Faxon 5.56 9310 Bolt Nitride Blk

The Faxon 5.56 9310 Bolt Nitride Blk is a premium drop-in replacement bolt carrier built for shooters who demand reliability beyond standard military spec. Faxon starts with 9310 tool steel—a material choice that separates quality AR-15 components from budget alternatives—then applies salt bath nitriding to harden the surfaces and resist corrosion far more effectively than traditional phosphate finishes. Whether you're running a precision rifle, a duty gun, or a hand-loaded precision build, this bolt is engineered to handle the job without compromise.

The engineering details matter. The bolt lugs are chamfered at 45 degrees to promote smooth feeding and reliable lockup, even under high pressure loads or in tight, lightweight actions where tolerances are unforgiving. The extractor is machined from S7 tool steel and incorporates a spring, silicone insert, and o-ring for consistent, repeatable function across variable ammunition and conditions. Every bolt is subjected to magnetic particle inspection (MPI) before it leaves the factory—a non-destructive test that catches internal material defects that visual inspection cannot.

This isn't a guessing game or a cost-cutting compromise. Faxon treats MIL-SPEC as a baseline, not a ceiling. You get full military heat treatment, shot peening per spec, and nitriding that adds measurable hardness and corrosion resistance in one package. For AR-15 shooters building a rifle they intend to keep running for years—through training cycles, competitions, or the field—upgrading to a purpose-built bolt like this pays dividends in reliability and longevity.