Nickel Boron, mil-spec assembly with bolt, bolt carrier, and firing pin. Ready to drop into the rifle or carbine upper of your choice. Features a Nickle Boron self lubricating finish for increased wear resistance, surface strength and durability, and an extractor booster to ensure reliable cycling during rapid semi-auto or full-auto fire (tested full-auto 2/10/13).
Each assembly is magnetic particle inspection tested to ensure its free from imperfections that can lead to premature failures. Properly staked gas key prevents gas leakage that can lead to short stroking. Available in .223/5.56mm, .300 Blackout ONLY... Staked screws, nickel boron exterior with chrome interior for bolt and cam pin.