The M174 is a mounted automatic 40mm grenade launcher heavily based on the M1919A4 machine gun and the M79 grenade launcher but fed from an ammo can. It was used in the Vietnam War as a tripod mounted crew-served weapon and as a weapon mounted on various vehicles and aircraft.
The M174 can fire all members of the 40x46mm grenade family with the exception of the M576E2 multiple projectile round and the M1029 crowd dispersal munition.