Faxon Firearms, Bolt Carrier Group, 5.56NATO, Fits AR-15, Titanium Nitride PVD Coated Bolt Carrier and Gas Key, Gold, Salt Bath Nitrided Bolt, Black NEW WARNING Warning WARNING WARNING: This product can expose you to chemicals including machining coolant, machining oil, gun oil, & rust inhibitor, which is known to the State of California to cause cancer. For more information, go to www.P65Warnings.ca.gov. 9310 Tool Steel Bolt Full MIL-SPEC Heat Treatment Shot Peened to MIL-SPEC Magnetic Particle Inspection (MPI) Back of Lugs Chamfered for Reliability Spring, Insert, & "Crane" O-Ring Installed Salt Bath Nitrided Bolt & Carrier TiN PVD Coated Carrier & Gas Key S7 Extractor Superfinished Carrier Body Full Auto Compatible Forward Assist Serrations Product Description Seeing MIL-SPEC as just the starting point, they set out to ensure the best options are available for their demanding customers. Improvements 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 phosphasted 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.