Bolt carrier groups are available aplenty, but few could meet the exacting standards for performance and value that Faxon Firearms strives for. Seeing "MIL-SPEC" as just the starting point, Faxon set out to ensure the best options are available for the most demanding customers.  Improvements include using 9310 tool steel for the bolt, which is stronger and nitriding the assembly to increase surface hardness, decrease resistance, and have superior corrosion resistance compared to typical chrome and phosphate 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. Extractors are S7 Tool Steel. From there, the extractor is sprung using the spring, o-ring, and silicone insert. Bolt: Magnetic Particle Inspection (MPI) Back of Lugs Chamfered for Reliability Spring, Insert, & "Crane" O-Ring Installed Full MIL-SPEC Heat Treatment   Extractor: S7 Tool Steel Construction Fully Heat Treated Shot Peened Per MIL-SPEC Black Oxide to Match Bolt   Palmetto State Armory is the one-stop shop for the best selection of parts and accessories for the Modern Sporting Rifle enthusiast.