FAXON 9310 5.56 BOLT - .125 - NITRIDE
Faxon
$54.99
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.
Warranty: Faxon Firearms products are backed by our Lifetime Guarantee to the original purchaser against defects in materials and workmanship. Warranty service requires an RMA and proof of purchase. Full terms and exclusions:
https://faxonfirearms.com/warranty-privacy-terms/
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Reviews
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5.56 Bolts
I needed to replace a bolt in a well used BCG. For me it’s all about quality, I bought two so I have a spare for my additional rifle.
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Outstand Bolt!
This bolts are great and work really well with Adams Arms piston kit carriers. The AA carriers are cut pretty tight, and I was having issues with the gas rings on different bolts fitting with the AA carrier, but since I usually use a barrel and bolt combo - I never personally realized how easy it was to pair these bolts with AA carriers until recently I was doing a build for a friend. They picked up a brand new run of the mill bolt and it wouldn't seat in the AA carrier. Figuring it was the gas rings, I switched them out - same unfortunate issue. Ended up ordering a Faxon and putting the issue to bed.
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great bolt
i got this bolt along with a barrel headspaced to this bolt. no issues at all with headspacing. extractor was stiff at first chewing up brass a little but this went away after first deep cleaning. 4 stars only because finish is wearing off already after only 500 rounds. other than that awesome product
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So Far So Good
Machining looks top notch, only fired a few mags so far, mainly to make sure it worked. So far it works just as good as any other bolt. Great value for the price