Faxon Bolt Carrier Groups are Superfinished to reduce friction, increase smoothness of operation, and reduce fouling. Seeing "MIL-SPEC" as just the starting point, include using 9310 tool steel for the bolt, nitriding the assembly to increase surface hardness, decrease resistance and have superior corrosion resistance compared to typical chrome and phosphated bolt carrier groups. All bolts are fully MPI tested to ensure the material is sound and without defects. Bolt lugs are chamfered 45 degrees to ensure reliable action for even the highest pressure hand loads and fast lightweight actions. Gas keys use grade 8 fasteners and are fully staked for a lifetime of service. Product Specifications Category: Bolts & Pistons Series: Gen2 Model: Bolt Carrier Group Caliber: 8.6 Blackout Material: 9310 Steel Finish: Salt Bath Nitride