Faxon Firearms Type 2 Bolt Carrier Group FF65GBCGCNITRIDE for 6.5 Grendel, 6mm ARC, and 22 ARC. Constructed from 9310 tool steel and finished in Salt Bath Nitride. All bolts MPI tested to ensure material integrity. Bolt lugs are chamfered 45 degrees for reliable action under high-pressure loads and fast cycling. Faxon BCGs are fully auto-rated and designed to be compatible with modern AR-15 platforms and multi-stage triggers. Gas keys use Grade 8 fasteners and are fully staked. Not compatible with Faxon 7.62x39 barrels. This item is AR-15 compatible and suitable for standard AR-15 builds.