M2/M3 BRADLEY FIGHTING VEHICLE: TURRET - OD1609 LESSON 1/TASK 1
Coax Machinegun. The coax machinegun is gas operated and belt fed and feeds
from the open bolt position.
The barrel is air cooled and the rate of fire is
controlled by three gas regulator settings.
Regardless of bolt position, the
feeder cover can be opened or closed without damage to the feeder cover or ammo.
A trigger sear releases the operating rod and bolt assembly.
The bolt strips a
round from the belt in the feed tray and stops when the round is fully chambered.
The operating rod forces locking lugs into the receiver.
Then the firing pin
strikes the primer. Burning gases go from the barrel through the gas port to the
gas piston at the front end of the operating rod.
Gas pressure forces the
operating rod back which retracts the firing pin, raises the locking levers, and
removes the spent case. As the bolt moves to the rear, the spent case is ejected
and the live round moves into the feed tray. The bolt continues to the rear until
it strikes the buffer assembly.
The cycle is repeated as long as the trigger is
Coax Machinegun Feed System. Eight hundred rounds of ammo are stored in the
ammo can, which is behind the coax machinegun located on the right side of the
turret. The ammo is in a belt held together by links. The belt feeds through the
forwarder, feed chute, feed tray, and then to the coax machinegun. The projectile
is fired through the barrel.
The links and expended casings eject into a plenum
chamber around the weapon. A sensor detects when the last rounds are about to be
fired, stopping firing.
This leaves the end of the belt in position for easy
reloading. The reloader can link a new belt to the old belt. In emergencies, the
gunner may continue firing by overriding the automatic shutoff.
Coax Machinegun Mounting.
The coax machinegun is rigidly mounted into the
front cradle assembly by two lugs mounted on the receiver. The rear of the coax
machinegun is secured to the rear mount on the 7.62mm rotor.
Turret Ventilation System. When one of the weapons is electrically operated,
toxic gases from the coax machinegun and 25mm gun are vented automatically. When
guns are manually fired, fans on the right side of the rotor can also be manually