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FM 6-50
FIELD ARTILLERY
FIELD MANUAL
SERVICE OF THE PIECE
75-MM GUN, M1897 AND M1897A4,
HORSE-DRAWN AND TRUCK-DRAWN
Prepared under direction of the
Chief of Field Artillery
UNITED STATES
GOVERNMENT PRINTING OFFICE
WASHINGTON : 1939
For sale by the Superintendent of Documents, Washington, D. C. - Price 15 cents
WAR DEPARTMENT,
Washington, October 1, 1939.
FM 6-50, Field Artillery Field Manual, Service of the Piece —
75 -mm Gun, M^697 and M1897A4, Horse-drawn and Truck-
drawn, is published for the information and guidance of all
concerned.
[A. G. 062.11 (6-17-39) .]
By order of the Secretary of War:
G. C. MARSHALL,
Chief of Staff.
Official:
E. S. ADAMS,
Major General ,
The Adjutant General.
(ii)
TABLE OP CONTENTS
Section I. General: Paragraph Page
Purpose and scope 1 1
References 2 1
Definitions and terms 3 1
Section II. Organization:
Composition 4 2
Formation 5 3
Section 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
Section IV. Movements of the carriages by hand:
Limbered or coupled 12 7
Unlimber eel or uncoupled 13 7
Section V. Unlimbering and limbering:
Unlimbering 14 8
Limbering 15 12
Section VI. Uncoupling and coupling:
Uncoupling 16 13
Coupling 17 14
Section VII. Preparation for action and march
order, horse-drawn units:
To prepare for action 18 14
Posts of the cannoneers, carriages unlimbered. _ 19 16
March order 20 17
Section VIII. Preparation for action and march
order, truck -drawn units:
To prepare for action 21 19
Posts of the cannoneers, pieces uncoupled 22 21
March order 23 21
Section IX. Duties in firing:
General 24 23
Chief of section 25 24
Gunner 26 28
No. 1 27 34
No. 2 28 36
No. 3 29 37
No. 4 30 39
No. 5 31 41
Section X. Additional information on the service of
the piece:
Use of the sight lines, collimator sight 32 41
Use of the sight extension bar 33 42
Accuracy in laying 34 42
To raise and lower the brake, 75-mm gun,
M1897, horse-drawn 35 42
(in)
TABLE OF CONTENTS
Section X — Continued. Paragraph page
Fire at will 36 43
To fire by individual sections with direct lay-
ing at moving targets 37 43
Aiming stakes 38 45
Correction tor lateral displacement 39 45
Trail logs and platforms 40 45
Reporting errors - 41 46
Cease firing ‘ 42 46
Suspend firing 43 46
Changes in. data during firing 44 46
To unload the piece 45 46
Misfires 46 47
Ammunition 47 47
The section data hoard 48 48
Section XI. Care and maintenance of materiel:
General 49 48
Cleaning 50 49
Lubrication 51 50
Protection against chemicals 52 50
Recoil mechanism 53 51
Barrel assembly, breech mechanism, and firing
mechanism 54 57
Miscellaneous parts of carriages 55 59
Sighting equipment 56 61
FM 6-50
FIELD ARTILLERY FIELD MANUAL
SERVICE OF THE PIECE
75-MM GUN, Ml 897 AND M1897A4, HORSMRAWN
AND TRUCK-DRAWN
(The matter contained In this manual supersedes TR 430-15,
November 1, 1932, and TR 430-16, June 28, 1934.)
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.
B 2. References. — a . Description , operation, functioning ,
and care of materiel. — (1) TR 1305- A; SNL C-5.
(2) TR 1305-75 A (now TR 320-95) ; SNL C-4; SNL C-25.
b. Description and operation of fire-control and sighting
equipment . — TR 1320-0 (now TR 310-20); SNL P-11;
SNL P-28,
C. Ammunition . — TR 1355-75A; TR 1370-A; SNL Rr-1;
SNL R — 3.
d . Cleaning and preserving materials . — TR 1395-A; SNL
K— 1.
e. The field artillery driver . — Part Two, PM 6-5.
/. Maneuvers of the battery . — Part Two, PM 6-5.
g. Safety precautions in firing, — AR 750-10; chapter 4,
FM 6-40.
h. The firing battery . — Chapter 1, PM 6-40.
i . Gunnery. — PM 6-40.
j. Reconnaissance, occupation, and organization of posi-
tion. — Part One, PM 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
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SERVICE OP THE PIECE
used to designate a section of the firing battery, in this
restricted sense, a gun section is composed of one piece and
the additional materiel and the personnel required to serve
that piece.
b. Limbered. — A piece (caisson) is said to be limbered
when its lunette is attached to the pintle of its Umber.
c. U nlimbered. — A 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 (left) The direction right (left) is the right
(left) of one facing to the front.
h. In battery. — The term “in battery” is used to designate
the position of the gun when it is in its normal firing
position .
Section n
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 assigned 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 con-
sists of an ammunition corporal and cannoneers as pre-
scribed in Tables of Organization. These cannoneers are
numbered consecutively, beginning with No. l t and are as-
signed to the ammunition vehicles of the ammunition (fifth)
section. In organizations equipped with caissons, the can-
noneers are equally divided between the two caisson s, the
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SERVICE OF THE PIECE 4-6
lower- numbered cannoneers being assigned to the first
caisson.
(2) Posts and movements prescribed hereinafter for the
gun squad apply, with obvious modifications, to an ammuni-
tion squad.
H 5. Formation. — a . Order of formation . — A gun squad is
formed as shown in figure 1.
| a | 4 | a | a | t |b )
Figure 1. — Formation of the gun squad.
Higher-numbered cannoneers, if present, form in order on
the left of No. 5.
b. To form. — (1) The place of formation is indicated and
the command given thus, for example: 1. in front (rear) of
YOUR PIECES (CAISSONS), Or 1. ON THE ROAD FACING THE PARK,
2. PALL 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-
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
cannoneer 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.
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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.
b. 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 Gtjn Squads. — The squads having been
marched to the vicinity of the carriages are posted at the
command squads in front (rear) of your piece (caissons).
Each gunner marches his squad to its carriages and posts it
in the position indicated,
■ 8. Posts of 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 paragraphs 19
and 22.
■ 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 can-
noneers are then sent to their posts by the foregoing com-
mand, 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 ate
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,
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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 can-
noneers, if present, mount as prescribed by the chief of
section.
(2) Truck-drawn batteries . — At the first command, the
cannoneers move at the double time to positions on the
ground convenient for mounting the truck. At the second
command, all mount as prescribed by the battery com-
mander.
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-dravm batteries . — At the first command, the
cannoneers assume positions from which they can dismount
promptly; at the second command, they jump to the ground
and take their posts at the double time.
b. If the command is: 1. cannoneers, 2. DISMOUNT, the
cannoneers execute, at the command dismount, all that has
been prescribed for the commands cannoneers, prepare to
dismount and dismount,
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SERVICE OF THE PIECE
12-13
Section XV
MOVEMENTS OP THE CARRIAGES BY HAND
■ 12. Limbered or Coupled. — a. Horse-drawn 'batteries . — (1)
To the front. — The command is: 1. pieces (caissons) forward,
2. MARCH, 3. HALT. In each squad at the first command
the gunner and No. 1 hasten to the end of the pole; Nos. 2
and 5 to the limber wheels; Nos. 3 and 4 to the piece (caisson)
wheels; higher- numbered cannoneers, if present, to posts as
directed by the chief of section; the gunner and the even
numbers working on the right side of the carriage, odd num-
bers 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 command march,
all assist in moving the carriage to the front. At the com-
mand halt, the carriage is stopped. In the case of the piece,
No. 3 sets the brake. In the case of the caisson, Nos. 3 and 4
lower the caisson prop and No. 4 sets the brake. All can-
noneers 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. Truck -draum 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. — (a) Borse-drwum batter-
ies. — At the first command, Nos. 3 and 4 grasp the trail han-
dles, No. 3 on the light, No. 4 on the left; No. 2 grasps the
left wheel and No. 5 the right wheel; the gunner and No. 1
place themselves so as to work advantageously at the breech
of the piece in moving forward, at the’ muzzle in moving
backward; higher-numbered cannoneers, if present, are
employed as directed by the chief of section.
(b) Truck-drawn batteries. — At the first command, No. 2
places the trail handspike, for those carriages thus equipped,
in the firing position if it is not already there; Nos. 2 and
3 grasp the trail handles. No, 3 on the right, No. 2 on the
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SERVICE OF THE PIECE
left; No. 5 grasps the trail handspike for those carriages thus
equipped; the gunner places himself where he can operate
the brakes; No. 1 places himself on the right of the breech.
No. 4 at the muzzle; higher- numbered cannoneers, 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. In truck-drawn batteries,
when moving up or down 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, in truck-
drawn batteries the gunner sets the brake, and all resume
their posts (pars. 19 and 22) .
b. Caisson . — Executed as explained for the piece, except
that No. 4 releases the caisson brake and No. 3, when the
trail is raised, raises and secures the caisson prop. The gun-
ner 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
intended to fire to the front, the caisson should be placed
on the left of the piece before the command for unlimbering
is given; if it is intended to fire to the rear, the caisson should
be on the right of the piece; if to the flank, on either side
of the piece. In emergencies the carriages may be un-
limbered from any formation.
(2) After unlimbering. — (a) The adjacent wheels of the
piece and the caisson are about 1 foot apart, trails of the
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SERVICE OP THE PIECE 14
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) The Interval of 1 foot may be increased to permit
wide movements of the trail if they are expected, but efforts
should be made to preserve to the fullest extent possible the
protection afforded by the shields.
(d) In emergencies the caisson may be placed temporarily
oh 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.
(e) 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
designated by the battery commander, where they are dis-
posed so as to take the best advantage of cover and conceal-
ment. If no cover and concealment are available, they are
located in rear of either flank, faced toward the front, with
wide intervals between them.
b^To unlimber. — (1) General . — In unlimbering to fire to
the front or rear, the caisson establishes the position; in
unlimbering to fire to the flank, the element (piece 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 pre-
scribed in paragraph 13, in the order designated by the chief
of section. If the teams are not hitched, the carriages are
unlimbered successively, the one which establishes the posi-
tion being unlimbered first. Limbers are moved to their
position by cannoneers designated by the chief of section.
(2) To fire to the front . — The carriages being in double
section, the caisson on the left, the command is: ACTION
FRONT. If marching, the carriages halt at the command
or signal. 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
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SERVICE OF THE PIECE
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.
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). The gunner and No. 1 lower the trail to the
ground, and all the cannoneers at the piece take their posts
(pars. 18c and 19).
(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 end 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
section, 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.
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SERVICE or THE PIECE
14
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). The gunner and No. 1
lower the trail to the ground, and the cannoneers at the
piece take their posts (pars. 18c and 19). Higher-num-
bered cannoneers, when present, assist in the movement as
directed by the chief of section.
(c) Limbers . — At the command or signal drive on, the
limbers take their prescribed positions. To take post in
rear of the carriages, the caisson limber inclines well to the
right, 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
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 flank. — (a) The carriages being in
double section, the caisson on either side of the piece, the
command 1st ACTION RIGHT (LEFT). The movement is
executed according to the principles of action front and
action rear, with the following modifications: After the car-
riages are unlimbered, the muzzle of the piece is turned in
the direction of fire and the trail of the caisson in the oppo-
site 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
tlieir prescribed positions. To take post in rear of the car-
riages, the limber away from the fiank toward which fire is
to be delivered moves out first, wheels away from the direc-
tion of fire, and after having gained sufficient distance to
the rear executes an about, and halts so that the heads of
the lead horses (or the end of the pole if teams are not
hitched) will be 25 yards from the rear of its carriage. The
other limber follows and takes post in a similar manner.
11
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SERVICE OF THE PIECE
■ 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 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 and No. 1 face to the rear at their posts; No. 2 places
himself on the right of the gunner and faces to the rear;
No. 5 places himself on the left of No. 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,
FM 6-5. As soon as the limber has halted in prolongation
of the trail, the gunner and No, 1 spring to the trail handles
and raise the trail. Nos. 2 and 5 hasten to the piece wheels
and prepare to assist in any movement of the carriage that
may be necessary. The gunner and No, 1 place the lunette
over the pintle; the gunner then latches the pintle. The
caisson is limbered simultaneously in the same manner; Nos.
3 and 4 handle the trail. No. 4 latching the pintle. Higher-
numbered cannoneers assist by working at the wheels of the
caisson in any movement of the carriage. As soon as the
carriages are limbered, cannoneers take their posts at the
carriages limbered (fig. 2) ,
b. To limber rear . — The carriages being in position and
in march order (par. 20), the command is: LIMBER REAR.
(1) No. 4 releases the caisson brake; Nos. 3 and 4 raise and
secure the caisson prop. All cannoneers working 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 limber-
ing (a (1) above),
12
SERVICE OP THE PIECE
15-16
(2) The limbers are brought up and the limbering is
completed as prescribed in a (2) above.
SECTION VI
UNCOUPLING AND COUPLING
■ 16. Uncoupling. — a. General . — At drills, trucks are posted
as directed by the battery commander. In active service and
in instruction simulating it, the trucks are conducted by the
first sergeant to a place previously designated by the battery
commander, where they are disposed so as to take the best
advantage of cover and concealment. If no cover and 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. 3 hastens to the muzzle.
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 and No. 3 at the muzzle, swing the piece 180° clockwise.
Prior to the turn, the gunner sets the brake on the pivot
wheel (the wheel adjacent to the gunner’s post) and when
the turn is completed, sets the other brake. Assisted by No. 3
at the muzzle, Nos. 2 and 5 raise the trail and place the
lunette in the firing position, then lower the trail to the
ground. No. 4 starts unloading ammunition, tools, and acces-
sories from the truck, and places 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, 3, and
5 assist No. 4 in completing the unloading. When the unload-
ing has been completed, the chief of section commands or
signals drive on. The gunner and all cannoneers take their
posts (par. 22).
(2) The trucks . — At the command drive on, the trucks
move out and are conducted by the first sergeant to their
previously designated position.
175765* — 39 3
13
16-18
SERVICE OF THE PIECE
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.
d. To fire to the flank. — The command is: ACTION RIGHT
(LEFT) . The movement is executed according to the princi-
ples of action front, with the following modifications: After
uncoupling, the trail is turned 90° away from the direction
of fire, and the piece is run forward sufficiently to clear the
track made by the truck; articles unloaded from the truck
are placed on the ground so as to clear the track made by
the truck.
■ 17. Coupling. — a. The pieces being in position and in 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 unex-
pended 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,
assisted by No. 3 at the muzzle, 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 AND MARCH ORDER,
HORSE-DRAWN UNITS
■ 18. To Prepare for Action. — a. The carriage being in
position, unlimbered, the command is: PREPARE FOR
ACTION. Duties of individuals are as follows:
(1) Chief of section. — (a) Supervises the work of the
cannoneers.
(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
14
SERVICE OF THE PIECE
18
completed, reports to the executive, “Sir, No. (so and so)
in order” or reports any defects which the section cannot
remedy without delay.
(2) Gunner. — (a) Removes the sight -support cover,
(b) Receives the sight from No. 1, seats it, and sees that
the deflection setting is plateau 0, drum 100.
(c) Releases the elevating latch; operates the elevating
and the traversing mechanisms, leaving the piece in the
center of its traverse on the axle.
( d ) Sets site zero and levels the bubble.
(e) Opens the sight -extension -bar case.
(/) Takes his post.
(3) No. 1. — ( a ) Removes the sight from its case and
passes it to the gunner.
(b) Operates the range -crank handle; sets the range at
3,000.
(c) Gives waste to No. 2 for distribution to the cannoneers.
id) Operates the breech mechanism; sets the safety piece
in the firing position.
(e) Examines the breechlock, chamber, and bore, clean-
ing any parts requiring it; leaves the breech open.
(/) Removes the sponge -and -rammer staff from the travel-
ing position, assembles it, and leans it against the front
of the caisson, sponge up.
( g ) Takes his post.
(4) No. 2. — (a) Runs around the right of the piece and
lowers the right piece apron.
(b) Removes the breech cover and places it on top of
the caisson.
(c) Places the trail handspike in the firing position.
(d) Distributes waste to the cannoneers.
(e) Takes his post.
(5) No. 3. — (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
caisson.
(d) Sets the fuze-setter scales at corrector 30, range 3,000.
( e ) Takes his post.
(6) No. 4. — (a) Assists No. 3 to lower the caisson apron
and to raise the caisson door.
15
18—19
SERVICE OF THE PIECE
(b) Takes a fuze box from the caisson rack and places
it on the footboard.
(c) Puts a round of shrapnel in the fuze setter.
(d) Takes his post.
(7) No. 5 — (a) Removes the aiming stakes, runs around
the left of the caisson, and leans them against the left front
of the caisson, point down.
<b) Lowers the left piece apron.
(c) Removes the muzzle cover, placing it on the caisson
pintle.
(d) Removes the breech cover from the top of the caisson
and hangs it over the muzzle cover on the caisson pintle.
( e ) Sets out the aiming stakes when directed by the chief
of section (par. 38) .
(/) Takes his post.
b. The limbered carriages may be partially prepared for
action before reaching the firing position. The duties of
the cannoneers are the same as when the carriages are un-
limbered, but only such operations as are practicable are
carried out before the carriages are unlimbered. Immedi-
ately after establishing the carriages in position, preparation
for action is completed without command, and the cannon-
eers 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
carriages have been unlimbered. In case this is not desired,
the caution, “Do not prepare for action,” must be given.
■ 19. Posts of the Cannoneers, Carriages Unlimbered. — a.
The carriages having been unlimbered, 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 2 yards
from the end of the trail, on the side opposite the executive.
(2) Gunner. — Immediately in rear of the cannoneer's seat,
on the left of the trail of the piece.
(3) No. 1.— Immediately in rear of the cannoneer’s seat,
on the right of the trail of the piece.
(4) No. 2 . — Two feet in rear of the gunner, covering him.
16
SERVICE OP THE PIECE
19—20
(5) No. 3. — Two feet in rear of the caisson chest, on the
right of the caisson trail.
(6) No. 4. — Two feet in rear of No. 3, covering him.
(7) No. 5. — Two feet in rear of No. 2, covering him.
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.
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.
figure 5. — Posts of the cannoneers, carriages unllmbered.
■ 20. March Order. — a . Duties of individuals. — The car-
riages being unlimbered 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 can-
noneers.
(b) Inspects the materiel; makes sure that the piece is
not left loaded ; 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 without delay.
17
20
SERVICE OF THE PIECE
(2) Gunner. — (a) Sets the deflection at plateau 0, drum
100 .
(b) Removes the sight, taking care to lift the sight column
directly upward with both hands so as not to bend it, and
passes it to No. 1.
(c) Traverses the piece to the center of the axle and ele-
vates it until it rests on the traveling lug.
( d ) Locks the elevating handwheel.
( e ) Closes the vial cover of the site level, first removing
the dust and grit.
(/) Assists No. 1 in raising the brake, if lowered.
(g) Puts on the sight-support cover.
(h) Secures the sight extension bar.
(0 Takes his post.
(3) iVo. 1 . — ( a ) Assists the gunner in elevating the piece
on to its traveling lug, keeping the range setting between
3,500 and 5,500, but habitually at a different setting.
(b) Receives the sight from the gunner and replaces it
In the case, collimator toward the inside.
(c) Closes the breech and sets the safety piece in the
traveling position.
(d) Assists the gunner in raising the brake, if lowered.
(e) Unscrews the sponge-and-rammer staff and places it
in the traveling position.
(/) Takes his post.
(4) No . 2. — (a) Secures the trail handspike in the traveling
position.
(b) Replaces the breech cover and secures it.
(c) Raises and secures the right piece apron.
( d ) Takes his post.
(5) No. 3. — (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.
id) 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.
(g) Takes his post.
(6) IVo. 4.— (a) Assists No. 3 in setting fuzes back at safe.
18
SERVICE OF THE PIECE
20-21
(b) Replaces or otherwise disposes of unused ammuni-
tion. Bel ore replacing any round in the caisson chest , he
vnll 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.
(7) No. 5. — (a) Runs around the left of the caisson and
removes the breech cover from the caisson pintle and places
it on top of the caisson.
(b) Replaces the muzzle cover.
(c) Raises and secures the left piece apron.
(d) Secures the aiming stakes and places them in the
traveling position.
(e) Takes his post.
b. To resume fire in another position . — (1) If it is in-
tended to resume filing shortly, but in another position, so
that the limbering of the pieces is necessitated, the command
march order is not given. In this case, at the command
for limbering, only such of the operations incident to march
order are performed as are necessary for the movement
of the piece and caisson and for the care and security of
the equipment.
(2) If the command march order is given while the pieces
are limbered, the operations pertaining to march order are
completed as described above.
Section VIII
PREPARATION FOR ACTION AND MARCH ORDER,
TRUCK-DRAWN UNITS
■ 21. To Prepare for Action. — a. The pieces being in posi-
tion, uncoupled, the command is: PREPARE FOR ACTION.
The gunner and Nos. 1, 2, and 5, working together under the
supervision of the chief of section, remove the gun cover. No.
5 folds it neatly and places it on the ground 1 yard to the
right of the right piece wheel. Thereafter the duties of
individuals are as follows:
(1) Chief of section. — (a) Supervises the work of the
cannoneers.
19
21
SERVICE OF THE PIECE
( b ) Inspects the materiel; verifies the fact that the recoil
mechanism contains the proper amount of oil (TR 1305-75 A
(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 sight-support cover.
(b) Receives the sight from No. 1, seats it, and sees that the
deflection setting is plateau 0, drum 100.
(c) Releases the elevating latch; operates the elevating
and the traversing mechanisms, leaving the piece in the
center of its traverse on the axle.
(d) Sets the site at zero and levels the bubble.
(e) Opens the sight -extension-bar case.
(/) Takes his post.
(3) No. 1.— (a) Removes the sight from its case and passes
it to the gunner.
(b) Operates the range-crank handle; sets the range at
3,000,
(c) Operates the breech mechanism; sets the safety piece
in the firing position.
(d) Examines the breechblock, chamber, and bore, cleaning
any parts requiring it; leaves the breech open.
(e) Removes the sponge-and-rammer staff from the trav-
eling position, assembles it, and places it on the gun cover.
(/) Takes his post.
(4) No. 2. — ( a ) Lowers the left piece apron.
(b) Removes the breech cover and places it on the gun
cover.
(c) Places the trail handspike, for those carriages thus
equipped, in the firing position.
(d) Distributes waste to the cannoneers.
(e) Takes his post.
(5) No. 3. — (a) Places the fuze setter in position.
(b) Gives waste to No. 2 for distribution to the cannoneers.
(c) Sets the fuze-setter scales at corrector 30, range 3,000.
(d) Puts a round of shrapnel in the fuze setter.
(e) Assisted by No. 4, arranges the ammunition and tools
in an orderly and convenient manner to the left of the piece.
(/) Takes his post.
20
SERVICE OF THE PIECE
21-23
(6) No. 4. — (a) Assists No. 3 to arrange the ammunition
and tools.
(b) Takes his post.
(7) No. 5. — (a) Lowers the right piece apron.
(b) Removes the muzzle cover and places it on the gun
cover.
(c) 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.
( d ) Takes his post.
b. The coupled pieces may be partially prepared for action
before reaching the firing position. The duties of the can-
noneers are the same as when the pieces are uncoupled, but
only such operations as are practicable are carried out be-
fore the pieces are uncoupled. Immediately after establish-
ing the piece in position, preparation for action is com-
pleted without command, and the cannoneers take their
posts for firing the piece.
c. If prepare for action has not been ordered before the
piece is established in the firing position, the command ha-
bitually is given by the chief of section as soon as the piece
has been uncoupled. In case this is not desired, the caution,
“Do not prepare for action,” must be given.
■ 22. Posts of the Cannoneers, Pieces Uncoupled. — The
posts of the cannoneers, pieces uncoupled, are as given for
the horse-drawn battery except that the position of No. 3
is 2 feet to the left of and on line with No. 2 (par. 19 and
fig. 5).
■ 23. March Order. — a. Duties of individuals . — The pieces
being 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, 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 without delay.
175765
21
23
SERVICE OF THE PIECE
(2) Gunner. — (a) Sets the deflection at plateau 0, drum
100 .
(b) Removes the sight, taking care to lift the sight column
directly upward with both hands so as not to bend it, and
passes it to No. 1.
(c) Traverses the piece to the center of the axle and
elevates it until it rests on the traveling lug.
( d ) Locks the elevating handwheel.
(e) Closes the vial cover of the site level, first removing
the dust and grit.
(/) Puts on the sight-support cover.
(fif) Secures the sight extension bar.
( h ) Takes his post.
(3) No . 1. — (a) Assists the gunner in elevating the piece
on to its traveling lug, keeping the range setting between
3,500 and 5,500, but habitually at a different setting.
<b) Receives the sight from the gunner and replaces it in
the case, collimator toward the inside.
(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 > Takes his post.
(4) JVo. 2. — (a) Secures the trail handspike in the travel-
ing position.
(b) Replaces the breech cover and secures it.
<c) Raises and secures the left piece apron.
(d) Takes his post.
(5) No. 3. — ( 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 unit assure himself that all
fuzes have been set at safe .
</) Takes his post.
(6) No. 4. — (a) Assists No. 3 to prepare ammunition and
tools for loading into the truck.
(b) Takes his post.
22
SERVICE OF THE PIECE
23-24
(7) No. 5. — (a) Replaces the muzzle cover.
(b) Raises and secures the right piece apron.
(c) Secures the aiming stakes.
C d) Takes his post.
(8) The gunner and Nos. 1, 2, and 5, working together
under the supervision of the chief of section, replace the
gun cover.
b. To resume fire in another position. — (1) If it is intended
to resume firing shortly, but in another position, so that the
coupling of the pieces is necessitated, the command march
order is not given. In this case, at the command for cou-
pling, only such of the operations incident to march order are
performed as are necessary for the movement of the piece
and for the care and security of the equipment.
(2) If the command march order is given while the pieces
are coupled, the operations pertaining to march order are
completed as described above.
Section IX
DUTIES IN FIRING
* 24. 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 site and deflection,
and lays and refers the piece.
(3) No. 1 sets the announced range, opens and closes
the breech, and fires the piece.
(4) No. 2 loads the piece.
(5) No. 3 operates the fuze setter and screws fuzes in
shell.
(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 gives general direction to the piece.
b. The duties of the gunner and Nos. 1, 2, and 5 are mu-
tually dependent. The same is true of Nos. 3 and 4.
23
25
SERVICE OF THE PIECE
KB 25. Chief of Section. — a. Enumeration of duties. — XI) As-
sisted by the gunner, 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
referring 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.
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 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
gunner’s quadrant, the piece loaded, and the breechblock
closed, the chief of section places the quadrant on the quad-
rant seat on the breech hoop, with the words “line of fire”
at the bottom and the arrow pointing toward the muzzle.
24
SERVICE OF THE PIECE
25
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 subsequent setting, so that the quadrant bubble will in
each case be viewed from the same angle.
( d ) The chief of section causes the gunner to set the site
at zero (when the required elevation permits) and to center
the bubble of the angle-of-site level by manipulating the
elevating handwheel. No. 1 operates the range crank until
the quadrant bubble is slightly in front of the center. The
chief of section then causes the gunner to elevate or depress
the piece until the bubble is centered, being careful that
the last motion of the bubble is from front to rear .
(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 (Cl) above). He then moves
the index arm until the bubble passes to the end of the vial
away from the hinge of the index arm. He then slowly
lowers the index arm until the bubble just passes to the
end of the vial toward the hinge. He then allows the index
arm to engage the arc and slides the level along the index
arm until the bubble is accurately centered. He then
removes the quadrant and reads and announces the elevation
thus set, for example, “Elevation No. (so and so) , (so much)
(3) To measure the minimum elevation or minimum
range.
(a) I. Elevation . — The command is: MEASURE THE
MINIMUM ELEVATION. The chief of section,
sighting along the lowest element of the bore,
causes the gunner to operate the elevating mech-
anism until the line of sight just clears the crest.
He then measures the quadrant elevation as de-
scribed in (2) above and reports the angle read
from the gunner's quadrant to the executive,
thus, “Minimum elevation, No. (so and so), (so
much)
25
25 SERVICE OF THE PIECE
2. Range. — The command is: MEASURE THE MIN-
IMUM RANGE, SITE (SO MUCH). The chief
of section causes the gunner to set the site an-
nounced and to center the bubble of the angle-of-
site level by operating the elevating handwheel.
Sighting along the lowest element of the bore,
he then causes No. 1 to operate the range crank
until the line of sight just clears the crest. No.
1 then reads the range setting, and the chief of
section reports this range as the minimum range
to the executive, thus, “Minimum range, No. (so
and so), (so much), site (so much).”
(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
gunner to chalk it on the shield.
(4) To indicate to the gunner the aiming point, the re-
ferring point , or the target. — Whenever an aiming point, a
referring point, or a target has been designated by the execu-
tive, the chief of section will make sure that he has prop-
erly identified the point in question. He will then indicate
it to the gunner. If there is any possibility of misunder-
standing, the chief of section will turn the sight until the
horizontal and vertical lines are on the point designated.
(5) To follow fire commands. — The chief of section will
follow the fire commands mentally. He will not repeat
the commands, but will be prepared to give any element of
the last command to any cannoneer who has failed to
hear it.
(6) To indicate when the piece is ready to fire. — When
arm signals between the chief of section and the execu-
tive 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
26
SERVICE OF THE PIECE
25
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 cannoneers are in their proper places. He will
require the cannoneers to stand clear of the piece for the first
round.
(8) To report errors and other untisual 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 gun-
ner reports that the aiming stakes are out of alinement with
the sight, the chief of section will report that fact and
request instructions (par. 39). Likewise, other unusual in-
cidents that affect the service of the piece are promptly
reported by the chief of section.
(9) To conduct prearranged fire schedules . — Whenever
the execution of prearranged fires is ordered, the chief of
section will conduct the fire of his section in strict con-
formity to the schedules prescribed.
(10) To record basic data . — Data of a semipermanent
nature will be recorded in a notebook by the chief of sec-
tion. This includes such data as minimum elevations; base
deflections, including aiming points used; prearranged fires
when prepared schedules are not furnished; safety limits in
elevation and deflection; number of rounds fired, with
the date and hour; and calibration corrections when
appropriate.
(11) To observe and check the functioning of the mate-
riel . — The functioning of all parts of the materiel will be
observed closely during firing. Before the piece is fired, the
chief of section verifies the fact that the recoil mechanism
contains the proper amount of oil and thereafter carefully
observes the functioning of the recoil system. Any evidence
of trouble (par. 53) is reported promptly to the executive.
(12) To assign duties when firing with reducea person-
nel . — Whenever the personnel of the section serving the piece
27
25—26
SERVICE OF THE PIECE
is temporarily reduced in numbers below that indicated in
this manual, the chief of section will make such redistribu-
tion of duties as will best facilitate the service of the piece.
■ 26. Gunner. — a. Enumeration of duties. — (1) (a) To set
or change the deflection.
(b) To apply the deflection difference.
(c) To set the angle of site.
(d) To lay for direction.
(e) To lay for elevation.
(/) To call * ‘Ready.”
( g ) To refer the piece.
( h ) To record base deflection.
(i) To measure a deflection.
( j ) To measure an angle of site.
(k) To give the command to fire during direct laying on
a moving target.
(2) For indirect laying without the gunner's quadrant , the
gunner performs duties prescribed in (1) (a), (b), (c) , (d) ,
(e) , and (/) above,
(3) For indirect laying with the gunner's quadrant , the
gunner performs duties prescribed in (1) (a), (b), (d), ( e ),
and (/) above.
(4) For direct laying, the gunner performs duties pre-
scribed in (1) (a), (d), (e), (/), and ( k ) above.
(5) When directed, the gunner performs duties prescribed
in (1), (fir), ( h ), (z), and (j) above,
b. Detailed description of certain duties. — (1) To set or
change the deflection. — (a) To set the deflection.— The gun-
ner is first taught to read deflections set on the sight and then
to set the deflections announced. At the command, for ex-
ample, plateau 4, drum 125 , the gunner first presses down the
collimator cover with his right hand, at the same time turning
the sight column so that the index is opposite the plateau
graduation (4 in this case) , and releases the sight column. He
then loosens the clamp lever of the drum, turns the drum
with the left hand until the graduation 125 is opposite the
index, and tightens the clamp lever. The last motion of the
drum should always be in the direction of increasing
deflection.
28
SERVICE OF THE PIECE
26
(b) To change the deflection .
1. The gunner should be trained always to grasp the
deflection drum with the left thumb on top, since
the command for changing the deflection, when
applied on the drum alone, then will indicate the
direction in which he should move his thumb in
turning the drum ((2) id) below). He also
should be taught that turning the drum toward
the muzzle (away from him) decreases the de-
flection set on the sight and results in moving
the muzzle to the right when the piece is laid at
the new deflection. Similarly, turning the drum
toward the breech (toward himself) increases the
deflection and results in moving the muzzle to
the left when the piece is laid.
2. When the deflection change can be made on the
drum alone, the gunner uses the drum as a
counter and turns it in the proper direction until
the number of tens and units have passed the
index. The deflection having been set at plateau
4, drum 125, if a subsequent command be, for
example, right 65, the gunner turns the drum
by moving his thumb toward the muzzle (away
from him), setting off six tens and five units.
As turning the drum toward the muzzle decreases
the deflection , the result will be read on the drum
as 125 minus 65 equals 60, or plateau 4, drum 60,
the plateau reading remaining unchanged.
3. If the change, although less than 200 mils, cannot
be made on the drum alone, the gunner men-
tally subtracts the change from 200, changes the
plateau one division in the direction announced
without turning the drum, and then applies the
result of the subtraction to the drum in the oppo-
site sense. For example, if the setting be plateau
4, drum 125, and the command left 170 were
given, 200 minus 170 equals 30. The sight column
is turned left (increasing deflection) one division
to plateau 6 ; the drum is then turned toward the
muzzle (decreasing deflection) three tens or 30
175765 ° — 39 -
5
29
26
SERVICE OP THE PIECE
mils. The resultant setting would thus be pla-
teau 6, drum 95.
4. A deflection change of more than 200 mils can be
separated into a change of one or more divisions
on the plateau, which is applied at once, and a
remainder less than 200 mils, which is applied in
the manner described above. Thus, right 54 o
requires a change of two divisions (400 mils) on
the plateau and 140 mils on the drum.
5. A new setting, after a deflection change, also can
be calculated arithmetically. The initial setting
is converted into mils. Hie change is then added
or subtracted from this number, the result con-
verted into plateau and drum, and the setting
changed accordingly. For example, if the initial
setting were plateau 14, drum 55, and the com-
mand RIGHT 625 were given: m j s
Plateau 14, drum 55 equals 1,455
Right (decreasing the deflection) • _ 625
Result 830
Converted to a new setting, 830 mils equals
plateau 8, drum 30.
(2) To apply the deflection difference .■ — (a) The com-
mand is: ON NO. (SO AND SO) OPEN (CLOSE) (SO
MUCH). The gunner of the piece indicated in the com-
mand does not change the deflection set on his sight. Each
of the other gunners changes his sight setting by the num-
ber of mils specified in the command if his piece is next
in line to the piece indicated; by twice this number of mils
if his piece is the 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) When the deflection difference can be applied on
the drum alone, 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 his drum so as to move the muzzle away
from No. 1, setting off 5 mils once; the gunner on No. 3
turns his drum so as to move the muzzle away from No. 1,
setting off 5 mils twice, a total of 10 mils; the gunner on
No. 4 turns his drum so as to move the muzzle away from
No. 1, setting off 5 mils three times, a total of 15 mils.
30
SERVICE OF THE PIECE
26
(c) Should the command be, for example, on no. 3 close
10 , the gunner on No. 1 turns his drum so as to move the
muzzle toward No. 3, setting off 10 mils twice, a total of
20 mils; the gunner on No. 2 turns his drum so as to move
the muzzle toward No. 3, setting off 10 mils once; the gunner
on No. 3 makes no change; the gunner on No. 4 turns his
drum so as to move the muzzle toward No. 3, setting off
10 mils once.
( d ) In turning the drum the gunner must remember that
the movement of the muzzle will follow the movement of
his thumb. For example, grasping the drum with his left
thumb on top, to move the muzzle to the right, his thumb
moves toward the muzzle, and he can be taught to visualize
the movement as pushing the muzzle away from him (to
the right) ; to move the muzzle to the left, his thumb moves
toward the breech, and he can be taught to visualize this
movement as pulling the muzzle toward him (to the left) .
(e) When the deflection difference cannot be applied on
the drum alone, the gunner mentally calculates the change
and applies it in a manner similar to that previously de-
scribed for a deflection change.
(/) In order to insure rapid and accurate deflection
changes, the gunner must be given much practice, with con-
stant checking of results. He must be trained and instructed
so thoroughly in this respect that he instinctively will turn
the sight column and the drum in the proper direction in
response to the command right (left) .
( g ) When a deflection change and a deflection difference
are announced at the same time, for example, right 3o, on
no. i close 5, both of which affect the gunner's piece, he
will first set off the deflection change and then apply the
deflection difference.
(3) To set the angle of site . — The gunner is first taught
to read angle -of -site settings and then to set announced
angles of site. To set an angle of site, the gunner turns
the wing knob until the graduation announced is opposite
the index. In setting the angle of site, it is necessary that
the gunner look squarely at the angle -of -site dial.
(4) To lay for direction. — (a) Direct laying . — The deflec-
tion having been set, the gunner traverses the piece by
31
26
SERVICE OP THE PIECE
turning the traversing handwheel with his right hand until
the vertical line of the sight is on his part of the target.
If the amount of movement necessary to lay on the target
is greater than can be obtained by traversing, the trail must
be shifted. To shift the trail, the gunner commands or
signals muzzle right (left). No. 5 at the trail handspike
(par. 31), sighting along the line of metal, points the piece
directly at the target (except when firing by individual sec-
tions at fast-moving targets as prescribed in par. 37), and
the gunner brings the vertical line of the sight accurately
on the target by means of the traversing handwheel.
(t>) Indirect laying. — The deflection having been set, the
gunner brings the vertical line of the sight on the aiming
point either by traversing the piece or by shifting the trail
and traversing the piece. To shift the trail, the gunner
commands or signals muzzle right (left) . No. 5 shifts the
trail as indicated by the gunner until the vertical line of the
sight is approximately on the aiming point. The gunner
then completes the laying by operating the traversing hand-
wheel until the vertical line of the sight is on the aiming
point.
(c) 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 line of the sight to approach
the aiming point from the left. The gunner should habitu-
ally lay with the vertical line of the sight on exactly the
same portion of the aiming point or target for each round.
(5) To lay for elevation.— (a) Direct laying.— When the
target is stationary, the range having been set, the gunner
lays for elevation with the sight for the first round by
manipulating the elevating handwheel until the horizontal
line of the sight is at the base of the target. Then, without
changing the laying of the piece, he centers the bubble of
the angle-of-site level by changing the angle-of-site setting.
Laying for subsequent rounds is accomplished by means of
the angle-of-site level, without changing the site setting.
When the target is moving, for each round, the range having
been set, the piece is laid for elevation by means of the
horizontal line of the sight (par. 37).
32
SERVICE OF THE PIECE
26
(f>) Indirect laying.
1. Without the gunner's quadrant . — The angle of site
and the range having been set, the gunner turns
the elevating handwheel with his right hand
until the bubble of the angle -of -site level is
centered. He keeps the bubble centered
throughout the firing. The last movement of
the handwheel must be such that the bubble
moves from front to rear. In centering the
bubble, the gunner must be careful to look
squarely at it.
2. With the gunner's quadrant. — See paragraph 25.
(c) In all cases of laying for elevation , the last movement
of the elevating handwheel must be in the direction of de-
pression so as to raise the breech, thereby taking up any lost
motion in the elevating mechanism.
(6) To call “Ready.” — The piece having been laid for
direction and No. 1 having called “Set” the gunner verifies
k the laying, moves his head clear of the sight, and calls
“Ready’" to indicate that his piece is ready to be fired.
(7) To refer the piece.— The piece having been laid for
direction, to refer the piece, the command is: 1. aiming
point (so and so), 2. REFER. Without disturbing the lay-
ing of the piece, the gunner brings the vertical line of the
sight on the new aiming point (referring point) . He then
reads and announces the deflection thus set and records the
deflection and the referring point on the shield. 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 left front. Frequently it will be
necessary to use the aiming stakes as referring points, par-
ticularly for night use.
(8) To record base deflection.— At the command record
base deflection, the gunner records the deflection set on
his sight upon some convenient part of the carriage or upon
a data board (par. 48).
(9) To measure a deflection.— The command is: 1. aim-
ing POINT (SO AND so), 2. MEASURE THE DEFLECTION.
The piece having been established in direction, the gunner
33
26-27
SERVICE OF THE PIECE
turns the sight until the vertical line is on the aiming point.
He then reads and announces the deflection.
(10) To measure an angle of site. — The command is:
1. target (So and so), 2. MEASURE THE SITE. The piece
having been laid on the target for direction, the gunner,
using the elevating handwheel, brings the horizontal line
of the sight to the base of the target and centers the bubble
of the angle-of-site level by changing the angle-of-site
setting. He then reads and announces the angle of site.
(11) To give the command to fire during direct laying on
a moving target. — When firing at moving targets with direct
laying, whether the firing is by battery or by individual
section, the piece is fired at the gunner’s command fire.
fl 27. No. 1. — a. Enumeration of duties. — (1) To set the
range.
(2) To open and close the breech.
(3) To call “Set.”
(4) To fire the piece.
(5) To use the rammer.
b. Detailed description of certain duties. — (1) To set the
range. — No. 1 is first taught to read range settings on the
graduated range scale, and then to set ranges. To set a
range, No. 1 grasps the range crank handle with his right
hand, presses it in to release it, turns it until the graduation
announced is opposite the index, and releases the handle.
He is first taught to set off ranges to the nearest hundred
and then to the nearest twenty-five. To take up lost
motion, the last motion in setting the range should be in
the direction of decreasing range.
, (2) To open and close the breech. — (a) To open the
breech. — For the first round. No. 1 cocks the latch by push-
ing forward the plunger in the handle; the recoil of the gun
automatically cocks the latch for subsequent rounds. No. 1
then grasps the operating handle with both hands, palms
down, with the fingers fully closed around 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 forearms and wrists so as to eject the car-
tridge 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
34
SERVICE OF THE PIECE
27
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)).
( b ) To close the breech . — No. 1 grasps the operating handle
with his left hand, moves the handle downward, and drops
his hand to his side.
(c) Opening and closijig 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, it 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 with
both hands.
(3) To call “Set." — When No. 1 has completed his duties in
laying the piece and closing the breech, he calls "Set."
(4) To fire 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. I grasp
35
27-28
SERVICE OF THE PIECE
the lanyard until the gunner calls Ready ( Fire ).” Ordi-
narily the piece is fired with No. 1 seated on the seat; 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 Jink, steps clear, and fires as previously described.
No. 1 detaches the long lanyard immediately after each round
is fired. In case of a misfire, the instructions contained in
paragraph 46 will be followed .
(5) To use the rammer. — The sponge and rammer will be
handled by No. 1 only. The rammer is used to extract unfired
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 45 will be followed.
■ 28. 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 giving direction to
the piece.
b. Detailed 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, then, con-
tinuing 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 mate-
riel. To prevent premature bursts caused by projectiles be-
ing struck on the fuze by the piece in recoil , a round to be
36
SERVICE OF THE PIECE
28-29
loaded will be held well out of the path of 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 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.
■ 29. 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 . F5i* subsequent rounds, the cor-
rector setting is increased (decreased) at the command tip
(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 data on the bracket
fuze setter, No. 3 turns the corrector -worm knob with his
right hand until the graduation on the corrector scale, cor-
responding 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 coincidence with the index engraved on the rim of the
case. He then turns the knob on the range-scale worm until
the graduation on the range scale, corresponding to the
range announced, is in coincidence with the index on the
index bar.
id) 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
29
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.
( g ) 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. The
fuze setter is then turned ii^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 seating 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
29-30
(4) To remove fuzes 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 unscrew-
ing must be stopped at once and the shell disposed of as
directed by the executive.
■ 30. No. 4. — a. Enumeration of duties . — (1) To remove am-
munition from the chest or other container and to clean
and prepare it for firing.
(2) To set the fuze when the bracket fuze setter is used.
(3) To hold the round while No. 3 sets the fuze, when
the hand fuze setter is used.
(4) To hold the round while No. 3 screws the fuze into
the shell.
(5) To pass the round to No. 2.
b. Detailed description of certain duties . — (1) To remove
ammunition front the chest or other container , and to clean
and prepare it for firing. — No. 4, when time permits,
arranges the rounds so that they are within easy reach or
partially removes them from their compartments. To re-
move a round from the chest (in units equipped with cais-
sons), No. 4, standing with his left side toward the chest,
grasps the base of the cartridge case with his right hand
and pulls the round to the rear, across the front of his body,
grasping the projectile in the 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 burs can be removed with
a file.
(2) To set the fuze when the bracket fuze setter is used . —
When the command corrector (so much) is given. No. 4 pro-
cures a round of shrapnel, removes the waterproof cap of
the fuze, and inserts the point of the projectile in the
bracket fuze setter, taking care that the lug nearest the
point of the fuze engages in the groove in the fuze setter.
When No. 3 has called “Cut,” No. 4 turns the projectile with
steady and uniform motion in a clockwise direction
39
30
SERVICE OF THE PIECE
until further movement is stopped. In turning the pro-
jectile, 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 directly out of the fuze setter, taking care not to strike
the lugs of the fuze against any part of the fuze setter.
The time of burning may be read from the graduated ring
of the fuze. When directed by the chief of section. No. 4
will read and announce the time of burning after setting
the fuze. A time fuze which has been set for any desired
time of burning can be reset to S (Safe) by setting the
fuze-setter range ring to S, the corrector to 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 con-
tainer by No. 4. If the command percussion is given, No. 4,
after removing the waterproof cap, passes the round directly
to No. 2 for loading.
(3) To hold the round while No. 3 sets the fuze , when the
hand fuze setter is used. — No. 4 holds the round while No. 3
sets the fuze. No. 4 procures the round, removes the water-
proof cap, faces to the right, and partially kneels on the right
knee. He places the base of the cartridge case on his right
thigh just above the knee. He grasps the round with both
hands, the right arm resting on his right thigh, the left
arm braced against his left thigh. The round is held firmly,
pointing upward in the general direction of No. 3’s head,
while No. 3 sets the fuze.
(4) To hold the round while No. 3 screws 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
40
SERVICE OF THE PIECE
30-32
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.
(5) 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 grasp the base of the cartridge case
with his right hand.
■ 31. No. 5. — a. Enumeration of duties . — (1) To shift the
trail.
(2) To keep empty cartridge cases out of the way.
b. Detailed description of certain duties. — (1) To shift
the trail. — When laying for direction involves shifting the
trail, the gunner and No. 5 work together. To shift the trail.
No. 5 stands immediately in rear of the trail handspike
(the lunette for pieces not equipped with the trail hand-
spike), feet about 18 inches apart, and grasps the hand-
spike (lunette) with both hands. The gunner causes the
trail to be shifted by the command muzzle right (left), or
other suitable indication, until the vertical line of the sight
is approximately on the target (aiming point). When
direct laying is used. No. 5 sights along the line of metal and
shifts the trail so as to point the piece directly at the target.
In the case of direct laying on moving targets (except when
firing by individual sections at fast -moving targets as pre-
scribed in par. 37), No. 5, at the command target (so and
so), points the piece directly at the target, but does not
shift the trail again until the gunner commands or signals
MUZZLE RIGHT (LEFT).
(2) To keep empty cartridge cases out of the way . — No. 5
takes the cases as they are ejected and throws them well
to the rear of the piece.
Section X
ADDITIONAL INFORMATION ON THE SERVICE OF THE
PIECE
■ 32. Use of the Sight Lines, Collimator Sight. — The
sight lines in the collimator appear as a white cross on a
black background. The lines are vertical and horizontal.
The gunner is taught to discern these lines and to prolong
41
32-35
SERVICE OF THE PIECE
them outside the collimator to obtain coincidence with ex-
ternal objects. The general method used for this is as
follows: Close the right (left) eye, look through the col-
limator along its axis from as great a distance as possible,
then move the eye up and down rapidly so as to prolong
the vertical line, then sideways to prolong the horizontal
line. As the gunner becomes more experienced, the amount
of movement of the eye necessary to obtain coincidence with
external objects becomes less. Some men find it convenient
to sight with both eyes open, thus avoiding the necessity of
moving the eye.
* 33. Use of the Sight Extension Bar. — The use of the sight
extension bar is exceptional and must be avoided whenever
possible as it frequently leads to inaccuracy. When its use
is necessary, the gunner places it in the sight socket. This
raises the sight above the top of the shield and enables the
gunner to sight on aiming points otherwise obscured from
view. As soon as the piece has been laid, he removes the
sight extension bar, replaces the sight column in the sight
socket, and refers the piece. The sight extension bar must not
be left in position during firing.
■ 34. 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 laying, the gunner and any other cannoneers who
have duties in connection with laying the piece invariably
will be required to verify the laying after the breech has
been closed. When the piece must be established on uneven
ground, the amount of cant of the axle is measured with the
gunner's quadrant and reported by the chief of section to
the executive.
■ 35. To Raise and Lower the Brake, 75-mm Gun, M1897,
Horse-Drawn. — The chief of section may cause the brake
to be lowered after the trail has been seated.
a. To lower the brake . — The gunner stands between the
left wheel and the trail; No. 1 stands between the right wheel
42
SERVICE OF THE PIECE
35-37
and the trail. Each grasps the tie rod on his side near the
brake beam. No. 1 turns the latch pin of the brake-beam
carrier to the right, lifts it as high as possible, and calls
“Heave.” At this signal both lift the brake beam. No. 1 pulls
back the brake-beam carrier, and when the brake beam is
freed both allow it to fall to the ground of its own weight.
b. To raise the brake . — The gunner and No. 1 take the
same positions as for lowering the brake. No. 1 calls “Heave”
and both lift the brake beam. No. 1 then pushes the brake-
beam carrier forward and replaces the latch pin. To secure
the latch pin properly, it may be necessary to repeat the
operation.
* 36. Fire at Will. — a. The piece being in position and pre-
pared for action, in case of sudden attack, when the target
appears at a range of less than 500 yards, the executive may
command: 1. target (so and so), 2. FIRE AT WILL. The
chief of section repeats this command.
(1) No. 1 sets the range at 500; No, 3 sets corrector 30,
range zero; No. 4, if shrapnel is used, sets fuzes continuously.
The gunner, assisted if necessary by No. 5 at the handspike,
keeps the piece laid directly on his part of the target
throughout the firing.
(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 the gunner lays well below the lowest visible element of
the target.
■ 37. To Fire by Individual Sections With Direct Laying
at Moving Targets. — a. The chief of section observes the
target, estimates its range and speed, and gives such direc-
tions to the cannoneers as will aid them in laying and firing
the piece.
43
37
SERVICE OF THE PIECE
b. The gunner traverses the piece to the center of its
traverse and, when directed by the chief of section, sets a
lead in mils for the target on the drum of the sight. As-
sisted by No. 5 at the handspike, who points the piece directly
at the target, the gunner manipulates the elevating and tra-
versing mechanisms until the vertical and horizontal lines
of the sight intersect at the target. The piece is fired at
the command fire of the gunner when the piece is laid, No. 1
has called “Set,” and the chief of section has indicated that
the executive has given the command or signal to commence
firing. Subsequent rounds are fired at the command of the
gunner as soon as the necessary corrections have been made
and the piece is again laid on the target.
c. If the target is moving rapidly in a lateral direction,
the gunner may cause No. 5 to lead the target by pointing
the piece ahead of the target. In this case the gunner com-
mands, for example, lead right (left) (so many) mils. No.
5, using the graduated trail log, float, or shield to measure
off the lead ordered (par. 40) , points the piece ahead of the
target by the number of mils announced by the gunner.
The gunner gives the command to fire as the target reaches
the intersection of the sight lines; if No. 5 has shifted too
much, he traverses the piece to meet the target and gives
the command to fire at the appropriate moment. For sub-
sequent rounds. No. 5 shifts the trail by pointing the piece
ahead of the target by the announced lead immediately
after the piece is fired, until a new lead is announced or
firing ceases. In case the target stops or moves to the
front or rear, the gunner may require No. 5 to cease leading
and point the piece directly at the target. In this case the
gunner commands, for example, lead zero, muzzle right
(left) . No. 5 ceases to lead the target, shifts the trail in
the direction indicated, and points the piece directly at the
target.
d. No, 1 sets the range announced by the chief of section,
calls “Set/* and fires the piece at the gunner’s command
FIRE.
e. No. 2 loads the piece at the command or signal to com-
mence firing and continues to load the piece each time it has
fired and returned to battery, until the command cease
firing is given.
44
SERVICE OF THE PIECE
38-10
■ 38. 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 26b (7). 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 line of the col-
limator and the two aiming stakes are all in the same ver-
tical plane. Any lateral displacement of the piece during
firing can then be detected easily and corrected for as indi-
cated in paragraph 39. For night use, the lights should be
adjusted so that the far one will appear several feet higher
than the near one. The two lights thus will clearly estab-
lish a vertical line on which the vertical line of the collimator
can be laid.
■ 39. 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
section. The gunner continues to lay the piece, using the
far stake, until correction is authorized by the executive.
The piece is then moved back into its original position, or
a correction is made as follows : The gunner lays the piece by
using the far stake, then refers to the near stake, and finally
lays on the far stake with the new reading. The stakes are
then realined by moving the near stake. This correction is
effective only when the stakes have been equally spaced as
indicated in paragraph 38.
■ 40. Trail Logs and Platforms. — a. When soil conditions
are unfavorable and the necessary material can be pro-
cured, the handling of the piece will be greatly facilitated
by the construction and use of improvised wheel mats, trail
logs, and platforms.
b. In order to facilitate shifting the trail in fire against
moving targets, a trail log should be constructed conform-
ing to the arc described by the spade and permitting shifts
of at least 800 mils. A block shaped to provide a smooth
bearing surface against the trail log should be fastened to
45
40—45
SERVICE of the piece
to the spade. The trail log should be graduated every 50
mils; the upper part of the shield and the float should also
be graduated in mils.
■ 41. 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 255 (8).
■ 42. 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.
■ 43. Suspend Firing. — The command suspend firing is
given only when the battery is firing on a prearranged
schedule and a temporary halt in the firing is desired. At
this command, firing is stopped, but settings continue to be
altered in conformity with the schedule. If the piece is
loaded, the chief of section will report that fact to the
executive. Fixing will be resumed at the command resume
firing.
■ 44. 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 not 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. 45). If no change in fuze setting is required
or if the piece is loaded with shell, the new data are set
off, and the firing is resumed.
■ 45. To Unload the Piece. — a. When the command un-
load is given. No. 1 opens the breech, and No. 2, standing
46
SERVICE OF THE PIECE
45—47
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 that
the recess for the fuze is free from any foreign matter.
Under the direct supervision of an officer, he inserts the
rammer head in the bore and pushes it carefully in until
it encloses the the fuze and comes in contact with the pro-
jectile. He pushes the rammer head gently against the
projectile and, if necessary, taps the rammer staff lightly
to dislodge the projectile. He then pushes the projectile
out of the breech while No. 2, standing at the breech, re-
ceives 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.
■ 46. 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.
El 47. Ammunition. — a. Ammunition must be protected from
damage, especially to rotating bands and cartridge cases.
When it is received, it should be sorted into lots and placed
in tlie best available storage. Ammunition data cards should
be retained until after all ammunition pertaining thereto is
expended. Fuzes must not be stored with other components,
and all components should be kept in their waterproof con-
tainers until their early use is anticipated. Protection
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 ammunition, and suitable dunnage below and be-
tween the layers. Protection against hostile fire may be
obtained by the use of Small dispersed stacks, trenches, or
dugouts.
47
47-49
SERVICE OF THE PIECE
b. Care must be exercised to keep sand and dirt out of the
adapter threads of unfuzed 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.
H 48. 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 urgent.
Section XI
CARE AND MAINTENANCE OP MATERIEL
■ 49. 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, in-
cluding disassemblies, are found in the Technical Regula-
tions and Standard Nomenclature lists referred to in para-
graph 2, especially in TR 1305-75A (now TR 320-95) , SNL
C-4, and SNL C-25. Operations not covered therein are the
function of the ordnance maintenance company.
c. In general, the battery is charged with preventive
maintenance, that is, with routine cleaning, lubricating, and
preserving. 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-4 for the M1897 gun, and in SNL C-25 for the
M1897A4 gun, by the symbol %. Unless specifically pro-
hibited, such parts may be installed by the battery mechanic.
For routine care and maintenance, specific duties are as-
signed to individuals, squads, or sections, and a strict ac-
countability for the proper performance of such duties is
enforced.
48
SERVICE OF THE PIECE
49-50
d. Disassemblies which may be performed in the battery
are the following:
Cl) Breech and firing mechanism.
(2) Sweeper plate and guide.
(3) Piston-rod coupler key.
(4) Rocker- arm trunnion caps.
(5) Dismounting of gun from cradle.
(6) Dismounting of cradle from carriage.
(7) Removal of respirator.
(8) Removal of filling and drain plug.
(9) Shields.
(10) Axle.
(11) Elevating-screw pin and range-elevation screw.
(12) Range scale.
(13) Elevating-crank assembly.
(14) On M1897 carriage, removal of wheels, axle collars,
axle washers, brake frames, brake shoes, and brakefork keys.
(15) On M1897A4 carriage, removal of major parts of
high-speed adapter, including axle brackets, compensator as-
sembly, brake assembly, radius rods, seat supports, wheels,
and tires.
■ 50. 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
cutting compound. Powder fouling attracts moisture and
hastens the formation of rust. Therefore, at lulls during
firing and immediately after firing the piece must be thor-
oughly cleaned. At other times it should be cleaned at in-
tervals not exceeding 2 weeks, depending upon the use and
condition. Dirt on nonbearing surfaces can usually be re-
moved 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 54b. The following cleaning ma-
terials 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.
49
50-52
SERVICE OF THE PIECE
(2) Dry-cleaning solvent .— For 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 unfinished or non-
bearing 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 waste , clean rags , and sponges . — For general
cleaning purposes.
b. A division of duties for members of the gun squad in
routine cleaning and maintenance is as follows:
(1) The gunner — the sighting equipment, including the
gunner’s quadrant.
(2) Nos. 1 and 2 — the breech mechanism and bore, the
range scale, and the range-scale shaft.
(3) No. 3 — the fuze setter.
(4) Nos. 4 and 5 — the elevating and the traversing mecha-
nisms, the axle, the roller paths, and the Inclined planes for
the gun slides.
(5) Higher-numbered cannoneers assist in the operations
as directed by the chief of section.
■ 51. Lubrication. — a. Caisson and limber wheel bearings
require Va 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 fit-
tings should be made conspicuous by circling with bright red
enamel.
c. Lubrication instructions for the gun and carriage are
covered in figures 6 and 7.
■ 52. 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-
50
SERVICE OF THE PIECE 52-53
sorbent objects may be deeply contaminated, and even hard
surfaces may be dangerous for 6 to 8 days if the chemical is
not neutralized. Surfaces should be sprinkled with calcium
hypochlorite or chloride of lime, or painted' with a whitewash
made from either. After 2 to 6 hours the lime is washed off
and the materiel rinsed thoroughly with water. When large
quantities 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 disposed by burying.
They must not be burned as the heat will disseminate dan-
gerous vapor.
■ 53. Recoil Mechanism. — a. General . — Battery mainte-
nance of the recoil mechanism is limited to exterior cleaning
and lubrication, draining and filling with recoil oil, adjust-
ment 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. It is especially important that this oil be
kept free of dirt, water, and air bubbles, and that it be not
mixed with other oils. A full reserve of oil for the recoil
system amounts to approximately one-half the contents of
the screw filler. In using the screw filler, care must be exer-
cised 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 . — The indicator is at the bottom of the re-
cess. 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.
b. 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.
51
SERVICE OF THE PIECE
MUZZLE ROLLER , LIFT
S WEE PE R PLATE AND PLUNGERS
JACKET ROLLER ‘FRONT, LEFT
$L i DE S *N D roller PaTHS.LEFT { bVe)
JACKET ROLLER , REAR, LEFT
TRUNNION CAP. LEFT
SIGHT MOUNT, (5 HOltSXd'l
AXLE BRACKET, LEFT. (a>
BRAKE WORM QUADRANT SHAFT (a)
AXLE, EXPOSED SURFACE
AXLE COLLAR, LEFT
TRAVERSING tIAWDWHEEL SHAFT <a>
wheel bearing, left
ANCLE OF SITE HANDWHEEL SHAFT <al
TRAVERSING HANDWHEEL HANDLE
SEaT SUPPORT shaft BRACKET. LEM
elevating yoke bearing, left
SEAT support shaft bushing, left
BORE, breech t FIRING MECH AN|S M (e)
■SLIDE ROD, PAWL AND RaCK (c)
NQT £S;
(Ol PaeKed by Ordnance at annual aver haul.
(b) U« bruen when barrel i* ril raet* <i .
<c) Partially lubricated by aeepaqc. /ram recoil mcchchtim.
(d) Lubricating ail may b«. u«cd if neutral ail ia n«e available,
(el Lubricate bearing parti frequently during firina. Clean and
lubricate dll part 4 immediately after firing.
L U B ft I C ANTS
© Neutral oil
© Lubricating oil - liohtIsaEzo)
■ N com wkaTHE A; HkavtUakJO)
ih mot w path c a .
© Mineral lubricating grease
HOW APPLIED *
A Oiler
O Oil gun
W Brush or cloth
CD Hand packing
Figure 6. — Lubrication
52
SERVICE OF THE PIECE
MUZZLE roller . RIGHT
RESPIRATOR (e>
JACKET ROLLER, FRONT, RICH T
SHOES AND ROLLER PATHS, IUgHT 0>I«)
JACKET roller, rear, right
TRUNNION CAP, RIGHT
BRAKE WORM (a)
AXLE BRACKET, Rich! fa)
AXLE , EXPOSED SURFACE
AXLE COLLAR, R f 6 H T
angle ofsjte worm gear shaft (a)
WHEEL BEAR INC, right
ROCKER SEGMENT (ELEVATING RACK)
ELEVATING CRANK HANDLE
elevating screw pin
Range rack screw
elevating crank shaft ft)
brake beam socket, right
brake latch pin
RANGE scale shaft
SEAT SUPPORT SHAFT BRACKET, R IgNT
seat support shaft bushing, right
OPERATING HANDLE
LUNETTE (a)
APRON HINGES (HOT SHOWN)
WHEN APPLIED
0 Daily, when in constant service, otherwise weekly.
+ Wee k ir . wm eh in constant service, otmerwjie twice montnlv
0 Evert six months
chart, 75 -mm gun, M1897.
53
SERVICE OF THE PIECE
MU2ZU ROLLER. LEFT ®
SWEEPER PLATE, AND PLUNGERS 0
JACKET ROLLER* FRONT, LEFT, ®
SLlDfS A ROLLER PATHS, LEFT, (b)(e) ®
JACKET ROLLER, REAR, LEFT, ©
TRUNNION CAp, LEFT. ©
SIGHT MOUNT (5 HOLES) (<*) ©
AXLE BRACKET, LEFT ©
traversing handwheel shaft, (a) ©
axle , exposed surface ©
drake ro*> pins ©
brake cam shaft ©
AXLE BRACKET, high JPEEO.LCFT ©
ANGLE of site MaNDwHEEl shaft { c \ ©
WHEEL BEARING. LEFT ©
BRAKE lever, left ©
BRAKE LEVER, RIG H T ©
RADIUS ROD , LEFT, FRONT ©
traversing handwheel handle ©
elevating you.t bearing left ®
RADIUS ROD, LEFT, REAR ©
COMPENSATOR, shaft, surface ©
cohpcnsaiok shaft support dracket.lt ®
WISHBOHE, BALL ANO SOCKET ©
60 RC, breech « tiring mECH ANlSMfe) ®
LUNETTE HINGE pin ®
HANDSPIKE ©
lubricants
<D Neutral oil
® Lubricating oil - light <sae 20)
IN COLO WEATHER; NEAVV <SftE30)lN
hot WtATHt R
® Mineral, lubricating grease
® fiber wheel bearing grease
HOW APPLIED
A Oiler
O 0 Oil cl/a/
Grease gun
J53 Brush or cloth
Hano packing
Pigubi: 7. — Lubrication
54
SERVICE OP THE PIECE
0
□
El
m
0
+
+
+
0
0
0 MUZZLE ROLLER . RIGHT
© RESPIRATOR (el
© JACKET ROLLER, FRONT, RIGHT
© SLIDES * ROLLER PaT HS , Rl GHT (bHe)
© JACKET roller, REAR, RIGHT
© trunnion cap, Right
(D AXLE BRACKET, RIGHT
© AXLE
© BRAKE ROD PINS
© BRAKE CAM shaft
© AXLE BRACKET. HIGH SPeEO. RIGHT
© Radius rod. right, front
(D BRAKE LEVER TUBE
@ wheel bearing . right
© ANGLE OF SITE WORM GEAR SHAFT (a)
© ROCKER SEGMENT ItlEVATiNG RACK)
© elevating crank handle
© elevating screw pin
© ELEVATING CRANK shaft <e)
© RADIUS ROD, RIGHT, REAR
© RANGE SCALE SHAFT
© compensator shaft, SURFACE
© COMPENSATOR shaft SUPPORT bracket, rt
© OPERATING HANDLE
© lunette hinge pin
© APRON hinges (NOT SHOWN)
Notes :
(a) — PacKad by Ordnance at anni/al overhaul’
(b) — life brush when barrel it retracted >
(C)"* Partially lubricated Vy Seepage from recall
Meehan i t m
Td)** Lubricating oil maybe ulcd if neutral
oil It not «<roil able .
<e>- luVncotc bearing ports fr*«jut/itly during firing
Cleon and lubricate all partt after firina.
WHEN APPLIED
0 Daily. WHEN IN CONSTANT SERVICE, OTHERWISE, weekly
+ Every two weeks
# Every six months
chart, 75-mm gun, M1897A4,
53
SERVICE OF THE PIECE
c. Operations prior to firing. — (1) Before firing, the reserve
oil should be extracted until an insufficient reserve is indi-
cated, then a full reserve should be established by inserting
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 undue
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 rollers and 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 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 malfunctioning as is indicated below:
56
SERVICE OP THE PIECE
53-54
Malfunction
Cause
Correction
Oil index not
functioning.
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 znay be fired
until the gun returns into bat-
tery with a shock, when re-
serve oil should be extracted, or
the gun fails to return to battery,
when additional oil should bo
inserted.)
Failure of gun to
return to battery.
(1) Insufficient oil re-
serve.
(2) Dirt or obstruction
on the slides, roller paths,
or rollers.
(3) Low nitrogen pres-
sure; excessive internal
friction; damaged slides,
piston rod, or piston.
(1) Insert sufficient fresh oil to
bring the index even with the
rear face of the roar sealing plate.
(2) Clean and lubricate the
slides, roller paths, and rollers.
(3) Send recoil mechanism to
the ordnance maintenance com-
pany 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.
■ 54. Barrel Assembly, Breech Mechanism, and Firing
Mechanism. — a. Operations during firing . — (1) During fir-
ing, all exposed bearing surfaces must be kept clean and
covered with a thin film of lubricating oil. The sweeper
plate and sweeper-plate guide should not allow more than
0.06 inch side play.
(2) Whenever the rate of firing permits, the bore should
be swabbed with clean water and a sponge.
(3) The causes and correction of malfunctioning of the
breech and firing mechanism are given in the following
table:
57
54
SERVICE OF THE PIECE
Malfunction
Cause
Correction
No momentum to
swing of firing hammer.
Broken firing-rack
spring.
Replace spring.
Failure to discharge
when proper percussion
on primer is obtained
(misfire) .
Defective primer.
See paragraph 46.
Failure to discharge un-
til after several percus-
sions on primer {primer
struck weakly).
(1) Firing rack and
hammer not working
freely.
(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 bars or roughened bearing
surfaces. Remove burs or
rough spots with crocus
cloth or oilstone. Clean off
dirt and gummy 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 discherge;
no percussion on primer
at all.
(1) Safety piece not in
firing position.
(2) Breechblock not
fully closed,
(3) Broken firing pin.
(1) Sot safety piece plunger
in the hole marked “Fire" or
“Tir."
(2) Close breechblock.
(3) Replace firing pin.
Failure to extract car-
tridge case.
Broken extractor.
See paragraph 45. Examine
the edge of the chamber for
bursordcformatlon. Replace
extractor.
Pawl falls to operate.
Broken pawl spring or
broken breechblock
latch spring.
If latch spring is broken, re-
place it. If pawl spring is
broken, replace breechblock
latch assembly.
Breechblock does not
rotate freely.
(1) Lack of lubrica-
tion.
(2) Burs or roughen-
ing of threads of breech-
block or breech recess.
(1) Remove block, clean
recess and threads with sol-
vent, wipe dry; coat lightly
with lubricating oil; reas-
semble.
(2) Remove and clean as In
(1) above. If burs or rough-
ness are found, the correction
must be made by ordnance
maintenance company.
Safety bolt does not re-
main in upper position
when coupler key is with-
drawn.
Weak or broken safe-
ty-bolt spring, or spring
and notch do not engage.
Replace safety-bolt assemb-
ly. If notch is deformed refer
to ordnance maintenance com-
pany for correction.
Safety bolt fails to rise
when coupler key is with-
drawn.
Safety- bolt lug is shorn
off.
Replace safety-bolt as-
sembly.
Note.— T he safety bolt can-
not rise when the breechblock
is closed; forcing out the cou-
pler key with the breech closed
results in shearing off the lug.
58
SERVICE OF THE PIECE
54-55
b. 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 will drop into the cam
groove and jam the block.
(3) In order to retract the gun for cleaning the slides
and roller paths, 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 x h 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.
■ 55. Miscellaneous Parts of Carriages. — a. Operations
common to both M1897 and M1897A4 carriages. — (1) The
exposed rocker segment (elevating rack) must be kept clean
and lubricated.
(2) The exposed sections of the axle must be kept clean
and lubricated. In travel they should be covered and blocked
to prevent traversing.
(3) The traversing mechanism should be checked for ex-
cessive lost motion. One-half turn of the handwheel is allow-
able. During traveling, the traversing handwheel should be
strapped to prevent its turning.
(4) The elevating mechanism should be protected from
vibration in travel by a strap or cable £o hold the breech
firmly on the traveling lug.
59
55
SERVICE OF THE PIECE
b. Operations pertaining to the M1897 carriage only. — (1)
Looseness in the wooden parts of the wheel is taken up by
periodic tightening of the hub bolts, which must be done at
least twice a year. Shrinkage of the wood may be retarded
by soaking the wood in raw linseed oil. Soaking the wheels
in water is ineffective, because the water quickly dries, leaving
the wood in worse condition than before.
(2) End play of the wheel is adjusted by placing leather
washers between the hub and the axle collar, and between
the hub and the axle cap. Until these become worn too thin,
a temporary adjustment may be made by placing the linch
pin in a shallower notch in the axle cap. If the linch pin is
placed initially in the deepest notch, two additional adjust-
ments are possible before new washers are needed.
c. Operations pertaining to the M1897A4 carriage only . —
(1) Tires must be maintained at a pressure of 25 pounds.
Treads are checked for excessive wear. Excessive wear will
result if the piece is not held in the center of traverse In
traveling. The amount of toe-in of the wheels can be ad-
justed by the ordnance maintenance company. Tires should
be removed at least once a year, and the disk and rim cleaned
and painted.
(2) The compensating shaft must be kept clean, oiled, and
covered in traveling.
(3) The brakes are adjusted by means of brake adjusting
wedges, which are turned clockwise to tighten. One or two
notches at a time are sufficient to take up looseness due to
the wear of the brake lining. The wheels should be jacked
up to check that the brakes do not drag when the levers
are in the “off” position. If the brakes; do not release
quickly, the retracting or compression springs may be
replaced.
(4) To eliminate excessive side play in the wheel bearings,
the carriage is jacked up, the hub cap removed, the cotter
pin extracted from the wheel spindle, and the adjusting nut
tightened, while the wheel is slowly rotated, until the wheel
binds. The nut is then backed off until the wheel rotates
freely but without side play. The cotter pin and hub cap
are then reassembled.
60
SERVICE OF THE PIECE
55-56
(5) The wheels, hubs, and brake drums should be removed
from the spindles every 2,000 miles, and at least twice yearly.
All grease should be removed from the hub cavities, and the
hub and inner and outer roller bearings washed clean with
solvent. After being dried the hub and bearings should be
packed with fresh, clean fiber wheel-bearing grease.
d. Automatic pole support on the Ml 91 8 limber . — The dis-
assembly 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. Mal-
functioning 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 sus-
pended 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.
e . Caisson band brake. — The brake mechanism is described
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 adjusting
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 “off’'
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.”
■ 56. Sighting Equipment. — a. General . — Except on the
range drum and the bracket fuze setter, battery personnel
is not permitted to disassemble or adjust this equipment,
but tests must be made before every firing to determine
whether the tolerance of error Is exceeded. If exceeded,
the fact is reported to the ordnance maintenance company.
In general, the sights are correct —
61
56
SERVICE OF THE PIECE
(1) In direction , If the deflection scales read plateau 0
drum 100 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 indicate the same angle above the horizontal that
is measured with an accurate gunner’s quadrant on the
tube.
(3) If there is no excessive lost motion between the sights
and the tube.
b. Testing equipment. — Equipment used in testing sights
consists of bore sights and a gunner’s quadrant. The target
for bore sighting may be a distant terrain object, more than
1,000 yards away, or a test target for use in close proximity.
In the latter case the displacement of the axis of sighting
from the axis of the bore must be correctly shown. For this
gun the sight displacement is 9.5 inches to the left of and
6.81 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, in which case leveling of the trunnions is
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. 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
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.
d. Collimator sight , M1901 , and mount , M1901* — -The fol-
lowing tests should be made:
(1) Test for trunnion friction (should be made first)
(a) Set any range and site. Do not change it during the
test.
(b) Center the site bubble by raising the breech with the
angle-of-site handwheel. If the bubble passes the center,
start over.
62
SERVICE OF THE PIECE
56
(c) Read the elevation of the tube with the gunner's
quadrant.
( d ) Throw off the site bubble by raising the breech, then
recenter bubble by lowering the breech. If the bubble passes
the center, start over.
( e ) Read the elevation again with the quadrant.
(/) The difference between the elevations read in (c) and
(e) above is the error due to trunnion friction. If the error
exceeds 1 mil, the trunnion bearings are examined, cleaned,
and lubricated, and the test repeated. If the error is still ex-
cessive, the piece should be repaired by the Ordnance
Department.
(2) Test of site bubble for elevation . — (a) Set range zero,
site zero. Do not change it during the test.
( b ) Center the site bubble by raising the breech with the
angle-of-site handwheel. If the bubble passes the center,
start over.
(c) Read the elevation of the tube with the gunner’s
quadrant.
(d) Throw off the site bubble by raising breech, then re-
center the bubble by lowering the breech. If the bubble
passes the center, start over.
(e) Read the elevation again with the quadrant.
(/) Take the mean of readings in ( c ) and (e) above.
Both readings should be close to zero. The mean must be
within 1 mil of zero. This test differs from the trunnion
friction test in that in the test the error of trunnion friction
is eliminated by taking the mean of the readings, thus
giving the error of the site bubble itself.
(3) Test of the collimator sight for direction. — (a) Center
the gun in the cradle. (Force a screw driver between the
sweeper plate and the wall of the slide; force the gun to the
opposite wall; make a fine vertical mark across the front
of the sweeper plate and the front of the cradle. Force the
gun on the opposite side with a screw driver. If the mark
on the sweeper plate does not agree with that of the cradle,
move the gun toward the middle by half the distance be-
tween the two marks.)
(b) Bore sight on the target.
63
56
SERVICE OF THE PIECE
(c) Starting near plateau 0 drum 200, turn the drum
until the vertical hair is on the target. If the hair passes
the target, start over. Record the reading.
(d) Starting near plateau 0 drum 0, turn the drum until
the vertical hair is again on target. If the hair passes the
target, start over. Record the reading.
( e ) The readings in ( c ) and (d) above should be be-
tween plateau 0 drum 104 and plateau 0 drum 96, both
inclusive, and should not differ by more than 5 mils. If
the sight has a greater error, it should be adjusted by the
Ordnance Department. Until adjusted apply a correction
to deflection settings.
(4) Test of collimator sight for elevation . — (a) Set the
range at zero.
(b) Bore sight on the target, using the angle-of-site
handwheel.
(c) Read the elevation of the tube with the gunner's
quadrant.
(d) Place the horizontal hair of the sight on the target
by lowering the breech, using the angle-of-site handwheel.
If the hair passes the target, start over.
(e) Read the elevation of the tube with the gunner's
quadrant.
(/) Repeat (d) above by raising the breech. If the hair
passes the target, start over.
( g ) Read the elevation of the tube with the gunner's
quadrant.
(h) Take the mean of (e) and (g) above. This mean
should not differ by more than 1 mil from reading in (c)
above.
e. Test of the range drum, — This is automatically tested
in test d (2) above. An individual test may be made as
follows:
(1) Set site and range scales at zero.
(2) Level the angle-of-site bubble with the angle-of site
handwheel.
(3) Test the tube with a gunner's quadrant. If the tube
is not horizontal, the range drum is in error. The correct
assembly of the range drum may be checked by inspection.
When set at zero , the index opposite the range rack scale
64
SERVICE OF THE PIECE
56
should also read zero. (For calibration purposes, the range
drum may have been assembled at an off-zero reading.)
/. Adjustment of the bracket fuze 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.