Overview The RISE Armament AR-15 Bolt Carrier Group (BCG) manufactured with precision and individually inspected to ensure high-level performance. The easy-to-clean black nitride finish offers unmatched strength with each pull of the trigger. Key Features High-strength and easy-to-clean black nitride finish Individually MPI tested Bolt: 9310 MPI tested Carrier: 8620 tool steel heat treated and case hardened Gas key: tool steel - grade 8 hardened fasteners and staked properly Cam pin: 4140 steel Extractor: tool steel - shot peened