Battle Arms Development Bolt Carrier Group, 9mm, Nitride Finish, Black BAD-BCG-9MM Enhanced 9mm Blowback AR-15 Bolt Carrier Group is compatible with both COLT and GLOCK magazine configurations. Features reliable AR-15 style extractor claw with O-Ring and spring and broad trigger compatibility with ramped bottom geometry. Charging handle interfaces directly on bolt carrier surface that can withstand vigorous pulling force without the worry of shearing off the carrier key. Reinforced firing pin is held in place with standard firing pin cotter pin.