FAXON DUTY SERIES GUNNER PROFILE 10.5" CARBINE-LENGTH 7.62X39 AR15 BARREL

Rifle Barrels › Duty Series › 7.62x39 › 10.5″ Gunner, Carbine-Length  |  Works with: 7.62x39 BCG • .750″ gas block • carbine-length gas tube • 5/8x24 muzzle devices • .30 cal suppressors

Why a 10.5″ 7.62x39, and Why This Barrel

7.62x39 is the cartridge for a short barrel that still hits hard. It was designed for a 16″ carbine and gives up less than 5.56 does when it is cut short: a 123 gr bullet leaves a 10.5″ at roughly 2,150 fps with about 1,250 ft-lb, more than a 16″ 5.56, and because the bullet is heavy and the cartridge is loaded to moderate pressure it does not depend on velocity to work. That is why the 10.5″ 7.62x39 is the AR pistol and SBR that hunts hogs and deer inside 150 yards, the truck gun that eats the cheapest ammunition on the shelf, and the suppressed .30 that stays short with a can on. It runs in a standard AR-15 upper with a standard carrier; what it needs is a bolt with the larger bolt face, magazines built for the tapered case, and a full-power hammer spring for hard steel-case primers. Faxon makes the barrel and the 7.62x39 M16 BCG to match it.

This is the Gunner profile cut for a .30-caliber bore: a .980″ chamber journal and a Government taper from .675″ to .610″ behind the gas block, where the barrel gets its stiffness, then a .845″ step and a .750″ journal at the block and a .710″ section to the muzzle, where a short barrel takes its heat. The 1:8 twist stabilizes everything from 123 gr ball to 154 gr soft points, the M4-ramped extension feeds the fat case, and the chamber is a true SAAMI 7.62x39 that eats brass and steel alike. Carbine-length gas with a .093″ port is the system that makes a short 7.62x39 reliable with cheap ammunition; owners report it groups near MOA at 50 yards with surplus ball and a red dot and runs hundreds of rounds without a stoppage. For a rifle that needs no stamp, the 16″ 7.62x39 Gunner carries mid-length gas and 200 more fps.

What “Duty Series” Means

Duty Series is Faxon’s 4150 CMV line: the M4/M16 barrel alloy, salt-bath QPQ nitrided inside and out. 4150 carries about 0.50% carbon plus vanadium, which gives it more strength and wear resistance at temperature than 4140, and nitride adds a hard, corrosion-resistant surface to the bore and exterior without plating anything, and it adds virtually nothing to the surface: a few ten-thousandths of an inch, roughly a tenth the width of a human hair. It is the right combination for a barrel that will be shot hard, carried in the weather, and cleaned when there is time. Faxon’s stainless Match Series is the option when you want the precision-barrel formula; the Duty Series is the one to reach for when the rifle has a job.

What’s in the Box

How It’s Made

Every Duty Series barrel is made start to finish in Faxon’s Greater Cincinnati plant, on Faxon’s machines, to Faxon’s prints. This is the routing for this barrel.

1. Drill and pull-ream 4150 CMV bar is gun-drilled, then pull-reamed from the chamber end to a .3015″ bore held to ±.001″, with a 32 Ra maximum finish checked on a profilometer and a borescope pass for reamer marks.
2. Button rifle A carbide button is pulled through from the chamber end to form four grooves, right-hand, one turn in 8 inches, to a .3095″ groove diameter. Bore and groove are air-gauged.
3. Stress relieve and qualify The rifled blank is stress relieved before it becomes a finished barrel, then the OD is qualified true to the bore so every later cut references the same axis.
4. Turn the Gunner profile Muzzle end first: the .750″ gas journal is turned to .7490–.7500″ and checked with a micrometer on every barrel, held within .005″ of the bore, the .710″ forward section is turned true to the same axis, and the 5/8x24 muzzle is threaded and crowned. Then the breech end: the Government taper, the .845″ step, the .980″ chamber journal, and the extension thread.
5. Chamber The 7.62x39 chamber is cut and checked with a headspace gauge; chamber surfaces are held to a 20 Ra finish.
6. MPI and nitride The machined barrel is 100% wet magnetic-particle inspected for surface and near-surface flaws, then salt-bath QPQ nitrided inside the bore and out, hardening the surface while adding virtually nothing to it.
7. Gas port, extension, pin After nitride, the .093″ gas port is drilled and reamed through the .750″ journal, the M4 extension is torqued to 150 ft-lb and pinned, and the barrel is headspaced with a 7.62x39 go/no-go gauge.
8. Mark The Faxon shield and order number are laser-engraved on the chamber journal and “7.62 x 39 1-8T” ahead of the gas block.

What Reviewers and Owners Say

Voted Favorite Aftermarket Barrel by Shooting Sports Retailer every year since 2022 — the Gold Award, the top honor in the category. Faxon also took the Tactical Retailer Gold Award in the same category in 2025. Here is what independent testers and buyers have said about Faxon barrels and this one.

4.5 stars across 4 reviews on FaxonFirearms.com. Elsewhere: Faxon’s 7.62x39 Gunner family averages 4.4 stars across 14 reviews at OpticsPlanet and 4.5 at Brownells.

Build It Out: Faxon Parts That Fit This Barrel

Everything below is made or specified to the same prints this barrel is, so the gas system, extension, and muzzle line up the first time. Pick one from each row and the upper is done.

Duty Series 10.5″ Gunner 7.62x39 FAQs

Is it a 7.62x39 SAAMI chamber, and does it shoot .308 or .311 bullets?

It is a SAAMI 7.62x39 Russian chamber, headspaced with a 7.62x39 go/no-go gauge after the extension is installed, and it feeds and fires standard factory ammunition including brass-case hunting loads and steel-case ball. The bore is cut to .3015″ with a .3095″ groove, which is the American AR standard for the cartridge: it shoots factory 7.62x39 ammunition loaded with .310″ to .311″ bullets at the same pressures and with the same accuracy as .308″ bullets, so there is nothing to sort by. Handloaders can use either diameter.

Why carbine-length gas on a 10.5″ 7.62x39, and how should I set it up?

Because 7.62x39 runs at lower pressure than 5.56 and a 10.5″ barrel gives the port only about three inches of dwell, so carbine-length gas, with the port about 7.7″ from the breech, is the system that catches enough pressure to cycle a heavy .30-caliber bullet reliably with cheap steel-case ammunition, cold, dirty, and suppressed. Faxon reams the port to .093″, which is sized so the barrel runs everything; the trade is that with hot brass-case loads or a suppressor it can run a little fast, and one owner reports exactly that. Set it up with a standard carbine buffer and a full-power spring for steel-case ammunition, step up to an H or H2 buffer if brass ejects forward of three o’clock, and fit the adjustable gas block if the gun will wear a can; it is the one part that makes a short 7.62x39 run right with every load. This barrel needs a carbine-length gas tube.

What is the Gunner profile, and why is the 7.62x39 version different from the 5.56?

Faxon’s hybrid contour: a full-diameter chamber journal and a Government taper behind the gas block where the barrel gets its stiffness, then a step at the block and a slimmer section ahead of it where mass only adds weight. Because a .30-caliber bore leaves less wall than a .22, the 7.62x39 Gunner keeps a .845″ step, a .750″ gas journal, and a .710″ forward section, where the 5.56 Gunner runs a .750″ step, a .625″ journal, and .500″ ahead. That is why it weighs 1.08 lb at 10.5″ and why it takes the most common AR gas block.

What bullet weights does the 1:8 twist stabilize?

Everything the cartridge is loaded with: 122 and 123 gr ball and hollow points, 125 gr hunting bullets, and the 150 to 154 gr soft points. The traditional 1:9.45 twist of the AK stabilizes 123 gr and little else; 1:8 gives the heavier hunting bullets full stability even from a 10.5″ barrel, where the bullet leaves slower and needs the extra spin, and does nothing to hurt accuracy with the light ones. From a 10.5″ the 123 gr loads leave at about 2,150 fps, which is still more energy than a 16″ 5.56 delivers.

What gas block and gas tube does it take?

A .750″ gas block on the 1.9″ journal and a carbine-length gas tube. Faxon makes a .750″ adjustable and a .750″ fixed low-profile block, and a 304 stainless carbine-length gas tube. The gas port is reamed to .093″.

What does 4150 CMV mean?

Chrome-moly-vanadium steel with about 0.50% carbon, the alloy the M4 and M16 barrel specification calls for. The higher carbon and the vanadium give it more strength and wear resistance at temperature than 4140, which matters most on a barrel that will see fast strings and sustained fire.

Is the nitride inside the bore?

Yes. Salt-bath QPQ nitride is a diffusion treatment, not a plating, so it hardens the surface of the bore and the exterior while adding virtually nothing to it: the surface grows by a few ten-thousandths of an inch, .0002–.0004″, roughly a tenth the width of a human hair or about the diameter of a single red blood cell. It also gives the barrel its corrosion resistance and matte black finish.

Does it come with a gas block, gas tube, or muzzle device?

No. It ships with the black-oxide M4 extension installed, torqued, pinned, and headspaced. Gas block, gas tube, and muzzle device are sold separately; the muzzle is threaded 5/8x24.

Will it work with a suppressor?

Yes. The 5/8x24 muzzle takes any .30-cal direct-thread can or 5/8x24 mount, and a short 7.62x39 suppresses well, but carbine gas on a 10.5″ is the system a can over-gasses most, so the adjustable block is the part to buy with the suppressor. For a gun that runs suppressed most of the time, pair it with the Faxon .750″ adjustable gas block so you can bring the gas down.

What else do I need to build a 7.62x39 AR-15?

Three things beyond a standard AR-15 build. A 7.62x39 bolt: the case head is .445″ against .378″ for 5.56, so the bolt face has to be cut for it, and a 5.56 bolt will not close on the round. Faxon’s 7.62x39 BCG or bolt is the match for this barrel. 7.62x39 magazines: the case is steeply tapered, and magazines built for the cartridge, with the curve and feed lips to match, are the difference between a gun that runs and one that does not; standard 5.56 magazines will not feed it reliably. A full-power hammer spring: steel-case military ammunition uses hard primers, and a lower with a light trigger spring will light-strike them. Gas block, gas tube, and handguard are the same parts any 10.5″ carbine-gas AR-15 uses.

Can I shoot steel-case ammunition through it?

Yes. The chamber and the nitrided bore are built for it, and it is what most of this barrel’s owners feed it. Steel-case ammunition is dirtier than brass and its bimetal-jacket bullets wear a bore faster than copper-jacketed ones, which is where the QPQ nitride earns its keep: the hardened bore surface resists that wear far better than a bare chrome-moly barrel. The one thing to plan for is primers: most steel-case 7.62x39 uses hard military primers, so run a full-power hammer spring. Brass-case hunting ammunition shoots more accurately and is the choice for deer season.

How fast does 7.62x39 leave a 10.5″ barrel?

Roughly 2,100 to 2,200 fps with 123 gr ammunition, depending on the load, or about 200 fps less than a 16″. That is still about 1,250 ft-lb, more than a 16″ 5.56 makes, and because the bullet is heavy it keeps hitting hard where a short 5.56 has already gone quiet: soft points expand reliably inside 150 yards, which is the working range of a 10.5″ 7.62x39 on hogs and deer.

Can I put a 10.5″ barrel on my AR-15?

A barrel under 16″ makes the firearm either a pistol or a short-barreled rifle under federal law. Build it on a lower that has only ever been a pistol, or on a lower registered as an SBR with an approved Form 1 or Form 4, and check your state law before you buy. Faxon cannot advise on your specific configuration.

Is the gas journal dimpled for set screws?

No. The journal ships round so any .750″ low-profile, clamp-on, or pinned gas block fits. A set-screw block holds on the nitrided journal when its screws are torqued with thread locker; if you want dimples, mark them through the block’s screw holes and drill.

Where is it made, and what is the warranty?

Made in Greater Cincinnati, Ohio, from bar stock to finished barrel, and covered by the Faxon Lifetime Guarantee.

Dimensions are from the Faxon engineering print and inspection sheets for this SKU; weight is nominal. Gas block, gas tube, and muzzle device sold separately. Owner reviews are quoted as written from FaxonFirearms.com product reviews; press quotes link to their sources. Award: Shooting Sports Retailer Choice Awards, Favorite Aftermarket Barrel, Gold. Covered by the Faxon Lifetime Guarantee.