TM 9-2350-230-12, C10,
TABLE 3-8. CHECKING AND ADJUSTING TIMING - CAL. .50 MACHINE GUN, M2, HB
STEP
PROCEDURE
FIG/ITEM
1
2
Cock machine gun. (Retract bolt assembly to rear position and slowly
release to forward position. )
3
Raise extractor
4
Retract bolt sufficiently to insert NO FIRE (0. 116-inch) gage between
trunnion block and barrel extension group. Release retracting slide
handle.
5
Depress the trigger. The firing pin SHOULD NOT RELEASE. In the
event it does release repeat steps 2 and 3.
WARNING Do not attempt to remove back plate unless the bolt
is in forward position. Do not attempt to cock machine gun with-
out the back plate assembled to machine gun.
6
Remove back plate
7
Screw the timing adjustment nut all the way down (counterclockwise)
8
Place the FIRE (0. 020-inch) gage between trunnion block and barrel
extension group. Release retracting slide handle.
9
Attempt to release firing pin by lifting up on rear end of trigger lever
13-12/C
10
Screw up (clockwise) on timing adjustment nut one click at a time and
13-12/C
attempt to release firing pin after each click until the firing pin does
release. When the firing pin does release move the adjusting nut two
more clicks clockwise (up).
11
Replace back plate assembly
12
Repeat steps 2 through 5. The firing pin SHOULD NOT RELEASE.
13
Repeat steps 2 and 3.
14
Place FIRE gage between trunnion block and barrel extension and attempt
to release firing pin by pressing the trigger. The firing pin SHOULD
RELEASE.
NOTE If proper timing adjustment cannot be obtained, notify
organizational maintenance personnel.
3-20