FAXON 9310 5.56 BOLT - .125 - NITRIDE
Faxon
Faxon 9310 5.56 Bolt (.125) – Nitride
Category: Rifle Parts
Platform: AR15
Series: Bolts
Caliber/Cartridge: 5.56 NATO
SKU: FF556BCNITRIDE | UPC: 816341020863
MSRP: $56.00
The Faxon 9310 5.56 Bolt (.125) – Nitride is a high-quality replacement bolt for AR-15 platforms, engineered for reliable function and long service life. Seeing “MIL-SPEC” as just the starting point, Faxon uses 9310 tool steel, tight process control, and enhanced finishing to deliver a bolt you can trust.
Each bolt is Magnetic Particle Inspected (MPI) to help ensure the material is sound and free from defects. The bolt is treated with salt bath nitride to increase surface hardness, reduce resistance, and provide excellent corrosion resistance compared to typical phosphate finishes. Bolt lugs are chamfered to promote reliable cycling— even with high-pressure loads and fast actions.
The extractor is made from S7 tool steel and is fully heat-treated and shot-peened. The extractor system is assembled with a spring, silicone insert, and “Crane” O-ring to support consistent extraction.
Detailed Specifications
Bolt
- 9310 Tool Steel Construction
- 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
Extractor
- S7 Tool Steel Construction
- Fully Heat Treated
- Shot Peened per MIL-SPEC
Frequently Asked Questions
What does “.125” refer to?
“.125” refers to the bolt face depth specification commonly used in 5.56/.223 AR-15 bolts. Always confirm compatibility with your barrel.
Is this bolt MPI tested?
Yes. Faxon bolts are MPI tested to help ensure material integrity and quality.
Why nitride instead of phosphate?
Salt bath nitride increases surface hardness and corrosion resistance while reducing friction—often improving smoothness and ease of cleaning.