RISE Armament AR-10 Bolt Carrier Group - Black Nitride - RISE Armament manufactures its advanced AR-10 bolt carrier group (AR10 BCG) with precision. The .30 caliber BCG is compatible with calibers such as .308 and 6.5 Creedmoor. We also individually inspect each to ensure high-level performance. Be sure to check out all of RISE's bolt carrier group options. Features Made in the USA ; 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;