Angstadt Arms AR-15 Bolt Carrier Group, 9MM, Black Finish, Compatible For Use with Both Glock and Colt Style Dedicated 9mm AR-15 Lower Receivers AA09BCGNIT This 9mm bolt carrier group is compatible with both GLOCK and Colt style 9mm AR-15 magazines without any further modifications. It features removable weight for use with the Law Tactical folding stock adapter.