RISE Armament's RA-1011 AR-15 Bolt Carrier Group is manufactured with the same level of precision and craftsmanship that all RISE products are known for. It features an easy to clean black nitride finish making maintenance, and each piece is individually inspected to ensure the utmost quality. Features: High-strength and easy-to-clean black nitride finishIndividually MPI testedBolt: 9310 MPI testedCarrier: 8620 tool steel heat treated and case hardenedGas key: tool steel - grade 8 hardened fasteners and staked properlyCam pin: 4140 steelExtractor: tool steel – shot peened RISE Armament RA-1011 AR-15 .223/5.56 Black Nitride Bolt Carrier Group RA-1011-BLK