Technical data

TM 9-1005-319-23&P 0003
0003-1
FIELD MAINTENANCE
THEORY OF OPERATION
GENERAL
The 5.56mm M16A2, M16A3, M16A4 rifle and the M4/M4A1 carbine is gas-operated. It fires in the
semiautomatic, full automatic, or burst mode. The weapon has positive locking of the bolt. The firing pin is
part of the bolt carrier assembly and cannot strike the primer until the bolt assembly is fully locked.