Pave Hawk GAU-21 testing at Edwards
The FN Herstal M3M, designated the GAU-21, is an open bolt system with a barrel life of 10,000 rounds, a cyclic rate of fire of up to 1100 rounds per minute, and reduced recoil over standard .50 caliber weapons due to the use of a soft mount. (U.S. Air Force photo by Brad White)