FM 23-45 Basic Field Manual
5
(
a
) Turn cover pin spring up and remove pin,
(
b
) Remove cover.
(2)
Guns of new manufacture
.
(
a
) Remove cotter pin from cover bolt.
(
b
) Place screwdriver blade of combination tool in slot in cover bolt to prevent it
from turning and with a wrench remove the nut.
(
c
) Remove cover bolt, cover catch spring, and fixed and movable plates.
(
d
) Remove cover.
NOTE.—To prevent undue wear, the cover and latch should not be removed except when necessary for cleaning or
replacement of parts.
■11. R
EPLACING GROUPS IN GUN.—In general, the groups are replaced in the gun in
reverse order.
a
. (1)
Guns of early manufacture
.—Replace cover. Insert cover pin and lock it by
turning cover pin spring forward into its seat in trunnion block. Some models have a
cover pin which is locked by inserting and spreading a cotter pin through a hole in the
cover pin.
(2)
Guns of new manufacture
.—Replace cover. Place cover latch spring on bolt and
position the fixed and movable plates. Insert cover bolt into cover hole. Place
screwdriver blade of combination tool in slot in cover bolt to prevent it from turning,
and assemble nut to cover bolt using a wrench until the desired tension is obtained.
Replace cotter pin.
b
. Seat rounded end of latch spring in latch seat, placing hole in spring over pin, bent
side of spring away from latch. Holding spring in place with the fingers, push latch
onto top plate from the rear, free end of the spring to the front, then force the latch
home.
If the spring is allowed to slip from its seat, the latch will not function, and the
spring will jam the latch so that it cannot be removed without breaking.
c
. Screw barrel into barrel extension until barrel locking spring begins to engage in
barrel notches.
d
. Insert barrel and barrel extension into receiver until the forward end of barrel
extension is opposite the rear end of receiver.
e
. Holding barrel extension with one hand, take lock frame in other hand, with index
finger beneath and supporting accelerator. Place claws of accelerator in front of and
against T-lug. Insert front projections of lock frame into slots of barrel extension and
push forward until accelerator turns backward, locking lock frame to barrel extension.
Push down tips of accelerator to insure positive locking.
f
. Push parts into gun, forcing trigger pin inward to clear it from right side plate, and
push forward until a click is heard as trigger pin springs out into its seat in the right
side plate. (If barrel hangs on front barrel bearing, reach forward under jacket and
align it.)
g
. Push cocking lever forward and insert bolt, pushing down on rear end of trigger to
prevent ejector from tripping accelerator.
h
. Insert bolt handle through large opening at rear of slot and push it forward about
1 inch, being sure that collar on handle is inside right side plate.
i
. Push forward on latch and replace backplate.
j
. Hold bolt handle fully back with left hand. Place rim of cartridge in slit in end of
driving spring rod, and turn rod one-quarter turn counterclockwise until slit is
horizontal. This releases driving spring. Allow bolt to go forward.
k
. Make head space adjustment as follows:
(1) Pull bolt to rear about ¾ inch.