Faxon Firearms 9310 Steel 5.56 NATO MPI Nitride - AR-15 Bolt

Your AR-15 is only as reliable as its bolt. The Faxon 9310 5.56 NATO bolt treats MIL-SPEC as a floor — pairing 9310 tool steel with MPI inspection, salt bath nitride, and chamfered lugs to deliver a drop-in replacement that cycles cleanly and cleans up fast.

The Faxon 9310 5.56 NATO Bolt is a high-quality AR-15 replacement bolt machined from 9310 tool steel with a salt bath nitride finish, designed for reliable function and extended service life on standard 5.56/.223 platforms.

Four qualities set this bolt apart from standard replacements. 9310 tool steel is fully heat treated and shot peened to MIL-SPEC, producing a bolt body with the strength and fatigue resistance needed for high round counts. Magnetic Particle Inspection (MPI) is performed on each bolt to verify material soundness and catch any internal defects before the bolt reaches your rifle. Salt bath nitride increases surface hardness and corrosion resistance while reducing friction compared to phosphate finishes, making both cycling and cleaning noticeably smoother. Chamfered lug geometry supports reliable feeding and extraction even under higher-pressure loads or with fast-cycling gas systems.

Compatible with mil-spec 5.56 NATO and .223 Rem AR-15 barrels. Extractor assembled with spring, silicone insert, and Crane O-ring for consistent extraction.

9310 tool steel bolt, S7 tool steel extractor, both fully heat treated and shot peened. Salt bath nitride finish throughout.

Ideal for AR-15 duty rifles, high-volume training platforms, precision builds, and as a quality spare in any serious shooter's kit.

By Faxon Firearms. Standard Faxon warranty applies.