AR-15 Bolt Carrier Groups

AR-15 bolt carrier groups in 5.56, 6.8 and 9mm are complete and ready to drop into your upper. The 5.56 and 6.8 bolt carrier groups are offer in a semi auto version, often called the AR-15 carrier and a full auto version, called the M-16 carrier. The M-16 carrier will NOT make your weapon full auto, it just provides a little more weight to the carrier assembly.