DESCRIPTION AND THEORY OF OPERATION
M242 25-MM AUTOMATIC GUN AND
M242 25-MM ENHANCED AUTOMATIC GUN
UNIT AND DIRECT SUPPORT
EQUIPMENT DESCRIPTION AND DATA
EQUIPMENT CHARACTERISTICS, CAPABILITIES, AND FEATURES
a. EXTERNALLY POWERED (EP): An electric motor, located on the bottom and to the rear of the auto gun receiver, drives all the moving parts inside the gun. Ammunition feeding, loading and firing, extraction, and ejection are all done by the motor. The gun does not depend on barrel recoil or expanding gases for operation. The auto gun receiver is solidly attached to a rigid mount and does not recoil when the gun is fired. Only the barrel, breech, and bolt assemblies recoil.
b. SAFE PROTECTION: The firing pin is cocked just before firing to ensure safe operation during the ram cycle. As the bolt turns to lock into the breech, the firing pin tang makes contact and compresses against the firing pin pawl, located on the track. When in the SAFE position, the safety pawl (located next to the firing pin pawl) is raised and prevents the firing pin from riding forward and striking the primer when the bolt completes its turn into the breech. If the weapon is in the FIRE position, the safety pawl is lowered below the path of the firing pin tang, allowing the firing pin to release and strike the primer. The bolt is seared (locked in the "open bolt" position) when the trigger is released. This is accomplished by simultaneously removing voltage to the sear solenoid. The sear pivots into the chain area and captures the chain master link, stopping the bolt and track assembly in the SEAR (rearward) position.
c. QUICK-CHANGE CAPABILITY: The gun can be removed from a mount and another gun installed in a short time. Two persons can remove the automatic gun feeder, barrel assembly, and auto gun receiver quickly.
d. MECHANICAL INTERLOCK MISFIRE/HANGFIRE PROTECTION: The receiver assembly mechanical interlock system stops the gun with the bolt locked in the breech if a round misfires or hangfires. During normal firing, the mechanical interlock system is initiated by the breech moving rearward during recoil, striking the rocker arm located below the right rear side of the breech. This rocker arm moves the operating rod forward (located on the base of the receiver), activating the linkage behind the rear chain guide. When activated, the rear chain guide linkage pivots the sear out of the chain area, allowing the chain safety link to pass and allowing the bolt to extract the spent cartridge. If there is no recoil (as is the case when a round misfires or hangfires), the mechanical interlock system is not activated and the sear captures the chain safety link, locking the bolt in the forward position.
Was this article helpful?