Faxon Announces Matched Bolts and Barrels


Faxon Firearms is now offering matched bolts and barrels in both 5.56 NATO and 300 BLK configurations. According to the company, when a customer orders both a barrel and a bolt for the same caliber, the company will “precision match the bolt to the barrel using custom hardened gauging.” For clear identification, the company will laser engrave both indicating they are a matching set.

The company is using 9310 tool steel for the bolt, which is said to be stronger than Carpenter 158 that is frequently used in AR rifle bolts. The bolt carriers can be standard M16 type or the lightweight Gunner series bolt carrier.

Faxon Firearms stated there are no additional charges for this service. However, the company states that this service is applied only to in stock bolts and barrels. The company states the process adds about a week to the delivery time.



  • made from 9310 Tool Steel (said to be stronger than Carpenter No. 158 steel)
  • full Mil-Spec heat treatment
  • shot peened to military specifications
  • Magnetic Particle Inspection (MPI)
  • the back of the lugs have been chamfered for improved reliability
  • spring, silicone insert, Crane O-ring installed
  • QPQ – salt bath nitrided


  • made from S7 Tool Steel
  • full Mil-Spec heat treatment
  • shot peened to military specifications
  • QPQ – salt bath nitrided

“For customers who do not have a set of headspace gauges or a gunsmith available, the factory-matched bolt/carrier and barrel removes all the guesswork from putting together an AR-15,” said Nathanial Schueth, Director of Sales & Product Development. “Further, the laser-engraving ensures that no bolt and barrel are mixed up between rifles.”

Richard Johnson

An advocate of gun proliferation zones, Richard is a long time shooter, former cop and internet entrepreneur. Among the many places he calls home is http://www.gunsholstersandgear.com/.


  • wahooyahoo

    I guess I don’t understand why companies QPQ their 9310 bolts. Do they not understand that the QPQ process will anneal 9310 making it extremely weak? The QPQ isn’t nearly as thick as the standard case hardening.

    • Drew Coleman

      How hot is the QPQ process? Thought that heat treating required very high temps (like red hot)?

      • wahooyahoo

        QPQ is over around 1000 degrees. I meant to say temper, but the steel tempers around 300 degrees. Anything over 400 will soften 9310. Heating is really fancy voodoo magic in the end.

    • Tempering is about two things – temperature and duration. QPQ is typically around 1025 degrees, but is a short duration. As such, the “tempering” is vastly overblown in terms of practical effect on the steel – we’ve done lots of testing and the bolts are stronger than “Mil-Spec.”

  • noob

    guess that KAK should have done that too? (what happened to that article btw?)

    • Havok

      There actually never was an issue with the KAK barrels. It was a article published without any verification and TFB pulled it after speaking to the owner of KAK.

  • DetroitMan

    Part of the magic of the AR-15 is that you don’t have to match the bolt and barrel. I guess everything old is new again.

    • We custom headspace them to the bottom of the spec to get the best accuracy, not just safety.

  • Sianmink

    I’ve never really worried much about the headspacing on an AR rifle.

  • wahooyahoo

    Correct, and I corrected my statement to tempering, which occurs at 300 degrees. After nitriding, the core hardness of 9310 will be roughly 28-32 HRC, which is no longer even close to the MIL-SPEC core hardness requirement. On the MIL-SPEC print for bolts is specifically says “The use of a straight cyanide bath or carbo-nitriding process shall not be permitted”

    • George

      That’s the mil spec for Carpenter 158 bolts not 9310

      • wahooyahoo

        That’s true because the 9310 is not MIL-SPEC, however, the QPQ process has the same end result with the 9310. If you want to have a higher chance of your lugs shearing off or cam pin hole breaking, then take the chance with a QPQ’d 9310 bolt with an extremely soft core. Call up any reputable heat treat facility that performs nitriding and they will confirm that pre-hard 9310(heat treated) will end up with a much softer core hardness after the nitride process.

        • That is an incorrect assumption. Yes, the QPQ process can temper, but its all about duration of the process, which the Salt Bath process is relatively short, not the full tempering cycle. One loses a few points, but that can be made up by harder material prior to QPQ and is further offset by the surface hardening of the QPQ process. One actually WANTS a hard surface and a “softer” core as softer means less brittle.

          • wahooyahoo

            I guess the nitriding company I emailed doesn’t know what they are doing then. They specifically stated they do this on thousands of 9310 bolts in 308 and 223(even though they don’t recommend it) and the core hardness post nitriding is around 28-32 HRC. Yes, you want a relatively soft core, but at some point it becomes too soft and ends up being a failure point.

            Nitriding can last anywhere from 2 to 16 hours and 9310 will temper at 2 hours. Even with a slightly higher core hardness, you still lose the depth of the case hardening. As you said, you want a harder surface, however, a harder surface is only better if it comes with a thicker layer. At the most you’re getting a thousandth of thickness of QPQ, but in the process you’re destroying the case hardening that is approx. .012″ thick. The slightly harder QPQ layer will eventually fail on a bolt and wear much quicker once it has broken into the much softer core.

          • MikeSmith13807

            All I know is Faxon isn’t exactly new to the business of working with metal… I think they’ve established they know what they’re doing. I’ll trust them until I have a reason not to.

          • wahooyahoo

            Do companies like LMT, LWRCI, JP, H&K, Wilson, etc use QPQ bolts? All I’m saying is that just because you can QPQ 9310, doesn’t mean you should.

          • MikeSmith13807

            What I’m saying is that those other companies are firearm companies. Faxon was in the machining business for 33 years before they got in the firearm business. They have a 180,000 SF facility where they make some gun stuff as a side business. I don’t think they decided to offer this product on a whim without being confident it was a good idea.

          • A correct assumption. We make our choices based on testing, not Internet knowledge. 🙂

          • wahooyahoo

            As an engineer with a background in metallurgy, I wouldn’t consider it internet knowledge. I’m not saying the bolts are faulty. I’m saying they likely aren’t as strong as a MIL-SPEC bolt. I would rather trust a company who’s livelihood depends on quality products instead of a company who does this as a side business like you stated. Very few companies posses the ability to not only complete all heat treat and QPQ in house, let alone do proper scientific testing other than a few rudimentary and objective tests.

            I’m sure the bolts work great for a certain time. But science would point to the fact that they are more likely to wear out and fail more quickly than a non QPQ 9310 bolt.

          • Another said “side business”, we did NOT. Firearms is one of our core businesses including making bombs for the air force, parts for NASA, warheads for the Army, and transmission shafts for automotive.

            As we process our bolts, they are stronger and longer lasting the mag phosphate “mil spec” C158. We’ve destructively tested, torture tested, etc prior to any release of a product.

            Our names are on the product which means we take it far more seriously that those with only a brand.

          • wahooyahoo

            No offense, but just because a company can machine and manufacture a part, doesn’t mean they engineered those parts. This is not a slight against Faxon, just a general statement.

            I would love to see the destructive test results from an accredited laboratory if possible. I’m genuinely interested in the results.

          • Mack

            If nitrided bolts were a problem, you would think we would be seeing a lot more broken lugs. I have a full auto 7.5″ with a nitrided bolt with 8000 plus rounds through it, the bolt still looks brand new. Ill keep hammering away with it because it has impressed me.

          • No offense taken, and it is a valid point.

            However, we did actually engineer many of those components. We have patents for firearms, bomb, and automotive designs across a variety of fields.

            Destructive testing is only a small component of the bolt (which we did) The key is repetitive stress testing, which is difficult to replicate outside of rounds through the gun. Suffice to say, we have a nice pallet of spent brass!

  • Matt Shermer

    Is the application in mind for this product lightweight rifles for the weight savers or 1 or less MOA heavy target rifles.

    • Laserbait

      Literally the last paragraph of the article: “For customers who do not have a set of headspace gauges or a gunsmith
      available, the factory-matched bolt/carrier and barrel removes all the
      guesswork from putting together an AR-15,” said Nathanial Schueth,
      Director of Sales & Product Development. “Further, the
      laser-engraving ensures that no bolt and barrel are mixed up between

      • Matt Shermer

        I’m talking about the way the BCG is machined, it looks like it’s optimized for a lightweight rifle because of the machining cuts. Is that for performance improvements or is it just cosmetic?