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V
UNCLASSIREO
WAR DEPARTMENT FIELD MANUAL
4
SERVICE OF THE PIECE
105-MM HOWITZER M2
TRUCK-DRAWN
and TRACTOR-DRAWN
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:r
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CD
WAR DEPARTMENT • OCTDBER 1945
UNCLASSIREO
h^tyofOOD dir, 5200. 1 R
*
WAR DEPARTMENT FIELD MANUAL
EM 6-75
This manual supersedes EM 6-75, 12 December 1941, including C 1,
23 May 1942; C 2, 29 June 1943; C 3, 3 September 1943; C 4, 15 Oc-
tober 1943; and C 5, 25 October 1944.
SERVICE OF THE PIECE
105-MM HOWITZER M2
TRUCK-DRAWN
and TRACTOR-DRAWN
WAR DEPARTMENT • OCTOBER 1945
'ISSEMINATION OF RESTRICTED MATTER.
No person is entitled solely by virtue of bis grade or position to knowledge
or possession of classified matteri Such matter is entrusted only to those
individuals whose official duties require such hnowledge or possession*
(See also paragraph 23b, AR 380-S, IS March 1944.)
United States Government Printing Office
Washington : 1945
WAR DEPARTMENT
Washington 25, D. C., 5 October 1945
FM 6-75, Service of the Piece, 105-mm Howitzer M2,
Truck-drawn and Tractor-drawn, is published for the infor-
mation and guidance of all concerned.
[AG 300.7 (25 Sep 45)]
By ORDER OF THE SECRETARY OF War:
Official: G. C. MARSHALL
EDWARD F. WITSELL Chiej of Staff
Major General
Acting The Adjutant General
Distribution:
AAF (5); AGE (40); ASF (2); Arm & Sv Bd (i);
PG 9 (2); Gen & Sp Sv Sch (2) except 6 (500);
USMA (5); RTC 6 (100); A (2); CHQ (2); D (5)
except I (o); B 6 (2); R 6 (2). T/O & E: 6-26 (25);
6-26-OS (25); Special distribution.
Refer to FM 21-6 for explanation of distribution formula.
II
CONTENTS
Para'
graphs Page
CHAPTER 1. GENERAL 1-3 1
CHAPTER 2. ORGANIZATION 4-5 4
CHAPTER 3. POSTS: MOUNTING AND DIS-
MOUNTING 6-11 6
CHAPTER 4. MOVEMENTS OF PIECES BY 12
HAND 12-13
CHAPTER 5. UNCOUPLING AND COUPLING . . 14-15 13
CHAPTER 6. PREPARE FOR ACTION AND
MARCH ORDER 16-18 16
CHAPTER 7. DUTIES IN FIRING.
Section I. Indirect laying 1^28 26
II. Direct laying 29-33 43
CHAPTER 8. ADDITIONAL INFORMATION ON
SERVICE OF THE PIECE 34-44 53
CHAPTER 9. CARE AND ADJUSTMENT OF
SIGHTING AND FIRE-CONTROL
EQUIPMENT 45-47 58
CHAPTER 10. SECTION MAINTENANCE DRILL. 48-54 64
CHAPTER 11. DECONTAMINATION AND DE-
STRUCTION OF EQUIPMENT.
Section I. Decontamination 55-57 90
II. Destruction 58-63 90
INDEX 95
III
I
IV
Figure i, loymm howitzer M 2 A 1 and truck., zVi'ton, 6x6.
This manual supersedes FM 6—y^, 12 December 1941, including C i,
2^ May 1942; C 2, 29 June 1943; C 3, 3 September 1943: C 4, 13
October 1943; and C 3, 23 October 1944.
CHAPTER 1
GENERAL
1 . PURPOSE AND SCOPE. This manual prescribes the
duties to be performed in the service of the piece by the
personnel normally assigned to one howitzer section of the
firing battery.
2 . REFERENCES, a. Description, operation, func-
tioning, and care of materiel, (i) Howitzer. TM
9-325; SNL C-21.
(2) Truc\. TM 9-801; SNL G-508.
(3) Tractor.. .TM 9-786; SNL G-162.
b. Description and operation of fire control and
sighting equipment. TM 9-325; SNL F-i.
c. Ammunition, TM 9-325, 9-1900, 9-1901; SNL R-i.
d. Cleaning and preserving materials. TM 9-850;
SNL K-i.
e. Vehicle driver. FM 25-10; TM 21-300; TM 21-301;
TM 21-305.
f. Maneuvers of battery. FM 6-101.
g. Safety precautions in firing. AR 750-10; FM 6-40;
FM 6-140 (when published).
h. Firing battery. FM 6-140.
i. Gunnery. FM 6-40.
j. Reconnaissance, occupation, and organization of
position. FM 6-101; FM 6-140,
Note. For military terms not defined in this manual, see TM 20-205;
for list of training publications, see FM 21-6; for training films, film
strips, and film bulletins, see FM 21—7; for training aids, see FM 21-8.
1
2
3. DEFINITIONS AND TERMS, a. Section. Tables
of Organization and Equipment prescribe the personnel and
material comprising a section of a battery. In this manual,
the term is often used to designate the personnel required
to serve one piece and the materiel of the section. In a
restricted sense, the term section may be used to designate
only the personnel of a section.
b. Coupled. A piece is said to be coupled when its
lunette is attached to the pintle of its prime mover. (See
figs. I and 2.)
c. Uncoupled. A piece is uncoupled when its lunette
is detached from the pintle of its prime mover.
d. Front. The front in a section, pieces coupled, is the
direction in which the prime mover is headed; pieces un-
coupled, the front is the direction in which the muzzle
points. However, for determining the right or left of the
piece, coupled or uncoupled, the front is the direction in
which the muzzle points.
e. Right (left). The direction right {left) is the right
{left) of one facing the front.
f. In battery. A howitzer is said to be in battery when
its tube is in normal firing position.
3
CHAPTER 2
ORGANIZATION
4 . COMPOSITION, a. Howitzer section. A howitzer
section consists of a chief of section, a howitzer squad, and
a driver. Any additional cannoneers (assigned or attached)
act as reliefs or are assigned to other duties as the chief of
section may direct. When the section uncouples for drill or
for firing, the chief of section remains at the position of the
piece and commands the howitzer squad.
b. Howitzer squad. The gunner and seven cannoneers
numbered from i to 7, who serve the piece, are for purposes
of convenience referred to as the howitzer squad.
c. Ammunition section. The ammunition section con-
sists of the chief of section, machine gun personnel, ammuni-
tion handlers, and the drivers of the ammunition vehicles of
the ammunition (fifth) section.
5 . FORMATION, a. Order of formation. A howitzer
squad is formed as shown in figure 3. Higher-numbered
cannoneers, if present, form in order on the left of No. 7.
b. To form, (i) The place of formation is indicated
and the commands given thus, for example: i. in front
(rear) of your pieces, or i. on the road facing the park,
2. FALL IN. Each gunner repeats the command fall in
4
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 in double time and assemble at attention in
their proper places. For the first formation of the howitzer
squads for any drill or exercises, the caution, “As howitzer
squads,” precedes the command. The chief of section, if
present, supervises the formation.
(2) In case the front or rear of the piece is designated, each
squad falls in at its post (par. 6 ).
c. To call off. (i) The command is: CALL OFF.
The cannoneer on the left of the gunner calls off “One”;
the cannoneer on the left of No. i, “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.
5
CHAPTER 3
POSTS: MOUNTING AND DISMOUNTING
6. PQSTS OF HOWITZER SQUADS, a. Pieces
coupled, (i) In front of piece. The squad is in line
facing to the front, its center 2 paces from the front of the
prime mover.
(2) In rear of piece. The squad is in line facing to the
front, its center 2 paces from the muzzle of the piece.
b. Pieces uncoupled. In rear of piece. The squad is
in line facing to the front, its center 2 paces from the end
of the trails.
7 . TO POST HOWITZER SQUADS. The squads, hav-
ing been marched to the vicinity of the pieces, are posted at
the command SQUADS in front (rear) of your pieces. Each
gunner marches his squad to its piece and posts it in the
position indicated.
8. POSTS OF CANNONEERS, a. Pieces coupled.
The cannoneers of the howitzer squad are posted as shown
in figure 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. Pieces uncoupled. See paragraph 17 and figures 10
and II.
9 . TO POST CANNONEERS, a. The commands are:
I. cannoneers, 2. POSTS. Each gunner repeats the com-
mand POSTS. The cannoneers move in double time to their
posts.
b. For preliminary instruction, the squads on ' entering
the park are first posted with their pieces, and cannoneers
are then sent to their posts by the foregoing command. The
command is general, however, and is applicable when the
cannoneers are in or out of ranks, at a halt or marching, and
when the pieces are coupled or uncoupled.
6
Figure 4. Posts of cannoneers, howitzer coupled.
7
10 . TO MOUNT. a. The commands are: i. cannon-
eers, PREPARE TO MOUNT, 2 . MOUNT.
(1) When a truc\ is used as prime mover. At the first
command, cannoneers move in double time to positions
shown in figure 4. At the second command, each cannoneer
at the right rear of the truck will, in turn, place his right
foot on the right rear bumper and, grasping the step on the
tail gate with his right hand, will swing his left leg over the
gate into the body of the truck. Each cannoneer on the left
will place his left foot on the left rear bumper and, grasping
the step with his left hand, will swing his right leg over the
gate into the body of the truck. The cannoneers take seats
as indicated in figure 5. If the chief of section and driver
are to be included in the movement, the commands are: i.
PREPARE TO MOUNT, 2. MOUNT. At the first command, the
driver and chief of section take position on the left and right
of the rear of the truck, respectively. After the last can-
noneer has mounted, the driver fastens the safety strap; the
chief of section and driver mount, take seats, and close their
doors.
(2) When medium tractor M5 is used as prime mover.
At the first command, the driver takes position directly in
front of the right door, opens it, and faces to the rear holding
the door. The chief of section opens the left door and takes
position 4 feet in front of it facing to the rear. At the second
command, the gunner and cannoneers Nos. i to 6, inclusive,
on their respective sides, will in turn step on the footrest on
the bumper and grasp the hand grips located on the body of
the tractor (or the grips on the windshield when down).
They will then step up into the body of the tractor and take
seats as indicated in figure 6. The gunner closes the right
door and the chief of section the left door when all personnel
are seated. Cannoneer No. 7 moves double time to the
executive’s truck and mounts. If the chief of section and
driver are to be included in the movement, the commands
are: i. prepare to mount, 2. MOUNT.
b. If the commands are: i. cannoneers, 2. MOUNT,
the cannoneers execute, at the command mount, all that has
been prescribed for the commands cannoneers, prepare to
8
Figure 5 . Posts of cannoneers mounted in truc\.
9
MOUNT and mount. If all personnel of the section are to be
included in this movement, the command is: MOUNT.
11 . TO DISMOUNT, a. The commands are: cannon-
eers, PREPARE TO DISMOUNT, 2. DISMOUNT. At the first
command, cannoneers assume positions from which they
can dismount promptly; at the second command, they jump
to the ground and take their posts in double time. If the
chief of section and driver are to be included in this move-
ment, the commands are: i. prepare to dismount, 2.
DISMOUNT.
b. If the commands are: i. cannoneers, 2. DISMOUNT,
the cannoneers execute, at the command dismount, all that
has been prescribed for the commands cannoneers, prepare
TO dismount and dismount. If the chief of section and
driver are to be included in this movement, the command is:
DISMOUNT.
11
CHAPTER 4
MOVEMENTS OF PIECES BY HAND
12 . COUPLED. Lhe pieces are not moved by hand when
coupled.
13. UNCOUPLED, a. The commands are: i. pieces
FORWARD (backward), 2. MARCH. At the first command,
the gunner and No. i remove the trail lock pins and place
them in the traveling positions. Nos. 2 and 6 on the left
trail and Nos. 3 and 7 on the right trail manipulate the trails
as directed by No. 4 so that the axle locks may be locked by
Nos. 4 and 5, working on the left and right, respectively.
Nos. 2, 3, 6, and 7 close the trails, and No. 6, assisted by
No. 7, fastens the trail lock. Nos. 4 and 5 release the hand
brakes. Nos. 2 and 6 and Nos. 3 and 7 then grasp the trail
handles on the left and right, respectively. No. 4 grasps the
left wheel. No. 5 the right wheel. The gunner and No. i
place themselves 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. If the situation requires
additional manpower. Nos. 4 and 5, under the direction of
the chief of section, will obtain ropes from section equip-
ment in the prime mover and attach them to the hooks on
the left and right axles, respectively. Personnel designated
by the battery executive to assist in the movement of the
piece will take position and pull on the ropes as directed by
the chief of section.
b. At the command march, all move the piece forward
(backward) under the direction of the chief of section.
When the piece is being moved up or down steep slopes.
Nos. 4 and 5 assist by alternately setting and releasing the
left and right brakes, thus permitting the piece to be
pivoted about the alternately locked wheels. At the com-
mand HALT, the piece is stopped and reestablished in the
firing position; all resume their posts (par. 17).
12
CHAPTER 5
UNCOUPLING AND COUPLING
14 . UNCOUPLING (fig. 7). a. General. At drills,
prime movers are posted as directed by the battery com-
mander. In combat and in instruction simulating it, the
prime movers are conducted by the first sergeant to a place
previously designated by the battery commander; there they
are disposed so as to take the best advantage of cover and
concealment. If no cover and concealment are available,
the prime movers are located in rear of either flank, faced
to the front, with wide intervals between them.
b. To fire to front. The command is: ACTION
FRONT. If marching, the prime movers halt at the com-
mand or signal. The cannoneers, if mounted, dismount
after the prime movers have halted.
(i) Pieces. The gunner and No. i hasten to the wheels
nearest their respective posts. Nos. 2, 3, 6, and 7 hasten to
the trail handles, even-numbered cannoneers on the right,
odd-numbered on the left. Nos. 4 and 5 go to the muzzle of
the piece and assist by placing their weight on the tube. No.
2 unlatches the pintle and, assisted by Nos. 3, 6, and 7, raises
the trails from the pintle; No. 4 sets the left hand brake.
Nos. 2, 3, 4, 5, 6, and 7 swing the piece 180° clockwise. Dur-
ing this operation. No. 3 releases the drawbar lock and turns
the drawbar 180°, latching it in the firing position. Nos. 2,
3, 6, and 7 then lower the trails to the ground. No. 5 sets the
right hand brake. The gunner and all cannoneers then
unload the ammunition, tools, and accessories and arrange
them in an orderly and convenient manner to the left of the
piece (when the truck is used as the prime mover, the driver
lowers the tail gate prior to the unloading). When the un-
loading has been completed, the chief of section commands
or signals drive on. The cannoneers take their posts (par.
17 and fig. 10).
BRono"— 45 2
13
14
, ip.) Prime movers. At the command drive on, the prime
movers move out and are conducted by the first sergeant to
their previously designated position.
c. To fire to rear. The command is; ACTION REAR.
The movement is executed according to the principles of
ACTION FRONT. The piece is not turned after uncoupling.
d. To fire to flank. The command is: ACTION
RIGHT (LEFT). The movement is executed according to
the principles of action front, with the following modifica-
tions: after the piece is uncoupled, 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 prime mover;
articles unloaded from tbe prime mover are placed on tbe
ground so as to clear the track made by the prime mover.
15 . COUPLING, a. The pieces being in position and in
march order, the command is: COUPLE. The prime mov-
ers, under the command of the first sergeant, approach the
position from the right (left) flank. As each prime mover
approaches its piece, it turns to the left (right) and halts in
prolongation of the trails of the piece.
b. All cannoneers working together under the direction
of the chief of section load the tools, accessories, and unex-
pended ammunition. Nos. 2, 3, 6, and 7 hasten to the trail
handles, even-numbered cannoneers on the left, odd-
numbered on the right. Nos. 4 and 5 hasten to the front of
the piece and release the brakes. The prime mover, upon
signal from the chief of section, is maneuvered backward
until the pintle is almost over the lunette. Nos. 2, 3, 6, and
7 then raise the trails and, after No. 3 has placed the drawbar
in traveling position, place the lunette over the pintle. No. 2
latching the pintle. Nos. 4 and 5 assist by placing their
weight on the tube. All cannoneers take their posts (fig. 4).
15
CHAPTER 6
PREPARE FOR ACTION AND MARCH
ORDER
16 . TO PREPARE FOR ACTION (figs. 8 and 9.) a.
The piece being in position uncoupled, the command is;
PREPARE FOR ACTION. Duties of individuals are as
follows (on completion of his duties, each cannoneer takes
his post (fig. It)):
( 1 ) Chief of section, (a) Supervises the work of the can-
noneers.
{b) Inspects the materiel; verifies the fact that the recoil
mechanism contains the proper amount of oil and that all is
in order; and, when the operations have been completed, re-
ports to the executive, “Sir, No. (so-and-so) in order,” or
reports any defects that the section cannot remedy without
delay.
(2) Gunner, (a) Assisted by No. i, removes the breech
end of the howitzer cover.
(Z>) Removes the panoramic telescope from its case and
seats it in the telescope mount.
(c) Places the left trail lock pin in the firing position.
(d) Uncovers the telescope mount bubbles; sets the index
of the rotating head at zero, the deflection at zero, and centers
both bubbles.
(3) No. I. (a) Assists the gunner in removing the breech
end of the howitzer cover, throwing the cover to the right of
the right wheel.
(b) Places the right trail lock pin in the firing position.
(c) Operates elevating handwheel to assist No. 4 in unlock-
ing cradle lock.
(d) Uncovers the range quadrant bubbles; sets site 300 and
centers the bubbles.
(e) Operates the breech mechanism and examines the
breechblock, chamber, and bore, cleaning any parts requiring
it; leaves the breech open.
16
17
Figure 8. Squad preparing jor action, before trails are spread.
(/) When so directed by the executive, removes the elbow
telescope from its case and seats it in its mount.
(4) No. 2. (a) Spreads the left trail, assisted by No. 6,
when No. 4 calls “Spread.”
{b) Removes the rammer staff from its traveling position,
assembles it to the rammer (bore brush), and places it to the
right of the piece.
(c) When so directed, assists No. i in cleaning the breech
mechanism, chamber, and bore of the howitzer.
(d) Folds the muzzle and breech ends of the howitzer
cover and places them on the ground to the right of the right
wheel of the howitzer.
(5) No. (a) Spreads the right trail, assisted by No. 7,
when No. 4 calls “Spread.”
(b) Arranges the ammunition and tools, assisted by Nos.
4, 5, 6, and 7.
(c) Obtains the fuze setter from the section chest, and
places it convenient to the position of the ammunition.
(6) No. 4. (a) Unlocks and lowers bottom' shield flap,
assisted by No. 5.
{b) Unlocks the left axle lock from the traveling position
and latches it in the firing position; when he sees that both
axle locks are unlocked, calls “Spread,” to inform Nos. 2 and
3 that trails may be spread.
(c) Releases the left hand brake momentarily while trails
are being spread.
(d) Unlocks the cradle lock, assisted by the operation of
the elevating handwheel by No. i, and latches it in the firing
position.
(e) Removes the muzzle end of the howitzer cover, as-
sisted by No. 5.
(/) Assists No. 3 in arranging the ammunition and tools.
(7) No. 5. («) Assists No. 4 in unlocking and lowering
bottom shield flap.
(b) Unlocks the right axle lock from the traveling position
and latches it in the firing position.
(c) Releases the right hand brake momentarily while
trails are being spread.
19
Assists No. 4 to remove the muzzle end of the
howitzer cover and throws it on the ground to the right of
the right wheel.
(e) When directed by the chief of section, removes the
aiming posts from the traveling position, assembles them, and
sets them, out.
(/) Assists No. 3 in arranging ammunition and tools.
(8) No. 6 . (a) Unlocks the trail lock.
(^) Removes the trail handspike from its traveling posi-
tion and places it in its socket on the left trail.
(c) Assists No. 2 in spreading the left trail.
((f) Assisted by No. 7, places the section chest immedi-
ately to the left of the piece.
(e) Assists No. 3 in arranging the ammunition and tools.
(/) Distributes waste to the cannoneers.
(9) No. 7. (a) Assists No. 3 to spread the right trail.
{b) Assists No. 6 to place the section chest to the left of
the piece.
(c) Assists No. 3 in arranging the ammunition and tools.
b. If PREPARE FOR ACTION has not been ordered before
the piece is established in the firing position, the command
is habitually given by the chief of section as soon as the
piece has been uncoupled. If this is not desired, the caution,
“Do not prepare for action,” must be given.
17. POSTS OF CANNONEERS, PIECE UNCOU-
PLED. a. The piece having been uncoupled but not pre-
pared for action, posts of cannoneers are as in figure 10.
b. The piece having been uncoupled and prepared for
action, posts are taken as follows (fig. ii) :
(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 between
the trail spades and on line with them.
(2) Gunner. Immediately behind the left wheel and out-
side the trail.
(3) No. I. Immediately behind the right wheel and
outside the trail.
20
Figure lo. Posts of cannoneers, howitzer uncoupled but not prepared
for action.
(4) No. 2. Three feet in rear of the gunner, covering
him, and inside the trail.
(5) No. j. Two feet to the left of No. 2.
(6) No. 4. Two feet in rear of No. 3, covering him.
(7) No. 5. Two feet to the left of No. 4.
(8) No. 6 . Two feet to the left of No. 5.
(9) No. 7. Two feet in rear of No. 5, covering him.
C. At drill, all stand at attention at their posts facing the
front. In firing and combat, minor modifications of these
posts are required for the more efficient performance of the
duties in the service of the piece and for protection of the
personnel. Higher-numbered cannoneers, if present, take
posts as prescribed by the chief of section.
Figure ii. Posts of cannoneers, howitzer prepared for action.
d. 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 will be rotated
frequently in a manner to provide progressive instruction.
In addition, the chief of section should make such individual
changes as necessary during drill to assure that each can-
noneer is thoroughly trained in the duties of two or more
lower-numbered posts.
22
18. MARCH ORDER, a. To resume order for march-
ing. The howitzer being uncoupled and prepared for
action, to resume the order for marching, the command is;
MARCH ORDER. Duties of individuals are as follows (on
completion of his duties, each cannoneer takes his post (fig.
lo)):
(1) Chief of section, (a) Supervises the work of the can-
noneers.
(h) Inspects the materiel; makes sure that the piece is not
loaded and that the trail lock and cradle lock are locked in
the traveling position; and, when the operations have been
completed, reports to the executive, “Sir, No. (so-and-so) in
order,” or reports any defects which the section cannot rem-
edy without delay.
(2) Gunner, (a) Places the piece in the center of traverse.
(h) Removes left trail lock pin from the firing position and
places it in the traveling position.
(c) Sets the rotating head and deflection at zero and closes
the covers on the telescope mount level bubbles.
(d) Removes the telescope from the mount, returns it to
its case, and locks the case.
(e) Replaces the breech end of the howitzer cover, assisted
by No. I. J
(3) No. I. (a) Closes the covers over the range quadrant
bubbles.
(b) Operates elevating handwheel to assist No. 4 in lock-
ing cradle lock.
(c) Removes the right trail lock pin from the firing posi-
tion and places it in the traveling position.
(d) Inspects the chamber to see that piece is unloaded
and closes breech.
(e) Removes the elbow telescope, if mounted, from its
mount and returns it to its case.
(/) Assists the gunner in replacing the breech end of
the howitzer cover.
(4) No. 2. (a) Closes the left trail, assisted by No. 6,
after No. 4 has called “Close.”
(i>). Disassembles the rammer staffs; removes the rammer
(bore brush) and places it in the section chest; secures the
rammer staff in its traveling position on the trail.
23
(5) No. (a) Closes the right trail, assisted by No. 7,
after No. 4 has called “Close.”
(i>) Places the fuze setter in the section chest.
(c) Prepares ammunition and tools, assisted by Nos. 4,
5, 6, and 7, for'loading in the prime mover.
(6) No. 4. (a) Locks the cradle lock in the traveling
position, assisted by the operation of the elevating hand-
wheel by No. I. When the cradle lock has been locked,
calls “Close” to inform Nos. 2 and 3 that trails may be closed.
(b) Locks the left axle lock in the traveling position.
(c) Raises and latches the bottom shield flap, assisted by
No. 5.
(d) Replaces the muzzle end of the howitzer cover, as-
sisted by No. 5.
(e) Assists No. 3 in preparing the ammunition and tools
for loading in the prime mover.
(7) No. 5. (a) Locks the right axle lock in the traveling
position.
(b) Assists No. 4 in raising and latching the bottom shield
flap.
(c) Assists No. 4 in replacing the muzzle end of the
howitzer cover.
(d) Procures, disassembles, and replaces the aiming posts
in covers. Secures the aiming posts in the traveling position
on the trail.
(e) Assists No. 3 in preparing the ammunition and tools
for loading in the prime mover.
(S) No. 6. (a) Assists No. 2 in closing the left trail.
(b) Assisted by No. 7, locks the trail lock.
(c) Removes the trail handspike from the left trail and
secures it in its traveling position.
(d) Prepares the section chest for loading in the prime
mover, assisted by No. 7.
(e) Assists No. 3 in preparing the ammunition and tools
for loading in the prime mover.
(9) No. 7. (a) Assists No. 3 in closing the right trail.
(b) Assists No. 6 in locking the trail lock.
(c) Assists No. 6 in preparing the section chest for load-
ing in the prime mover.
24
{d) Assists No. 3 in preparing the ammunition and tools
for loading in the prime mover.
b. To resume fire in another position, (i) If firing
is to be resumed shortly in another position to which the
piece must be towed by its prime mover, the command
MARCH ORDER is not given. In this case, at the command
for coupling, 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 piece
is coupled, the operations pertaining to march order are
completed.
25
CHAPTER 7
DUTIES IN FIRING
Section I. INDIRECT LAYING
19 - GENERAL. In general, the duties in firing are as
follows (see figs. 12 through 16):
a. The chief of section is responsible that all duties are
properly performed, all commands executed, and all safety
precautions observed.
b. The gunner sets the announced deflection, lays for direc-
tion, and refers the piece.
c. No. I sets the announced site and elevation, opens and
closes the breech, and fires the piece.
d. No. 2 loads the piece.
e. No. 3 operates the fuze setter and makes the proper
setting of fuzes.
Figure 12. Preparing ammunition.
26
Figure ij. Setting time fuze.
Figure i6. Piece loaded and ready to fire.
/. No. 4 assists No. 3 in setting fuzes, and passes the rounds
to No. 2 for loading.
g. No. 5, assisted by Nos. 6 and 7, prepares charges and
passes the assembled round to No. 4.
h. Nos. 6 and 7 remove ammunition from the containers
and assist No. 5 in preparing charges and assembling rounds.
No. 7 keeps empty cartridge cases out of way of the
cannoneers.
20. CHIEF OF SECTION, a. Enumeration of duties,
(i) To lay for elevation, assisted by No. i, when the
gunner’s quadrant is used.
(2) To measure the elevation (range).
(3) To measure the site to the mask.
(4) To indicate to the gunner the aiming point.
(5) To follow fire commands.
(6) To indicate when the piece is ready to fire.
(7) To give the command to fire.
(8) To report errors and other unusual incidents of fire
to the executive.
(9) To conduct prearranged fires.
(10) To record basic data.
(11) To observe and check frequently the functioning of
the materiel.
(12) To assign duties when firing with reduced personnel.
(13) To check, before they are replaced in their con-
tainers, all rounds not fired which have been prepared for
firing.
b. Detailed description of duties, (i) To lay for
elevation when gunner s quadrant is used. («) The com-
mand QUADRANT (SO MUCH) indicates that the gunner’s quad-
rant is to be used.
{b) To set an elevation on the gunner’s quadrant (fig. 17),
for example, 254.5 nails, the chief of section sets the upper
edge of the index plate opposite the 250 mark of the gradu-
ated arc on the quadrant frame and turns the micrometer
on the index arm to a reading of 4.5. Care must be taken
to face the same side of the quadrant in setting both the
index plate and the micrometer knob.
669119 °— 45 -
•3
29
(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, with the words “line of fire” at the bottom and
the arrow pointing toward the muzzle. The chief of sec-
tion 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 to the left of the breech, places his eye squarely
Figure 17. Setting the gunner's quadrant.
opposite the side of the quadrant, and holds the quadrant
firmly on the quadrant seat, parallel to the axis of the bore.
He must hold the quadrant in the same manner for each
subsequent setting, and view the quadrant bubble from a
point directly opposite to it.
{d) No. I operates the elevating handwheel until the
bubble is centered, making sure that the last movement is in
the direction in which it is most difficult to turn the hand-
wheel. The chief of section warns No. i when the bubble
30
is approaching the center, in order that the final centering
may be performed accurately.
(2) To measure elevation. At the command measure
THE ELEVATION, the piece having been laid, the chief of sec-
tion causes No. i to set site 300 and, with the range drum
knob, to center the range quadrant longitudinal level bubble.
The chief of section then reads the elevation set on the eleva-
tion scale and announces the elevation thus set; for example,
“Elevation No. (so-and-so), (so much).”
(3) To measure site to the mas\. {a) The command is:
MEASURE THE SITE TO THE MASK. The chief of
section has No. i set site 300 on the angle of site scale and
center the cross level bubble. Then, sighting along the
lowest element of the bore, he causes No. i to operate the
elevating mechanism until the line of sight just clears the
crest at its highest point in the probable field of fire. He
causes No. i to center the longitudinal level bubble by turn-
ing the range drum knob. He reads the desired site from
the elevation scale and micrometer and reports it to the execu-
tive thus: “Site No. (so-and-so), (so much).”
{b) When the executive announces the minimum quad-
rant elevation or the minimum elevation, charge, and site,
the chief of section records it in a notebook and causes No. i
to chalk the minimum elevation for each charge to be used
on a convenient place on the shield.
(4) To indicate to gunner the aiming point. Whenever
an aiming point has been designated by the executive, the
chief of section will make sure that he has properly identified
the point in question. He will then indicate it to the gunner.
If there is any possibility of misunderstanding, the chief of
section will turn the telescope until the horizontal and vertical
hairs are on the point designated.
(5) To follow fire commands. The chief of section will
follow fire commands mentally. He will not repeat the com-
mands 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 piece is ready to fire. When the ex-
ecutive can see arm signals of the chief of section, the chief
of section will extend his right arm vertically upward as a
signal that the piece is ready to fire. He gives the signal as
31
soon as the gunner calls “Ready.” When arm signals can-
not be seen, the chief of section reports orally to the executive,
“No. (so-and-so) ready.”
(7) command to fire. When No. i can see arm
signals made by the chief of section, the chief of section will
give the command to fire by dropping his right arm sharply
to his side. When his arm signals cannot be seen, he orally
commands: NO. (SO-AND-SO) FIRE. He will require the
cannoneers to stand clear of the recoil of the piece.
(8) To report errors and other unusual incidents of fire
to the executive. If the piece cannot be fired, the chief of
section will promptly report that fact to the executive, and
the reason; 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 at once report that
fact with the amount of error; for example, “No. (so-and-so)
fired too mils right.” Whenever the gunner reports that the
aiming posts are out of alignment with the telescope due to
displacement of the piece, the chief of section, at the earliest
convenience, will request permission from the executive to
realign the aiming posts. Likewise, he will promptly report
other unusual incidents that affect the service of the piece.
(See par. 37.)
(9) To conduct prearranged fires. Whenever the execu-
tion of prearranged fires is ordered, the chief of section will
conduct the fire of his section in strict conformity with the
prescribed data.
(10) To record basic data. The chief of section will re-
cord in a notebook data of a semipermanent nature. These
include such data as minimum' elevations; base deflections,
including aiming points used; prearranged fires when pre-
pared schedules are not furnished; safety limits in elevation
and deflection; number of rounds fired, with the date and
hour; and calibration corrections and standing corrections
when appropriate.
(11) To observe and chec\ functioning of materiel. The
chief of section closely observes the functioning of all parts
of the materiel during firing. Before the piece is fired, he
makes sure that the recoil mechanism contains the proper
amount of oil; thereafter he carefully observes the function-
32
ing of the recoil system. He promptly reports to the execu-
tive any evidence of trouble.
(12) To assign duties when firing with reduced personnel.
whenever the personnel of the section serving the piece is
temporarily reduced in numbers below that indicated in
this manual, the chief of section will make such redistribu-
tion of duties as will best facilitate the service of the piece.
(13) To chec\, before replaced in their containers, all
rounds not fired which have been prepared for firing. The
chief of section personally checks, before they are replaced
in their containers, all rounds not fired which have been pre-
pared for firing, to see that all seven increments are present
in proper condition, that they are assembled in the proper
numerical order, and that they are of the proper lot number.
He also checks to see that the lot number on the ammunition
corresponds to the lot number on the container. He obtains
a slip of paper on which an officer of the battery has certified
with his initials that all required precautions as to checking
increments have been taken, and gives it to No. 6 for inclu-
sion under the seal when unused ammunition is replaced
in containers and sealed.
21 . GUNNER, a. Enumeration of duties, (i) To
center the bubbles on the telescope mount.
fa) To set or change the deflection.
(3) To apply the deflection difference.
(4) To lay for direction.
(5) To call “Ready.”
(6) To refer the piece.
(7) To record base deflection.
(8) To measure a deflection.
(9) To make corrections for aiming post displacement.
b. Detailed description of certain duties, (i) To
set or change deflection. («) To set deflection. At the com-
mand, for example, deflection 483, the gunner first sets the
azimuth micrometer index (movable) to its zero position
and zeros the azimuth micrometer if it is not already so set.
Using his left hand, he pushes the throw-out lever, and with
his right hand turns the rotating head until the numeral 4
on the azimuth scale appears opposite the azimuth scale index.
33
He then grasps the azimuth worm knoh with his right thumb
and forefinger and turns the knob clockwise until the numeral
83 on the azimuth micrometer appears opposite the azimuth
micrometer index (movable). The gunner now turns the
azimuth micrometer index (movable) opposite an even ten
graduation on the micrometer in preparation for setting off
the next shift. This last movement does not change the set-
ting of the azimuth scales.
{b') To change deflection. The gunner should be trained
to grasp the azimuth worm knob with his right thumb and
forefinger. He also should be taught that moving his thumb
upward (clockwise) will cause the deflection to increase, and
the tube must be traversed to the left to bring the line of
sight back on the aiming point or aiming posts. Similarly,
he should be taught that moving his thumb downward
(counterclockwise) causes the deflection to decrease and re-
sults in a right shift in the tube when the weapon is relaid.
The deflection having been set at 483 mils, if a subsequent
shift of RIGHT 55 is Commanded, the gunner moves his right
thumb downward (counterclockwise) on the azimuth worm
knob until the deflection is decreased 55 mils. If the gunner
had set the azimuth micrometer index (movable) opposite
80 on the micrometer before the deflection change was given,
the numeral 25 would appear opposite the azimuth microm-
eter index '(movable) after the change. However, the true'
reading on the azimuth scale is obtained by turning the
movable index back to its zero position and noting the read-
ing on the scales, in this case (483 mils ~55 mils) 428 mils.
The azimuth micrometer index (movable) permits the gun-
ner to start from an even ten graduation each time a shift is
given. The gunner, having set off right 55, would move the
azimuth micrometer index (movable) opposite 20 or 30 on
the micrometer in preparation for the next shift. Should
the command be left (so much), the gunner changes the
setting by moving his thumb upward (clockwise) on the azi-
muth worm knob, thus increasing the deflection.
(2) To apply deflection diflerence. («) The command is:
ON NO. (SO-AND-SO) OPEN (CLOSE) (SO MUCH).
The gunner of the piece indicated in the command does not
change the deflection set on his telescope. Each of the other
34
gunners changes his deflection setting by the number of mils
specified in the command if his piece is next in line to the
piece indicated; by twice this number of mils if his piece is
second in line from the piece indicated; by three times this
number of mils if his piece is third in line from the piece
indicated.
{b) If the command is, for example, on no. 2 open 5, the
gunner on No. 2 makes no change; the gunner on No. i
turns the azimuth worm knob by moving his right thumb
downward (counterclockwise) to decrease his setting 5 mils;
the gunner on No. 3 moves his thumb upward (clockwise)
to increase his setting 5 mils; and the gunner on No. 4 moves
his thumb upward until the deflection is increased 10 mils
(twice the number of mils specified in the command).
(c) Should the command be, for example, on no. 3 close
10, the gunner on No. 3 does not change his setting; the
gunner on No. i moves his right thumb upward until his
deflection setting has been increased 20 mils; the gunner
on No. 2 moves his thumb upward until 10 mils have been
added to the deflection; and the gunner on No. 4 moves his
thumb downward until the setting has decreased 10 mils.
{d) When a deflection change and a deflection difference
are announced at the same time (for example, right 3 o, on
NO. I CLOSE 5), both of which affect the gunner’s piece, he
should first set off the deflection change and then apply the
deflection difference.
(e) In the methods described above, it is implied that the
gunner resets the azimuth micrometer index (movable) op-
posite an even ten graduation each time the azimuth worm
knob has been turned. This facilitates setting off the tens
and units on the azimuth micrometer scales. The gunner,
before turning the azimuth worm knob, should verify that
the movable index coincides exactly with the even ten gradu-
ation he has chosen.
(3) To lay jor direction, (a) The deflection having been
set, the gunner brings the vertical hair of the panoramic
telescope on the aiming point by traversing the piece. If
the amount of movement necessary is greater than can be
obtained by traversing, the trails must be shifted. To have
the trails shifted, the gunner commands or signals: MUZ-
35
ZLE RIGHT (LEFT). Nos. 2 and 6 on the left trail hand-
spike and Nos. 3 and 7 on the drawbar on the right trail
then shift the trails so that the muzzle moves in the indi-
cated direction. They stop shifting when commanded or
signaled to stop by the gunner. The gunner completes the
laying by centering the cross-level bubble on the telescope
mount and by traversing the piece until the vertical hair in
the telescope is on the aiming point while the cross level
bubble is exactly centered.
{b) To take up lost motion and improve the accuracy of
laying, the final movement of the traversing handwheel
should be such as to cause the vertical hair of the telescope
to approach the aiming point from the left. The gunner
should habitually lay with the vertical hair of the telescope
on exactly the same portion of the aiming point or target
and should insure that at the same time the cross level bubble
is centered.
(4) To Call "Ready.” The piece having been laid for
direction and No. i having called “Set,” the gunner verifies
the laying, moves his head clear of the telescope, and calls
“Ready” to indicate that the piece is ready to be fired.
(5) To refer the piece. The piece having been laid for
direction, to refer the piece, the command is: AIMING
POINT (SO-AND-SO), REFER. Without disturbing the
laying of the piece, the gunner brings the vertical hair of the
telescope on the new aiming point (referring point), keeping
the cross level bubble centered. He then reads and an-
nounces the deflection thus set. The piece may be laid sub-
sequently using this referring point as an aiming point. This
method affords a convenient means of laying when the initial
aiming point is either not convenient or not permanent. The
piece is normally referred to the aiming posts, but should also
be referred to one or more distant referring points for accuracy
and permanence. The chief of section records the deflection
and a description of each referring point in his notebook.
The gunner records the deflection and aiming point in current
use on a convenient part of the shield.
(6) To record base deflection. At the command record
BASE DEFLECTION, the gunncr records the deflection set on his
36
telescope upon some convenient part of the shield or upon a
data board (par. 44).
(7) To measure a deflection. The command is: AIMING
POINT ( SO-AND-SO), MEASURE DEFLECTION. The
piece having been established in direction, the gunner turns
the telescope until the vertical hair is on the aiming point.
He then reads and announces the deflection.
(8) To ma^e corrections for aiming post displacement.
See paragraph 36.
22 . NO. 1 . a. Enumeration of duties, (i) To set the
angle of site.
(2) To set the range.
(3) To set the elevation.
(4) To lay for elevation.
(5) To open and close the breech.
(6) To call “Set.”
(7) To fire the piece.
(8) To use the rammer.
b. Detailed description of duties, (i) To set angle
of site, (a) When an angle of site is to be used, the initial
series of fire commands for opening fire will contain the
command for site. The command is, for example: SITE 305.
For subsequent rounds, the site setting is increased (de-
creased) at the command up (down) (so much).
(b) No. I is first taught to read angles of site on the site
scale and then to set angles of site. To set an angle of site.
No. I turns the angle of site worm knob until the announced
site is shown. The angle of site is indicated by a scale grad-
uated in hundreds of mils from o to 6 and a micrometer scale
graduated in mils. A site of 300 is horizontal. No. i first
sets the index in the proper section of the scale in hundreds
of mils and then sets the units on the micrometer scale. The
last motion in setting the angle of site should be in the direc-
tion of increasing site.
(2) To set elevation. No. i is first taught to read eleva-
tions on the elevation scale and then to set elevations. To
set an elevation. No. i sets the angle of site at 300 (or at
an announced site) and sets the announced elevation on
the elevation scale. The elevation is indicated by a scale
37
graduated in hundreds of mils from minus too to plus 1200
and a micrometer scale graduated from zero to too mils.
No. I grasps the elevating knob and turns it until the an-
nounced elevation is shown, making sure that the last move-
ment is in the direction of increasing elevation.
(3) To lay for elevation. No. i turns the cross leveling
worm knob and centers the cross level bubble. Having per-
formed the duties described in (i), (2), and (3) above, he
turns the elevating handwheel and elevates or depresses the
tube until the longitudinal bubble is centered making sure
that his eye is directly opposite the bubble and that the last
movement is in the direction in which it is most difficult to
turn the handwheel.
(4) To open and close the breech, (a) To open breech.
No. I grasps the breech operating lever handle with his left
hand, pushes down on the handle to release the catch, and
draws it toward him and to the rear, opening the breech.
{b) To close the breech. No. i grasps the operating
handle with his left hand and pushes it forward and away
from him until the breech is closed and the latch is engaged.
(5) To call “Set." No. i calls “Set” when the piece has
been loaded, the breech closed, and the piece laid for site
and elevation.
(6) To fire the piece. At the command of the chief of
section, no. (so-and-so) fire. No. i grasps the handle of the
lanyard and fires the piece. If the chief of section commands
WITH THE LONG LANYARD, No. I attaches the long lanyard to
the short lanyard and fires as previously described. In case
of a misfire, the instructions contained in paragraph 42 will
be followed.
(7) To use the rammer. Normally the rammer (bore
brush) will be handled by No. i. The rammer and rammer
staff are used to extract unfired rounds or cartridge cases
which cannot be ejected by the extractor. To extract a car-
tridge case. No. i removes the rammer (bore brush) from
the rammer staff, inserts the rammer staff in the bore, and
lightly taps the bottom of the inside of the case until it is
loosened and can be pushed out of the chamber. No. 2,
standing at the breech, receives the cartridge case in both
38
hands. To extract an unfired round, the procedure described
in paragraph 41 will be followed.
23. NO. 2 . a. Enumeration of duties, (i) To load
the piece.
(2) In volley fire, to call out the number of the round.
(3) When necessary, to assist No. 6 in shifting the left
trail.
(4) To inspect the chamber and bore when the breech
is opened in order to insure that they are clear.
b. Detailed description of duties, (i) 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 front of the
rotating band. After resuming his position facing the gun-
ner, he inserts the round in the breech and pushes it home
with his right hand. He must use care, especially at higher
elevations, to avoid injuring his hand. When necessary to
insert his hand into the breech recess to push the round home,
he should first close his fist. No. 2 will be particularly care-
ful to avoid striking the fuze against any portion of the piece.
A round to be loaded will be held well out of the path of the
recoil until the piece is again in battery (AR 750-10).
(2) To call out number oj round. To insure that the cor-
rect 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 ex-
ample, when two rounds are to be fired at 2800, he calls out,
“2800 two, last round.” He should not speak more loudly
than is necessary to insure his being heard by the members
of his own howitzer squad.
(3) When necessary, to assist No. 6 in shifting left trail.
No. 2 assists No. 6 in shifting the left trail as directed by the
gunner. The command is; MUZZLE RIGHT (LEFT), and
the trail is shifted in the opposite direction so that the muzzle
is swung in the direction indicated. At the gunner’s com-
mand or signal to stop shifting, Nos. 2 and 6 lower the trail
to the ground.
(4) To inspect the chamber and bore when the breech is
open to insure that they are clear. No. 2 will inspect the
39
chamber and bore after each round is fired to make certain
the chamber is clear and the bore is free of any residue from
charge.
24 . NO. 3 . a. Enumeration of duties, (i) To make
the prescribed setting of impact fuzes.
(2) To set the fuze setter.
(3) To set time fuzes.
(4) When necessary, to assist No. 7 in shifting the right
trail.
b. Detailed description of duties, (i) To make pre-
scribed setting of impact fuzes, (a) The fire commands for
opening fire will contain a designation of the setting desired
when the prescribed fuze can be given more than one setting.
(b) If the command is fuze quick. No. 3 will verify the
setting and reset to quick fuzes which may be set delay.
(c) After firing is completed, No. 3 will reset to quick
any fuzes which have been set delay.
(2) To set fuze setter, (a) The initial series of fire com-
mands for opening fire with time-fuzed projectiles will con-
tain the data to be set on the fuze setter. These commands
are, for example: CORRECTOR 28, TIME 18.0. The cor-
rector may be changed by announcing a new corrector, for
example, “Corrector 33;” the time may be changed by an-
nouncing a new time, for example, “Time 22.4.”
(b) No. 3 sets off on the fuze setter the announced time,
and corrector if used. If a corrector is not used, the fuze
setter corrector setting should be 30.
(3) When the fuze setter is used in setting time fuzes,
No. 3 sets off the desired setting on the fuze setter and places
it over the fuze. He then presses down firmly on the fuze
setter and rotates it in a clockwise direction until the lugs
on the fuze setter engage with the slots on the fuze. He
continues to rotate the fuze setter in a clockwise direction
until it can be turned no further. This produces the same
setting on the fuze as was set on the fuze setter. When the
hand fuze setter wrench is used, care should be taken to
always set the fuze in the same direction. If the desired
time setting is passed, the time ring on the fuze should be
turned back several seconds and then continued in the origi-
40
nal direction until the desired time is again opposite the
index.
(4) When necessary, to assist No. 7 in shifting right trail.
No. 3 assists No. 7 in shifting the right trail as directed by
the gunner. The command is: MUZZLE RIGHT (LEFT),
and the trail is shifted in the opposite direction so that the
muzzle is swung in the direction indicated. At the gunner’s
command or signal to stop shifting, Nos. 3 and 7 lower the
trail to the ground.
25 . NO. 4 . a. Enumeration of duties, (i) To assist
No. 3 in setting time fuzes.
(2) To pass the round to No. 2.
b. Detailed description of duties, (i) To assist No.
5 in setting time fuzes. See paragraph 24b (3).
(2) To pass the round to No. 2. No. 4, with his left
hand under the cartridge case, his right hand under the
projectile, taking care that the projectile and cartridge case
do not separate, so passes the round to No. 2 that No. 2 is
able to grasp the base of the cartridge case in his right hand.
26 . NO. 5 . a. Enumeration of duties, (i) To set out
aiming posts.
(2) To prepare charges.
(3) To pass the round to No. 4.
(4) To replace increments in the cartridge case before
rounds are replaced in their containers.
b. Detailed description of duties, (i) To set out
aiming posts. When so directed by the chief of section. No.
5 sets out the aiming posts under the guidance of the gunner
(see par. 35).
(2) To prepare charges. The fire commands for open-
ing fire will include the designation of the charge. No. 5
verifies the number of increments and removes those incre-
ments numbered higher than the charge designated. He
then replaces the remaining increments in the cartridge
case in their original numerical order. After No. 5 has
prepared the charge. No. 6, assisted by No. 7, assembles the
projectile to the cartridge case. Care must be used to pre-
vent damage to the lip of the cartridge case.
41
(3) To pass the round to No. 4. No. 5 will pass the
round to No. 4 in the most convenient manner.
(4) To replace increments in cartridge case before rounds
are replaced in their containers. Under the personal super-
vision of the chief of section, No. 5, assisted by Nos. 6 and 7,
replaces increments in cartridge cases for all ammunition
prepared for firing but not fired. He carefully checks to
see that all seven increments are present, in the proper con-
dition, assembled in the proper numerical order, and that
they are of the proper lot number.
27 . NO. 6. a. Enumeration of duties, (i) To remove
ammunition from containers.
(2) To assist No. 5 in preparing charges.
(3) When necessary, assisted by No. 2, to shift the left
trail.
(4) To replace unused ammunition in containers.
b. Detailed description of duties, (i) To remove
ammunition from containers. Assisted by No. 7, No. 6 re-
moves rounds from their containers and arranges them so that
they are within easy reach of No. 5. He inspects each round
to see that it is free from sand and dirt and that the rotating
band is not burred. With an oily cloth, he wipes off any for-
eign matter. Projectiles with burred rotating bands should
be placed aside until he can remove the burs with a file.
(2) To assist No. 5 in preparing charges. When so di-
rected, Nos. 6 and 7 assist No. 5 in preparing charges as de-
scribed in paragraph 26b (2).
(3) When necessary, assisted by No. 2, to shift left trail.
When so directed by the gunner. No. 6, assisted by No. 2,
shifts the left trail (see par. 23b (3)).
(4) To replace unused ammunition in containers. Under
the personal supervision of the chief of section and assisted
by No. 7, No. 6 replaces unused ammunition in containers,
being careful that the lot number on the ammunition corre-
sponds to the lot number on the container. When sealing the
container, he includes, in a visible position under the seal, the
slip of paper (officer’s certificate) obtained from the chief of
section.
42
28 . NO. 7 . a. Enumeration of duties, (i) To assist
No. 6 in removing ammunition from containers.
(2) To assist No. 5 in preparing charges.
(3) To keep empty cartridge cases out of the way of the
cannoneers.
(4) When necessary, assisted by No. 3, to shift the right
trail.
(5) To assist No. 6 in replacing ammunition in containers.
b. Detailed description of duties, (i) To assist No. 6
in removing ammunition from containers. No. 7 assists No.
6 in removing rounds from their containers as described in
paragraph 27b (i).
(2) To assist No. 5 in preparing charges. Nos. 7 and 6
assist No. 5 in preparing charges as described in paragraph
26b (2).
(3) To \eep empty cartridge cases out of way of cannon-
eers. No. 7 piles the empty cartridge cases in rear of the
right trail where they will be out of the way of the cannoneers.
(4) When necessary, assisted by No. 3, to shift right trail.
When so directed by the gunner, No. 7, assisted by No. 3,
shifts the right trail (see par. 24b (4)).
(5) To assist No. 6 in replacing ammunition in containers.
No. 7 assists No. 6 in replacing rounds in containers in a man-
ner similar to that described in paragraph 27b (4).
Section II. DIRECT LAYING
29. GENERAL. Delivery of fire by direct laying demands
a high degree of training in its special technique, since it
requires the section to operate as an independent unit. This
training is based on the technique employed in the normal
mission of indirect laying. The high standards of speed
and accuracy required in direct laying are even more impor-
tant when the target may be returning the fire. There are
two basic systems of sight control: the two-man, two-sight
system (par. 31); and the one-man, one-sight system (par.
32). When ordered by the executive to conduct the fire of
his piece, the chief of section will designate the system to be
used. Training should include both systems. For infor-
mation on training, see FM 6-140.
43
30. PREPARATORY STEPS, a. Prepare range card.
At the earliest possible time, a range card should be pre-
pared indicating the ranges and corresponding elevations to
critical points in likely avenues of enemy tank or vehicle
approach. Where no prominent terrain features are avail-
able, stakes may be driven in the ground for range reference
points. Corresponding elevations for charge 6 and the
angle of site to key points in the sector may be noted on the
range card (for use with the one-man, one-sight system).
In preparing the range card, the range line in the reticle
which will be used for different charges and different pro-
jectiles in firing at various targets should be included in
addition to the ground range. As time permits, the range
card will be improved by noting thereon ranges obtained by
firing, pacing, taping, from vehicular odometer readings,
and from measurements made from a map or survey. (See
fig. i8.)
b. Clear area. The sector of fire for the piece must be
cleared of all obstructions which will endanger battery per-
sonnel when the piece is fired.
44
31. TWO-MAN, TWO-SIGHT SYSTEM, a. Chief of
section, (i) Enumeration of duties. («) To prepare a
range card.
{b) To conduct the fire of his piece on order of executive,
(c) To provide for the clearance of all immediate obstruc-
tions within his sector which will endanger battery personnel
when the piece is fired.
{d) To select or identify the target.
(e) To determine the lead and range.
(/) To announce initial commands.
(g) To announce subsequent commands, based on the
observed effect.
(2) Detailed description of certain duties, (a) To pre-
pare a range card. See paragraph 30a.
(^) To identify the target. The battery executive will
give the preliminary command: target (so-and-so), fire at
WILL. The chief of section upon receiving this command,
must correctly identify the target to his section.
(c) To determine initial lead. The chief of section ob-
serves the target, estimates its lateral speed, and (based on the
speed) estimates the lead in mils. The appropriate leads in
mils for targets moving at typical tank speeds when shell
HE- AT or shell HE with charge 6 is fired are as follows:
Lateral speed Lead
Slow (0 to 5 m. p. h.) 5 mils
Medium (5 to 10 m. p. h.) 10 mils
Fast ( 10 to 15 m. p. h.) 15 mils
{d) To determine initial range. The chief of section esti-
mates the initial range to the target and determines the appro-
propriate range line on the reticle of the elbow, telescope. The
reticle pattern for shell HE-AT M67 is also used for charge 6.
For other charge or reticle pattern the aiming data chart issued
with the elbow telescope is used to determine the appropriate
range line. A range card with accurately determined ranges
to key points provides the best means for estimating the initial
range.
(e) To announce initial commands. The chief of section
will announce fire commands containing the following ele-
ments in sequence:
669119° — 45-
■4
45
1. Designation of target. The command is; TAR-
GET (SO-AND-SO).
2. Projectile, charge, and fuze. The commands spec-
ify the appropriate items in sequence, such as
SHELL HE, CHARGE 6, FUZE DELAY; OR SHELL ANTI-
TANK. Shell HE-AT will be used against tanks
except where bracketing methods of adjustment
are employed. When shell HE-AT is not avail-
able or when bracketing methods are employed,
shell HE is used. With shell HE-AT, no com-
mand for charge or fuze is necessary. When fir-
ing shell HE against close-in targets, use charge
6 since the trajectory with this charge approx-
imates that for HE-AT. Against distance targets
or stationary targets where bracketing methods
are used, charge 7 may be fired. Fuze delay
should be used against tanks, armored vehicles,
fortifications, or personnel. If less than 50 per-
cent of the rounds fired against personnel during
adjustment are ricochet bursts, the fuze setting
should be changed to superquick. Concrete
piercing fuze with HE shell should be used,
whenever available, against concrete pillboxes or
fortifications.
3. Lead. The command is: LEAD (SO MUCH).
4. Method of fire. Usually the command is; CON-
TINUOUS FIRE, the piece being loaded and laid
as rapidly as possible and fired at the command of
the gunner.
5. Range. The command is: RANGE (SO MUCH).
Note. Commands in 2 and 4 above may be omitted when the state
o£ training of the howitzer squad or standing operating procedure permit.
(/) To determine subsequent data. See paragraph 33.
fg) To announce a change in lead and range. During ad-
justment, changes in lead to be applied to the lead being used
are commanded as right (left) (so much). Range is in-
creased by the command add (so much) and decreased by the
command drop (so much).
b. Gunner, (i) Enumeration of duties, (a) To center
the cross level bubble on the panoramic telescope mount.
46
(^) To set the elevation index and micrometer of the
panoramic telescope at zero.
(c) To set the azimuth scale and micrometer of the pano-
ramic telescope at zero.
(d) To track the target.
(e) To command fire.
(/) To re-lay on the target immediately after the piece has
fired.
(g) To repeat his actions in accordance with the fire com-
mands and subsequent changes thereto.
(2) Detailed description of certain duties, (a) To lay on
the target with announced lead and trac\ the target. The
gunner sets his azimuth scales at zero and tracks the target
with the traversing handwheel, using the center of the
visible mass as an aiming point and keeping the vertical
hair of the telescope ahead of the target by measuring the
announced lead on the reticle scale (fig. 19). When time
does not permit the chief of section to announce the lead, it
is determined by the gunner.
(b) To give command to fire. He gives the command
FIRE, when ready, after No. i has called “Set.”
C. No. 1 . (i) 'Enumeration of duties, (a) To lay for
range, using the elbow telescope.
(h) To track the target.
(c) To call “Set” when the piece is loaded and the cor-
rect range line is on the center of the visible mass of the
target.
(d) To re-lay on the target immediately after the piece
has fired.
(e) To repeat his actions in accordance with the fire com-
mands and subsequent changes thereto.
(2) Detailed description of certain duties. To lay for
range, using elbow telescope. In direct laying, when so
directed. No. i lays for range (with the correct angle of site
automatically applied) by using the appropriate range line
in the reticle of the elbow telescope. No. i, using the elevat-
ing handwheel, keeps the range line corresponding to the
announced range on the center of the visible mass of the
target (fig. 20).
47
d. No. 5 . (i) Enumeration of duties. («) To open
and close the breech.
{b) To indicate that the piece is loaded by tapping No. i
on the shoulder.
(c) To fire the piece at the gunner’s command.
Figure ig. Gunner’s sight picture, two-man, two-sight system
{lead 75 mils).
(2) Detailed description of certain duties. To open and
close breech and fire piece. No. 5 will take position in rear
of No. I and will open and close the breech and fire the
piece (par. 22).
e. Remainder of squad. All duties are the same and
are performed in the same manner as in indirect laying.
48
32. ONE-MAN, ONE-SIGHT SYSTEM, a. Chief of
section. The duties of the chief of section afe the same as
in the two-man, two-sight system (par. 31 a).
b. Gunner, (i) Enumeration of duties, (af To lay
on the target with the announced lead and range measured
on the scales of the panoramic telescope reticle.
(b) To command fire when the piece is laid.
(c) To re-lay on the target immediately after the piece
has been fired.
(d) To repeat his actions in accordance with the fire com-
mands and subsequent changes thereto.
49
(2) Detailed description of certain duties, (a) To lay
for both direction and range. The gunner matches the in-
dexes on the telescope mount and sets the elevation indexes
and azimuth scales of the panoramic telescope at zero. After
laying approximately on the target, he centers the telescope
mount cross level bubble. He then lays on the target with
Figure 21. Gunner’s sight picture, one-man, one-sight system
{lead 15 mils; range 600 yards).
the announced lead and range measured on the scales of
the reticle (fig. 21).
{b) Other duties. Performed as in the two-man, two-
sight system (par. 31b).
c. No. 1 . (i) Enumeration of duties, (c) To level
longitudinal and cross level bubbles initially.
{b) To open and close the breech.
50
(c) To call “Set” when the piece is loaded.
(d) To fire the piece at the gunner’s command fire.
(2) Detailed description of certain duties. No. i opens
and closes the breech and fires the piece as described in
paragraph 2a.
d. Remainder of squad. All duties are the same and
are performed in the same manner as in indirect laying.
33. CONDUCT OF FIRE. a. Trajectory character-
istics. When HE shell with charge 6 or shell HE-AT is
fired, the following trajectory characteristics will govern the
manner of conducting fire:
(1) Ranges from o to .foo yards. Within these range
limits, the trajectory will be too flat to permit an 8-foot tank
to pass under it. The upper range of 400 yards is the ideal
at which to open fire on an approaching tank, since rapid
fire can then be conducted without misses if deflection is
correct.
(2) Ranges from 400 to 700 yards. These range limits
include the zone in which the trajectory is sufficiently flat
to permit direct estimation of errors without actual bracket-
ing of the target. Assuming zero vertical dispersion, if a
hit is obtained at the bottom of an 8-foot tank at the upper
limit (700 yards), a loo-yard range change (to 800 yards)
will result in a round which will just brush the top of the
tank. During adjustment within this zone, range changes
should seldom be more than 100 yards, and frequently range
changes of 50 yards will be sufficient. The upper limit is
the greatest range at which fire should be opened unless tac-
tical conditions require otherwise. The second shot (or
certainly the third) should be a hit.
(3) Ranges from 700 to i,joo yards. The range limits
fromi 700 to 1,300 yards include a zone in which hits are
reasonably possible. Ordinarily, bracket methods are used
to obtain an adjustment for range in this zone. Fire should
npt be opened at these ranges unless surprise is of no con-
sideration. Dispersion is a considerable factor in firing at
targets within this zone.
(4) Ranges over 1,^00 yards. At ranges above 1,300
yards, direct laying is not advisable against moving targets.
51
However, it would be pointless to withhold fire until the
target came within a range of 1,300 yards if the gun posi-
tion had been disclosed. Dispersion is the controlling factor.
Ranges must be known accurately or determined by
bracketing.
b. Vertical displacement. The vertical displacement
for each loo-yard range change, with the 105-mm howitzer
M2 or M2A1, firing charge 6, is shown in the following table:
Range
Vertical dis-
placement
Range
Vertical dis-
placement
Yards
Feet
Yards
Feet
100
1
800
8.5
200
2
900
9.5
300
3
1,000
11.5
400*
4
1,100
12.5
500
5
1,200
13.5
600
6
1,300*
15
700*
7
•Critical direct-laying ranges.
CHAPTER 8
ADDITIONAL INFORMATION ON
SERVICE OF THE PIECE
34 . ACCURACY IN LAYING. Sighting and laying in-
struments, fuze setters, and elevating and traversing mecha-
nisms will be so manipulated as to minimize the effects of lost
motion. This_requires that all bubbles be accurately centered
and that last motions in setting instruments and in laying
always be in the directions prescribed. The gunner and any
other cannoneers who have duties in connection with laying
the piece will invariably verify the laying after the breech
has been closed.
35 . AIMING POSTS, a. When a suitable natural aiming
point is not visible, the piece, after it has been laid initially
for direction, is referred to the aiming posts as described in
paragraph 2ib (5). Two aiming posts are used for each
piece. Each post is equipped with a light for use in firing
at night. One post is set up in a convenient location at least
100 yards from the piece. The other post is set up at the mid-
point between the first post and the piece, and is lined in by
the gunner so that the vertical hair of his telescope and the
two aiming posts are all in line. Distances should be deter-
mined by pacing or other method to insure that the far post
is set at twice the distance to the near post. Any lateral dis-
placement of the piece during firing can then be detected
easily and corrected as indicated in paragraph 36. For night
use, the lights should be adjusted so that the far one will
appear several feet higher than the near one; thus the two
lights will clearly establish a vertical line on which the vertical
hair of the telescope can be laid.
b. The panoramic telescope is mounted a considerable dis-
tance away from the center of rotation of the top carriage.
As a result, large changes in deflection will cause misalignment
of the aiming posts because of movement of the sight on an
arc around the center of the top carriage. Placing the aim-
53
ing posts between 600 and 700 mils to the left front (deflection
2600 to 2500 when the howitzer is in center of traverse) will
minimize the effects of this condition.
36 . CORRECTION FOR DISPLACEMENT. When
the gunner notes that the vertical hair of the telescope is dis-
placed from the line formed by the two aiming posts (or
aiming post lights), he lays in such a manner that the far
aiming post (light) appears exactly midway between the
near aiming post (light) and the vertical hair (fig. 22). If
the displacement is due to traverse of the piece, the gunner
continues to lay as described above. However, if the dis-
FAR POST PAR POST
Figure 22. Displacement of aiming posts.
placement is due to progressive shift in position of the car-
riage from shock of firing or other cause, the gunner will
notify the chief of section, who, at the first lull in firing,
will notify the executive and request permission to realign
aiming posts. To perform the alignment, the piece is laid
with the sight picture described above. The far aiming post
is moved into alignment with the vertical hair of the tele-
scope, and then the near aiming post is aligned. If, due to
terrain conditions, it is impracticable to move one of the
54
two aiming posts, the piece is laid for direction and referred
to the aiming post which cannot be moved. The other post
is aligned and new deflection setting reported to the executive.
37. REPORTING ERRORS. All members of the how-
itzer squad are trained to report to the chief of section errors
in setting or laying discovered after the command fire has
been given. The chief of section will immediately report
errors to the executive, as prescribed in paragraph 20 b (8).
38. CEASE FIRING. The command cease firing nor-
mally is given to the howitzer squad by the chief of section,
but in emergencies anyone present may give the command.
At this command, regardless of its source, firing will cease
immediately. If the piece is loaded, the chief of section will
report that fact to the executive. Firing is resumed at the
executive’s announcement of the range or elevation.
39 . 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 execu-
tive. Firing will be resumed at the executive’s command
RESUME FIRING.
40. CHANGE IN DATA DURING FIRING. The an-
nouncement to the howitzer squad of any new element of
firing data is a command to stop all firing previously or-
dered but not yet executed. If the piece is not loaded when
a new element of firing data is announced, the new data
will be set off and firing resumed at the announcement of the
elevation. If the piece is loaded and the new data require
a change in the fuze setting, the chief of section will suspend
firing and report to the executive that the piece is loaded.
The piece will be unloaded (par. 41 ) or firing will be resumed
only on orders of the executive. (If no change in the fuze
setting is required, the new data are set off and the firing is
resumed.)
55
41 . TO UNLOAD PIECE, a. When the command un-
load is given, No. i opens the breech slowly. No. 2, stand-
ing at the breech, receives the ejected round or cartridge
case.
b. Should the extractor fail to eject the complete round,
the assembled staff and rammer (or staff and unloading de-
vice, if available) is used. An officer sees that the recess in
the head of the rammer or device is free from obstructions.
Under the direct supervision of an officer, No. i inserts the
rammer or device in the bore until the head incloses the fuze
and comes in contact with the projectile. He pushes and, if
necessary, taps the rammer staff lightly until the round is dis-
lodged from its seat. He then pushes it oUt of the breech;
No. 2 receives it.
c. If the extractor has ejected the cartridge case but not
the projectile. No. i fills the chamber with waste and closes
the breechblock. He dislodges the projectile as prescribed in
b above. No. 2 then opens the breech, removes the waste,
and receives the projectile as No. i pushes it to the rear.
d. When practicable, the procedure prescribed in TM
9-1900 should be followed.
42 . MISFIRES. In the event of a misfire, at least two
attempts to fire the primer will be made before the executive
will command unload. The procedure is the same as in
paragraph 41. If the extractor ejects the round, the round
will be disposed of as prescribed in TM 9-1900. If the ex-
tractor ejects only the cartridge case (as frequently happens),
the case will be immediately thrown clear pf all personnel
to prevent injury in case of a hangfire. Another cartridge
case with the proper charge will be inserted in the breech,
care being taken not to damage the case. Authority to fire
the round will be obtained from the officer conducting fire.
43 . AMMUNITION. Ammunition must be protected
from damage, especially the rotating bands and cartridge
cases. It is sorted and stored by lots. It is kept in containers
as long as practicable. Whether in or out of containers, it
is protected from dirt and ground moisture by being placed
56
on paulins or raised o£E the ground. It is protected from sun
and rain by a paulin or other shelter placed above it. The
powder temperature is kept uniform for any one lot; to per-
mit free circulation of air, wood or brush is placed between
layers of unboxed rounds. If time permits, trenches for am-
munition will be dug to minimize the effects of a direct hit.
The ammunition is stacked, with each stack containing not
more than 75 rounds and being not more than four layers
high. Stacks are at least 10 yards apart.
44. SECTION DATA BOARD. When positions are
occupied for more than a few hours, each chief of section
should maintain a section data board on which he records
such items as base deflection, calibration corrections and stand-
ing corrections when appropriate, minimum range or eleva-
tion, data for primary defensive fire missions, and other data
the need for which may be urgent.
57
CHAPTER 9
CARE AND ADJUSTMENT OF SIGHTING
AND FIRE-CONTROL EQUIPMENT
45 . GENERAL. Special care is required .to insure the
positive and accurate functioning of the sighting and fire-
control mechanisms. Denting of the soft metal surfaces and
scratching of the lenses must be prevented. The steel locat-
ing surfaces should be kept covered with a light film of
lubricant to prevent corrosion. Dirt should be removed
from optical surfaces by brushing lightly with a camel’s-hair
brush. Oil or grease should be removed from the glass by
applying liquid lens soap or, if cleaning materials are not
available, by breathing on the glass and then wiping lightly
with lens paper. Battery personnel are forbidden to disas-
semble any part of the gunner’s quadrant, panoramic or elbow
telescopes, telescope mounts, or range quadrant, but are per-
mitted to perform certain adjustments. The procedures de-
scribed in paragraph 47 may be used to insure accuracy of
the sighting and laying mechanisms. In general, the sight-
ing and laying equipment is in adjustment when, with the
tube and trunnions level, the lines (or planes) of sighting
(vertical and horizontal) are parallel to the axis of the bore,
all indexes and scales are zeroed (the site scale is zeroed at
3 (300), all other scales at zero), and the bubbles are centered
or within the allowable error.
46 . EQUIPMENT FOR TESTING. Equipment used
in testing the sighting and laying equipment consists of bore
sights, gunner’s quadrant, a plate with parallel surfaces, and
a testing target and plumb line. For adjustment, a 3-inch
screw driver, a 5-inch heavy duty screw driver, an adjustable
wrench, and a 9- to 16-inch socket wrench with handle are
the only tools required. The target for boresighting may be
a terrain object at least 1,000 yards away or a testing target be-
tween 50 and 100 yards in front of the tube. Caution:
Care should be taken that the correct testing target is used.
58
since targets for use with different panoramic telescopes and
extensions are not interchangeable. See TM 9-325 for in-
formation concerning proper displacement for the type sight
and extension being tested.
47 . TESTS AND ADJUSTMENTS. Tests and adjust-
ments are performed before firing and during lulls in firing.
Competent battery personnel may make the following tests
and adjustments:
a. Gunner’s quadrant, (i) End-for-end test. ■ {d)
Place the weapon in the center of traverse and level the
trunnions to within i mil as in b (i) below.
{h) Set both the index arm and the micrometer scales
at zero and match the auxiliary index marks (use black
figures on micrometer).
(c) Place the quadrant on the leveling plates on the
breech ring, using the arrow on the frame to indicate the
direction of fire, and center the bubble of the quadrant by
elevating or depressing the tube with the elevating hand-
wheel.
( 4 ) Reverse the quadrant on the leveling plates. (Turn
it end for end.) The bubble should recenter itself. If it
does not, center the bubble if possible by turning the microm-
eter. Take the reading on the micrometer, divide the read-
ing by 2, and set the result on the micrometer. The result
is the amount of the plus correction to be applied to the
announced elevation. Example: The reading on the microm-
eter is 0.4 mil. The reading to be set on the micrometer is
0.4 “^2 = 0.2 mil.
If the bubble cannot be centered by use of the micrometer,
it will be necessary to set a minus reading of one graduation
(or — 10 mils) on the graduated arc. The bubble can now
be centered by turning the micrometer. Add the reading
on the arc to the reading on the micrometer.
Example: Reading on arc= — 10 mils; reading on microm-
eter =9.6 mils. Disregard signs and add:
10-1-9.6= 19.6 mils.
i9.6-i-2 = 9.S mils, reading to he set on the micrometer.
With this applied, place the quadrant back on the leveling
59
plates and center the bubble with the elevating handwheel.
Turn the quadrant end for end; if the bubble recenters itself,
the minus correction of — 01.2 mil to be applied to the an-
nounced elevation has been determined. If the bubble fails to
recenter itself, an error is indicated and the test must be
repeated.
If the necessary correction exceeds 0.4 mil, the quadrant
should be adjusted by ordnance personnel.
(2) Micrometer test. Set a reading of 10 mils on the
graduated arc, set the micrometer at zero (using black fig-
ures), and center the bubble by elevating the tube. Turn
the micrometer clockwise to a reading of 10 mils and set a
reading of zero on the graduated arc. If the bubble does not
center, there is an error in the micrometer and the quadrant
should be adjusted by ordnance personnel.
b. Adjustment of on-carriage equipment. The on-
carriage sighting and laying equipment is tested, and ad-
justed if necessary, prior to firing, to insure accurate laying
of the piece for deflection and for elevation. The following
steps should be taken to insure the desired accuracy:
(1) Carriage. In boresighting and testing, the trunnions
should be leveled and the tube placed in the center of traverse.
The trunnions should be leveled by leveling the ground un-
der the trails or by blocking the lower trail to the height of
the higher trail. The leveling of the trunnions should be
checked with a tested gunner’s quadrant (in conjunction
with a machined steel plate or piece of plate glass) placed
crosswise on the breech ring.
(2) Telescope mount. With the tube and trunnions level,
place a steel or glass plate having parallel sides on top of
the telescope mount. Level the telescope mount both cross-
wise and longitudinally by turning the cross leveling and
elevation knohs, using the tested gunner’s quadrant as a
level. If the elevation indexes on the rocker and the actuat-
ing arm and those on the elevation knob and the shaft do not
match, adjust them by moving the adjustable index on the
rocker or by adjusting the elevation knob index as needed.
If the cross and longitudinal level bubbles are not centered
within one graduation, adjustment may be made by ordnance
personnel.
60
(3) Range quadrant, (a) Elevation scales. Set the eleva-
tion scale to read zero. If the elevation micrometer does
not read zero, loosen the screws in the knob and move the
scale until the zero reading is opposite the index. Tighten
the screws and recheck. The elevation scale index plate may
be adjusted if necessary.
{b) Angle of site scales. Center the cross level and angle
of site bubbles by using the cross leveling worm knob and
the angle of site micrometer knob. If the angle of site scale
does not read 3 (300), loosen the screws and move the scale
until the figure 3 is in coincidence with the index. If the
angle of site micrometer does not read zero, loosen the screw
in the micrometer knob and move the scale until a zero
reading is indicated. Recheck to make sure that the cross
level and angle of site bubbles are centered and that the
angle of site scales read 3 (300).
(4) Boresighting. Place the issue bore sights in their
proper positions (or use improvised cross hairs on the muzzle
and sight through the firing pin hole, making certain that
the firing pin hole is actually centered when the breech is
closed). Sight the tube on the testing target or a sharply
defined distant aiming point. When using the testing Urget,
move it into alignment with the bore sights, normal to the
axis of the bore. When the tube is level, the testing target
may be positioned normal to the axis of the bore by placing
one of the vertical lines of the testing target diagrams parallel
to a plumb line.
(5) Panoramic telescope. («) Deflection adjustment.
Place the panoramic telescope in the mount and check to
see that the cross level and longitudinal level bubbles are
centered. Set the azimuth micrometer index opposite the
zero of the deflection scale. With the azimuth worm knob,
place the vertical cross hair of the telescope reticle on the
proper portion of the testing target or aiming point.
r. If the azimuth scale and the micrometer scale do
not indicate zero deflection and the error is less
than 50 mils, adjust in the following manner:
turn the azimuth worm knob until the zero of
the azimuth scale is opposite the index. Loosen
the three screws in the azimuth micrometer knob
669119 ” — 45 -
•5
61
and, while holding the azimuth worm knob,
slip the micrometer scale until the zero is oppo-
site the micrometer index. Tighten the screws
and recheck the scales for zero readings. Then
loosen the tangent locking screws at the front of
the telescope socket and adjust the tangent screws
until the vertical cross hair is on the. proper por-
tion of the testing target or aiming point.
Tighten the tangent locking screws and recheck.
2. If the error is greater than 50 mils, turn the azimuth
worm knob until the vertical cross hair is on the
proper portion of the testing target or aiming
point. Then adjust the micrometer scale to read
zero as above. If the azimuth scale does not
now read zero, loosen the four screws on the
collar above the scale and slip the scale around
until the zero is opposite the index. Tighten the
screws and recheck.
{b) Elevation adjustment. With the elevation knob, place
the zero horizontal cross hair of the telescope reticle on the
proper portion of the testing target or aiming point. If the
elevation micrometer does not indicate zero, loosen the
screws in the end of the knob, and, holding the knob, slip
the elevation micrometer until the zero graduation lines up
with its index; then tighten the screws and recheck the set-
ting. If the coarse elevation index does not indicate zero,
the adjustment should be made by ordnance personnel.
(c) Prism alignment. After adjusting the panoramic
telescope on the testing target or distant aiming point, note
carefully the position of the vertical and horizontal cross
hairs on the target. Turn the rotating head through 6,400
mils, taking care not to go past 6,400. The vertical and
horizontal cross hairs should be returned to exactly the same
position on the target. Turn the rotating head 6,400 mils
in the opposite direction, taking care not to go past 6,400.
The cross hairs should coincide with the first noted position.
If the cross hairs do not coincide after the rotating head has
been turned 6,400 mils in either direction, the telescope
should be returned to ordnance for adjustment.
62
(6) Elbow telescope. By observation, level ihe reticle with
respect to the testing target or distant aiming point by means
of the bracket rotating knob. If the N, or zero, range line
does not match the line on the testing target or distant aim-
ing point, loosen the worm clamping bolt and, with a screw
driver, bring the N range line in coincidence with the proper
line of the testing target or on the distant aiming point.
Tighten the worm clamping bolt. Recheck alignment. No
adjustment for deflection is provided.
63
CHAPTER 10
SECTION MAINTENANCE DRILL
48 . GENERAL, a. Inspection and maintenance are essen-
tial to insure that the howitzer section is ready to move and
to shoot at all times. Section drill on inspection and main-
tenance will make the work routine, thorough, and fast.
This drill is applicable when the prime mover and the
howitzer are close together.
b. The outline of duties in the section maintenance drill
assigns duties to all members of the section. When the sec-
tion is reduced in strength, the chief of section will assign
duties to insure that all maintenance steps are completed.
c. The inspections and maintenance operations performed
by the howitzer section are outlined in following paragraphs.
Details of all preventive maintenance services are contained
in the Technical Manuals of the particular equipment, and
in appropriate War Department Lubrication Orders.
d. It is routine that all materiel and equipment be kept
free from mud and dust at all times.
64
<D
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to -W 00 -ft
65
and security. latch.
'. Verifies presence of emer- 6. Reports, “No. 1 ready,
gency supply of gaso-
line, oil, water, and
rations.
49. DUTIES IN INSPECTION BEFORE OPERATION— Continued
a. Howitzer — Continued
C h z
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66
cannot remedy with-
out delay or assistance.
1. Inspects howitzer overall cover for 1. Assisted by No. 5, removes and re- 1. Assists No. 4 in removing and replac-
torn or worn places and for broken places muzzle end of howitzer over- ing muzzle end of howitzer overall
or missing fastenings. all cover. cover.
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67
49. DUTIES IN INSPECTION BEFORE OPERATION— Continued
b. Prime mover. (1) Truck.
Chief of Section Driver No. 6 No. 7
1. Commands section. Su- 1. Examines vehicle for 1. Examines vehicle for 1. Examines vehicle for
g s i §
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68
Checks for abnormal lights, and reflectors 7, Checks body, load, and
noises. on howitzer and prime tarpaulin for condition
i. Checks operation of mover. (Driver oper- and attachment.
choke while starting. ates switches.) 8. Reports, “No. 7 ready.”
Resets as required 7. Checks tools and equip-
during the warm-up. ment for presence,
Checks dash instru- condition, and mount-
ments and gauges for ing.
correct readings. 8. Reports, “No. 6 ready."
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69
during idle, accelera-
tion, and deceleration.
13. Reports, “D river
ready.”
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50 . DUTIES IN INSPECTION DURING MARCH,
a. Truck-drawn units.
S KJ
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® 5 5 .
I CC >0 to r» CO
72
\ Checks readinp: and action of all instruments and gauges,
k Listens for noises indicating malfunction of vehicle.
Chiej of section Gunnet Nos. 1 to 5
.. Supervises march discipline. 1. Observes prime mover for security. 1. Listen for noises indicating malfunc-
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73
51. DUTIES IN INSPECTION DURING HALT,
a. Howitzer.
Chief of Section Gunner No. 1 No. 2
1. Supervises inspection and 1. Checks condition and 1. Inspects breech end of 1. Checks tiros for bruises,
§ « 2 - «.
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74
5. Checks to see that drawbar is in 2. Inspects cradle lock strut for proper 2. Checks condition and security of
proper position and securely locked. fastening. black-out light.
!. Keports, “No. 3 ready.” 3. Checks bottom shield flap for security 3. Reports, “No. 5 ready.”
in traveling position.
4. Reports, “No. 4 ready.”
Chuf of Section Dfiver No. 6 No. 7
Supervises inspection and 1. Checks and replenishes 1. Checks transfer, trans- 1. Checks brake drums and
maintenance at halt. supply of fuel, oil, and mission, axles, and cen- wheel hubs for over-
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75
I. Checks body and tar-
paulin for condition.
Checks load for shifting.
I. Reports, “No. 7 ready.”
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76
52. DUTIES IN INSPECTION DURING FIRING,
a. Howitzer.
W l- 05
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77
53. DUTIES IN INSPECTION AND MAINTENANCE AFTER OPERATION,
a. Howitzer.
o''g ° “
1
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78
gency rations, oiJ
ter, and gasoline.
Receivers reports from
members of the section
as they complete in-
spection.
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'. Checks all accessories for 6. Checks condition and 8. Assists No. 6 in cleaning
mounting and condi- security of propeller vehicle,
tion. Checks all belts shafts, center bearings, 9. Assists driver in lubri-
for condition and ad- and vents. Removes eating vehicle,
justment. any foreign ’material.
6
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81
sisted by Nos. 6 and 7,
cleans, inspects, and
rewinds cable if winch
has been used during
53. DUTIES IN INSPECTION AND MAINTENANCE AFTER OPERATION-
Continued.
b. Prime mover (2) Tractor.
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54. DUTIES IN WEEKLY INSPECTION AND MAINTENANCE,
a. Howitzer.
Chiej of section Gunner; Nos. 1 to 5
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i. Cleans and inspects glass 4. Checks all lights, light 6. Checks all parts of steer-
and rearview mirrors. switches, and reflec- ing linkage for secur*
Adjusts mirrors. tors for condition and ity, condition and ad-
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water and dirt from tools,
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54. DUTIES IN WEEKLY INSPECTION AND MAINTENANCE— Continued
b. Prime mover, (l) Truck — Continued
Driver No. 6 No. 7
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(2) Tractor.
Chief of Section Driver No. 6 No. 7
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pervises detailed inspec- water, and replenishes nozzle; checks seal and condition and mount-
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89
CHAPTER 11
DECONTAMINATION AND DESTRUC-
TION OF EQUIPMENT
Section I. DECONTAMINATION
55. GENERAL, a. Whenever chemical attacks are antici-
pated, cover all unpainted surfaces with oil. Keep propell-
ing charges, fuzes, and primers in sealed containers, and
cover projectiles with a paulin.
b. After a gas attack, remove the oil with dry-cleaning
solvent, using rags attached to sticks. Decontaminate painted
surfaces with a mixture of equal parts by weight of decon-
taminating agent (chloride of lime) and water. If chloride
of lime is not available, use large quantities of hot water.
56. AFTER EXPOSURE TO VESICANT GAS. Un-
painted surfaces exposed to vesicant gas (mustard or lewisite)
must be treated with a mixture of i part agent, decontaminat-
ing, noncorrosive, and 15 parts solvent (acetylene tetra-
chloride) by weight. If these materials are not available,
wash the unpainted surfaces with warm water and soap
several times. Clean ammunition the same way. Caution:
Do not use dry chloride of lime near ammunition. Flam-
ing occurs when it touches liquid vesicants.
57. AFTER EXPOSURE TO NONVESICANT GAS.
Unpainted surfaces exposed to nonvesicant gas may be cleaned
with solvent or denatured alcohol, wiped dry, and then
coated with oil. (See TM 3-220 for further information on
decontamination.)
Section II. DESTRUCTION
58. GENERAL, a. When capture by the enemy is immi-
nent, materiel will be destroyed. Such destruction is a com-
mand decision to be carried out only on authority delegated
by the division or higher commander. All howitzer batteries
will prepare plans for destroying their materiel. Plans must
be flexible in the time, equipment, and personnel required.
90
b. Training will not involve actual destruction of materiel,
but will stress that —
(1) Materiel will be destroyed only when such action is
necessary in the judgment of the military commander con-
cerned. (See a above.)
(2) The sequence laid down for the method selected will
be strictly followed, to insure uniform destruction.
(3) The same essential parts will be destroyed on all
weapons or vehicles to prevent the enemy from reconstructing
a complete weapon or vehicle from several damaged ones.
C. Some methods require special tools and equipment not
normally items of issue. Special issue of such items is a
command decision. If magneto exploders are not available,
the generator of a standard field telephone can furnish cur-
rent for tetryl electric blasting caps. With nonelectric blast-
ing caps, at least 5 feet of Bickford safety fuze must be used
to allow personnel firing to reach cover. See FM 5-25 on
demolition charges.
d. Methods are given in the order of their effectiveness.
Use method No. i where possible, other methods in the
priority shown. ,
59. OPTICAL AND FIRE CONTROL EQUIPMENT.
Remove all detachable equipment before destroying the rest
of the weapon. If evacuation is possible, carry detachable
items and thoroughly smash nondetachable items. If evacua-
tion is not possible, thoroughly smash all optical equipment
and burn slide rules, firing tables, charts, etc.
60 . TUBE, BREECH, RECOIL MECHANISM, AND
CARRIAGE. When simultaneous destruction of all these
items is impossible, destruction of the tube, breech, and re-
coil mechanism has priority.
a. Method No. 1 . (r) Start draining oil by inserting
oil release in filling hole in recuperator cylinder front head.
(2) Place armed (safety pin removed) antitank grenade,
or armed (safety pin removed) antitank rocket in tube about
21 inches forward of forcing cone, ogive end toward breech.
(3) Load piece with HE round, unfuzed if possible. Do
not use HE antitank shell.
91
(4) Fire piece from fox hole at least too feet to rear, about
20° off line of fire. Elapsed time: 2 to 3 minutes. Danger
zone: 500 yards.
b. Method No. 2 . (i) Insert four */2 -pound blocks of
TNT in tube near muzzle, nine in chamber. Close breech-
block as far as possible without damaging safety fuze.
(2) Plug muzzle tightly with earth for 12 inches. If
plugging is not possible, insert more TNT blocks.
(3) Place two unfuzed HE shells, with booster left in
place, upright on top of carriage just below cradle between
elevating arcs. Cover each fuze opening with '/2 pound of
TNT. Ten 54 -pound blocks of TNT may be substituted for
HE shells.
(4) Detonate all charges simultaneously, using detonat-
ing cord, tetryl nonelectric caps, and at least 5 feet of safety
fuze. Electric detonation methods may be used if available.
Danger zone; 500 yards.
c. Method No. 3 . (i) Fire one howitzer at the others
from' position 200 yards distant. Use HE or HE antitank
shell. Two or more hits on a vital spot should suffice.
(2) Destroy last howitzer and carriage by best means
available.
(3) Enemy salvage of some parts is probable with this
method.
d. Method No. 4 . (i) With tube near zero elevation,
insert four unfuzed incendiary grenades end to end midway
in tube and close breech.
(2) Ignite another incendiary grenade equipped with a
15-second Bickford fuze, toss it in the muzzle, and elevate
tube quickly to its maximum elevation.
(3) Destroy remaining parts by other means. Elapsed
time: 2 to 3 minutes.
61 . PNEUMATIC TIRES. Tires must always be de-
stroyed, even when time is lacking to destroy the remainder
of the weapon or vehicle.
a. Method No. 1 . Ignite an incendiary grenade under
each tire. If used in combination with carriage or vehicle
destruction by explosives, incendiary fires must be well started
before charges are detonated.
b. Method No. 2 . Deflate tires. Damage with ax.
92
pick, or fire from heavy machine gun. Pour gasoline on
tires and ignite.
62. AMMUNITION. Adequate destruction of a full bat-
tery load takes 30 to 60 minutes. See TM 9-1900 and
9-1901 for safety precautions.
a. Method No. 1. (i) Stack ammunition in small piles.
If time permits, remove complete rounds from containers
and propelling charges from cartridge cases.
(2) Stack drums or cans of gasoline around piles. Throw
on any available rags, scrap wood, brush, or other inflam-
mable material to insure a very hot fire.
(3) Pour gasoline on piles, ignite, and take cover.
b. Method No. 2. Unpack complete rounds, stack in
two stacks 3 inches apart, fuzes facing each other. Place
TNT between stacks, at least i pound for each four rounds.
Detonate all TNT simultaneously from cover.
»63. VEHICLES, a. Method No. 1. (Time: r to 2
minutes, with charges prepared in advance and carried in
vehicle. If prepared charges are carried in vehicle, l{eep caps
and fuzes separated from charges until used.) Remove and
empty fire extinguishers. Puncture fuel tanks. Place TNT
charges as indicated in the table below. Insert tetryl non-
electric caps with at least 5 feet of safety fuze in each charge.
Ignite the fuzes and take cover.
Vehicle
Pounds
TNT
Where placed
^2
Against center of engine
block at base of distributor
shaft.
At flange joining transmis-
sion and differential hous-
ing.
Top of tracks at midpoint.
On bogie suspension assembly.
Medium tractor and M5
(Smash generator, start-
ing motor, and carbure-
tor before placing
charges.)
2
1
,1
2
\l
Top of clutch housing. Open
hood to place charge prop-
erly.
Left side of engine, low as
possible.
1
669119°— 15 7 93
b. Method No. 2 . (Time: 5 to 8 minutes.) Remove
and empty fire extinguishers. Puncture fuel tanks. Open
all doors and hatches. Fire on vehicle with artillery, rockets,
or grenades. Aim at engine, suspension, and armament in
that order. If a good fire is started, vehicle may be con-
sidered destroyed.
c. Method No. 3 . Choose appropriate variation.
(1) When vehicle contains enough fuel to insure rapid
burning, use small-arms fire or pioneer tools to puncture in
sequence: crankcase oil pan, radiator tank and core, oil
filter. Start engine and let it race with hand throttle open
full. Remove and empty fire extinguishers. Puncture bot-
tom of gasoline tank and drench tires, cargo, cab interior,
and engine with gasoline in order named. Ignite fuel from
windward side. (Time: 15 to 45 minutes.)
(2) Puncture with small-arms fire or pioneer tools, in
sequence: crankcase oil pan, radiator tank and core, oil filter,
tires. Start engine and let it race with hand throttle open
full. (Time: 5 to 12 minutes.)
(3) With pioneer tools or rifle butt smash or puncture
in sequence: distributor cap and housing, ignition coil, car-
buretor, intake and exhaust manifolds, fuel pump, radiator
tank and core, battery, and fuel tank. If flame and smoke will
give no information to enemy, ignite fuel. (Time: 3 to 5
minutes.)
d. Method No. 4 . Drive to edge of bluff or ravine, let
engine race, and push vehicle over edge. For more thorough
destruction, smash additional vehicles on same pile at bottom.
Note. Whenever practicable, execute the following destruction be-
fore proceeding with other methods of destruction: smash or puncture
generator, starting motor, distributor cap and housing, ignition coil, fuel
pump, fuel tank, crankcase oil pan, radiator tank and core, battery, and
carburetor.
94
INDEX
Paragraph Page
Accuracf in laying 34 53
Accuracy, procedure to insure 21 33
Action, to prepare for 16 16
Action front 14 13
Adjustment of sighting equipment 45~47 , 58
Aiming posts:
Alignment 35 53
Correction for displacement 36 54
Ammunition :
Care 43 56
Checking rounds not fired 20, 26, 27 29,
41, 42
Destruction 62 93
Direct laying 31 45
Handling 43 56
Section 4 4
To prepare 26-28 41
Angle of site. (T« Site, angle.)
Base deflection, to record 21 33
Basic data, recording 20 29
Boresighting 47 59
Breech mechanism 22 37
Destruction 60 91
Cannoneers, to post 9 6
Care and maintenance 48-54 64
Carriage, leveling 47 59
Ceasing fire 38 55
Changes in data during firing 40 55
Chemical attack 55-57 90
Correction for displacement 36 54
Coupling 15 15
Data board, section 44 57
Decontamination 55-57 90
Definitions 3 3
Deflection 21 33
Deflection difference 21 33
Destruction of equipment 58-63 90
Ammunition 62 93
Howitzer '. . . . 60 91
Pneumatic tires 61 92
Sighting and laying equipment 59 91
Vehicles 63 93
Direct laying 29-33 43
One-man, one-sight system 32 49
Two-man, two-sight system 31 45
95
Paragra-ph Page
Direction, to lay for 21 33
Dismounting 11 11
Displacement correction 36 54
Duties in —
Care and maintenance 48-54 64
Firing 19-33 26
Prepare for action 16 16
March order 18 23
Elbow telescope. (3'«« Telescope, elbow.)
Elevation ;
Quadrant 20 29
To lay for 20,22 29,37
To measure 20 29
To set 22 37
Scales, test and adjustments 47 59
End-for-end test 47 59
Errors, reporting 20, 37 29,55
Firing:
Cease. . . 38 55
Change in data 40 55
Procedure 22 37
Resume 39 55
Suspend 39 55
Formation 5 4
Fuze, choice of for direct laying 31 45
Fuze setter 24 40
Fuzes, to set 24, 25 40,41
Gas attack 55-57 90
Grenades ;
Antitank 60 91
Incendiary 61 92
Gunner's quadrant:
End-for-end test 47 59
Use 20 29
Howitzer. (Tes Materiel.)
Inspections and maintenance 48-54 64
After operation 53 78
Before operation 49 65
During firing 52 77
During halt 51 74
During march 50 72
Weekly 54 84
Laying:
Accuracy 34 53
Direct 29-33 43
For direction 21 33
Indirect 19-28 26
96
Paragraph Page
Lead, to determine 31 45
Loading the piece 23 39
Maintenance and care of materiel 48-54 64
March order 18 23
Materiel :
Care and maintenance 48-54 64
Destruction 58-63 90'
Functioning 20 29
Measuring:
Angle of site to mask 20 29
Deflection ; . . . 21 33
Elevation 20 29
Misfires 42 51
Mounting 10 8
Movement of piece by hand 12, 13 12
Optical parts:
Care... 45 58
Destruction 59 91
Panoramic telescope. (See Telescope, panoramic.)
Posts, aiming:
Alignment 35 53
Correction for displacement 36 54
Posting cannoneers 9 6
Posts of cannoneers:
Pieces coupled 8 6
Pieces uncoupled 8, 17 6,20
Prepared for action 17 20
Powder charges:
Destruction 62 93
Replacing increments in rounds not fired 26 41
To prepare 26-28 41
Prearranged fires 20 29
Prepare for action 16 16
Quadrant, gunner's:
Test 47 59
Use 20 29
Quadrant, range 47 59
Rammer, method of using 22,41 37,56
Range:
Determining initial 31 45
Laying for.' 31 45
Setting 22 37
Range card 30, 31 44,45
Range limits in direct laying 33 51
Range quadrant 47 59
Recording base deflection 21 33
97
Paragraph Page
Recording basic data 20 29
References ^ 2
Refer the piece 21 33
Reporting errors 20, 37 29, 55
Scales, azimuth 47 59
Section, howitzer:
Duties. (■5’« Duties.)
Composition 3,4 3,4
Formation 5 4
Mounting, dismounting 10, 11 8, 11
Section data board , 44 54
Section maintenance drill 48-54 64
Sighting equipment:
Boresighting 47 59
Care.... 45 58
Destruction 59 91
Tests and adjustments 47 59
Site, angle of:
Scales 47 59
Setting 22 37
To mask ; 20 29
Squad, howitzer 4 4
Formation 5 4
Posts 6, 7 6
Suspending fire 39 55
Telescope, elbow:
Tests and adjustments 47 59
Use 31 45
Telescope, panoramic, M12:
Care 45 58
Destruction 59 91
Mount 47 59
Tests and adjustments 47 59
Use ■ 21 33
Testing target : . . . . 47 59
Tests, sighting and laying equipment 47 59
Tracking target 31 45
Tractor M5, medium. (X« Materiel.)
Trailer M21. (^See Materiel.)
Trails, shifting 23, 24, 27, 28 39,40,
42, 43
Tube, destruction 60 91
Uncoupling .*. . . 14 13
Unloading the piece 22, 41 37, 56
Vertical displacement 33 51
98