after the first few rounds are
fired in a position. No. 2 will release the firing jack, lower-
ing the piece to its wheels, reset the jack, and again raise
the jack, to ease lateral strain on the jack caused by the
settling of the piece during the first few rounds.
c. The firing jack should be cleaned and lubricated at
least every 2 weeks. During the cleaning, parts should be
examined for imdue wear and the ratchet plunger spring
examined for a possible permanent set, which may result
in a slippage of the jack.
■ 55. Automatic Pole Support on the M1918 Limber. — The
disassembly and adjustment of the automatic pole support
are described in TR 1305-A. It must be adjusted to hold
the pole assembly at a height of 29 inches without support
from the harness, the carriage being limbered and loaded.
Malfunctioning may be caused by lack of lubrication, the
pole being loose in the pole socket, the support spring not
being in proper adjustment, and by a worn pintle lug or
lunette. To adjust the support it must be disassembled and
the spring tightened sufficiently to support a 20 -pound weight
suspended from the pole assembly at the neck-yoke stop.
If the pintle lug and the lunette are worn, shims must be
placed under the pintle adjusting bolt.
■ 56. Caisson Band Brake. — ^The brake mechanism is de-
scribed in TR 1305-A. No dressing of any kind may be
placed on the brake linings. Brake bands may slip if the
linings are worn or greasy. If greasy, they should be washed
with solvent and adjusted. If the lining is badly worn it
must be replaced by the ordnance maintenance company.
Brakes must be adjusted to give equal action on the wheels.
To adjust a brake, jack up the wheel, disconnect the ad-
justing nut, and tighten the link. When the brake is in the
“on*' position, the wheel should not turn when a man stands
on the outer end of a horizontal spoke. When in the
position the brake should not drag. In adjusting, allowance
should be made for subsequent wear of the lining; initially,
the lever should not come into the last notch when “on."
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SERVICE OP THE PIECE
57
■ 57. SiGHTiKG AND PiRE-CoNTROL EQUIPMENT. — tt. General , —
Especial care is required to insure the positive and accurate
functioning of the sighting and fire-control mechanism.
Care must be exercised to prevent denting the soft metal
surfaces or scratching the glasses. Dirt should be removed
from optical surfaces by brushing lightly with a earners hair
brush. Oil or grease should be removed from glass by ap-
plying alcohol or, if alcohol is not available, by breathing on
the glass and then wiping lightly with lens paper or a clean,
soft cloth. The 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
I, 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
gun the sight displacement is 14.5 inches to the left of and
II. 375 inches higher than the axis of the bore. Aiming
stakes with wooden blocks or markers attached make a
suitable test target. In direction tests these 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.
c. Telescope mount. Ml 5, panoramic telescope, MS, and
range quadrant. Ml . — ^Battery personnel are forbidden to
disassemble any part of the telescope, telescope mount, or
range quadrant, but are permitted to perform certain adjust-
59
57 SERVICE OF THE PIECE
ments. The following procedure may be used to insure
accuracy of the sighting and laying mechanism:
(1) Panoramic telescope and telescope mount assembly . —
(a) Level the carriage trunnions and 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
alinement.
(c) Set all scales and micrometers at zero and level the
bubbles.
id) Look through the telescope. If the intersection of
the cross hairs is on the appropriate part of the target the
adjusment is correct. If not, make tests and adjustment of
individual parts as explained in (2) to (6) below.
(2) Longitudinal level of the telescope mount. — ia) Center
the cross-level bubble.
ib) Place a test level on the top surface of the telescope
socket, parallel to the bore, and center the test bubble by
means of the longitudinal-leveling knob.
(c) Note the position of the longitudinal -level bubble of
the mount. If it is not centered within three divisions, cor-
rect the level vial by removing the plug from the end of
the vial and adjusting by means of the four set screws.
(3) Cross level of the telescope mount. — (a) Center the
cross-level bubble.
ib) Place the test level on top of the telescope socket,
with its axis parallel to the axis of the cradle trunnions,
and center the test bubble by means of the cross-leveling
knob.
ic) Note the position of the cross-level bubble of the
mount. If it is not centered within one division, adjust the
level vial as in (2) (c) above.
(4) Lost motion in cross^level device. — To take up lost
motion, loosen the screw which locks the nut and adjust.
Reset the screw.
(5) Panoramic telescope for direction. — ^If the vertical cross
hair of the telescope is not on the bore-sighted target with
zero settings, put it on by loosening the two headless screws
on the telescope socket, and then adjust the two headless
pivot screws. Tighten the locking screws.
60
SERVICE OF THE PIECE
57
(6) Panoramic telescope for elevation. — ^If the horizontal
cross hair of the telescope is not on the target with zero
settings, put it on by turning the elevation knob of the
telescope. Then loosen set screw on the knob and slip the
knob around until the zero graduation registers opposite the
index, being careful not to disturb the cross hair.
(7) Range quadrant. — (a) Lay the tube horizontal, using
the gunner’s quadrant.
(b) With the site bubble centered, site scales set at 300,
and range and elevation scales set at zero, the movable in-
dexes should be in coincidence. If not, adjust indexes and
micrometers as indicated in (8) to (10) below, without
adjusting the level vial.
(8) Range quadrant for elevation. — (a) Turn the eleva-
tion micrometer knob until the elevation index is opposite
zero on the elevation scale, and note the position of the zero
on the micrometer with respect to its index. If not In
agreement, loosen the three screws in the end of the mi-
crometer knob, hold the knob, and slip the micrometer until
its zero graduation and the index are in agreement.
(b) This adjustment may also be accomplished by setting
the zero on the micrometer opposite its index and then
loosening the index screw and bringing the elevation scale
index opposite its zero graduation.
(9) Range quadrant for angle of site. — ^Turn the angle-
of-site micrometer knob until the angle -of -site index is op-
posite the 3 graduation and note the position of the zero on
the angle -of -site micrometer with respect to its index. If
not in agreement, loosen the nut in the end of the microme-
ter knob, hold the knob, and slip the micrometer until the
zero graduation and the index are in agreement. Tighten
the nut.
(10) Indicating and designating indexes of the range
quadrant. — ^Turn the longitudinal leveling knob until the
angle -of -site bubble is centered. Loosen the securing screws
and move the gun elevation index and elevating worm wheel
segment index until they coincide. Tighten securing screws.
d. Gunner's quadrant. — ^To test the gunner’s quadrant, set
the scales at zero, place it on the leveling plates of the piece,
and level the quadrant bubble. Then reverse the quadrant
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57
SERVICE OP THE PIECE
on its seat. The bubble should center itself. If it does not,
it should be adjusted at the earliest opportunity by the
Ordnance Department, If it must be used, apply a correc-
tion in the appropriate sense equal to one half of the meas-
ured error determined in the end-for-end test.
c. Bracket jvze setter, M1916. — (1) To eliminate looseness
in either worm gear, loosen the set screw, and with a teat
wrench turn the adjusting plug clockwise. Retighten the
set screw. The range crank should not fall of 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
62