The Dirty Bird Industries Nickel Boron Bolt Carrier Group is a substantial upgrade from a standard BGC. Its NiB coating reduces friction on sliding surfaces and prevents carbon build-up making cleaning a much easier task. The NiB coating offers great heat dissipation, allowing reduced wear on the BCG and interacting parts, to further prolong the lifespan of the unit. MIL-SPEC dimensions ensure correct component function and reliability.Features: Machined from 8620 tool steel (carrier) and 9310 carpenter steel (bolt) Forward assist serrations Shrouded firing pin Nickel boron coating inside and out (bolt, carrier, and gas key) Forged MIL-SPEC gas key attached with grade 8 hardware and properly staked. 5.56 NATO bolt is shot peened and magnetic particle inspected MIL-SPEC extractor spring, black extractor insert, Viton O-ring Tool steel extractor Weight 11.52 oz100% MADE IN THE USABacked by the Dirty Bird Industries Lifetime Warranty