Automatic Operation
Replace Barrel Group
If automatic firing is desired, the gun must be set for
To replace the barrel group, pull the retracting slide
automatic operation. To do so, you must ensure the bolt
handle to the rear. Do so until the lug on the barrel
latch release is depressed and locked down. That is done
locking spring is visible through the 3/8-inch hole in the
by turning the buffer tube sleeve. The bolt latch release
right sideplate. (See fig. 13-36,) Again, insert the
lock is rotated to engage the bolt latch release, locking
smallest loop of a .50-caliber link, or suitable spacer,
it down. (See view A of fig. 13-36 again.)
between the trunnion block and barrel extension.
When the bolt latch release is locked down, the bolt
Screw the barrel all the way into the barrel
latch assembly remains in its up position. Thus, when
extension. Then, and this is important, unscrew the
the bolt recoils, it is automatically free to return forward
barrel two notches. Remove the link and close the cover
into the battery.
group. That completes the general assembly of the
To fire the .50-caliber BMG in automatic, (1) lock
.50-caliber BMG.
the bolt latch release down and (2) depress the trigger.
Short bursts are generally recommended, rather than
OPERATING THE .50-CALIBER BMG
sustained firings.
The safest and best way to operate the .50-caliber
Loading Operation
BMG is to follow established procedures. In doing so,
The .50-caliber BMG is loaded manually. This
you prevent damage to the gun and injury to yourself
involves placing an ammunition belt into the receiver of
and others. The basic operating procedures involve the
the gun. Ammunition for the .50-caliber BMG comes
following steps:
prebelted and is shipped in a standard .50-caliber
1. Loading
ammunition box.
2. Half-loading
To load the gun, open and remove the lid on the
ammunition box. Then open and raise the cover group
3. Full-loading
on the gun (fig. 13-47). Insert the double-loop end of the
4. Unloading
ammunition belt into the feedway of the receiver. Ensure
the first cartridge is held by the belt-holding pawl. Close
Semiautomatic Operation
the cover group on the gun and make sure it is latched
securely.
If single-shot firing is desired, the gun must be set
If two personnel are operating the .50-caliber BMG,
for semiautomatic operation. To do so, you must ensure
the assistant gunner loads the ammunition belt. The
the bolt latch release is in the up position (or not locked
gunner performs the next two operations-half-loading
and full-loading.
down). (The bolt latch release can be seen in view A of
fig. 13-37.)
Half-Loading Operation
When the bolt latch release is up, the bolt latch
assembly is depressed. In this position, the latch
Half-loading is a term associated with the
assembly can engage notches on top of the bolt when it
.50-caliber BMG. It can be compared to feeding.
(the bolt) is to the rear. Thus, when the bolt recoils after
Feeding is the first of eight steps in a cycle of operation.
around is fired, it remains locked to the rear.
It places a round in the receiver just to the rear of the
receiver. Do not confuse loading the .50-caliber BMG
Depressing the bolt latch release raises the latch
(described earlier) with half-loading. The two
assembly. The assembly disengages from the notches on
operations are different.
top of the bolt. That allows the bolt to be driven forward
Half-loading the gun is done after the ammunition
into the battery.
belt is installed and the cover group closed. To half-load
To fire the .50-caliber BMG when set for
the gun, the gunner grasps the retracting slide handle,
semiautomatic, (1) depress the bolt latch release and (2)
pulls it smartly to the rear, and releases it. At this point,
depress the trigger. These two actions must be done for
two things can occur. What happens depends on whether
each round fired.
the gun is set for automatic or semiautomatic fire.
13-26
