FAXON DUTY SERIES GUNNER PROFILE 16" MID-LENGTH 7.62X39 AR15 BARREL

Rifle Barrels › Duty Series › 7.62x39 › 16″ Gunner, Mid-Length  |  Works with: 7.62x39 BCG • .750″ gas block • mid-length gas tube • 5/8x24 muzzle devices • .30 cal suppressors

Why a 7.62x39 AR-15, and Why This Barrel

The cartridge is the reason. 7.62x39 is the most-produced centerfire rifle round in the world, which makes it the cheapest .30 caliber you can shoot, and it does real work: a 123 gr soft point at 2,350 fps is a proven deer and hog load inside 200 yards, and steel-case ball costs less than 5.56. An AR-15 chambered for it shoots it better than the rifle it was designed for, with a crisp trigger, a free-float handguard, a flat-top for an optic, and a bore that is held to the same dimensions as a 5.56 match barrel. What a 7.62x39 AR needs to run right is a barrel that feeds the tapered, steeply shouldered case, a bolt with the larger bolt face, and magazines built for the cartridge. Faxon makes the first two; the 7.62x39 M16 BCG is the one to pair with this barrel.

This is the Gunner profile cut for a .30-caliber bore: a Government taper from .675″ to .610″ behind the gas block with a .845″ step at the block where the barrel gets its stiffness, a .750″ gas journal, and a taper to .625″ ahead of the block where diameter only adds weight, so the finished barrel is 1.48 lb with a full-length handguard’s worth of stiffness. The 1:8 twist stabilizes the 150 gr hunting bullets the AK’s twist never could, the M4-ramped extension feeds the fat case, and the chamber is a true SAAMI 7.62x39 that eats brass and steel alike. Mid-length gas is what sets it apart from the rest of the market: a .093″ port 9.7″ from the breech cycles at lower pressure than carbine gas, which is why owners describe it as soft and reviewers run hundreds of rounds of mixed steel-case through it without a stoppage. For a shorter build, the 10.5″ 7.62x39 Gunner carries carbine gas; for a rifle that is done, the complete 16″ 7.62x39 upper is built on this barrel.

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 Gunner taper ahead of it 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.

5.0 stars across 10 reviews on FaxonFirearms.com; 4.7 stars across 6 at Primary Arms. 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 16″ 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 mid-length gas on a 7.62x39, and what buffer should I run?

Most 7.62x39 AR barrels use carbine-length gas because the cartridge runs at lower pressure than 5.56 (about 45,000 psi against 62,000) and a port close to the chamber is the easy way to guarantee cycling. Faxon puts the port at mid-length instead, about 9.7″ from the breech with six and a half inches of barrel past it, and reams it to .093″, larger than the .081″ on its 5.56 mid-length barrels, to make up for the lower pressure. The result is the same thing mid-length does for a 16″ 5.56: a softer, longer push on the carrier, less wear on the bolt lugs and extractor, and a rifle that stays flatter between shots. It cycles brass-case and steel-case ammunition with a standard carbine buffer and spring; if brass ejects hard at two o’clock, step to an H buffer. This barrel needs a mid-length gas tube.

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

Faxon’s hybrid contour: full diameter where the barrel gets its stiffness (the chamber journal and the body behind the gas block) and tapered ahead of the block where mass only adds weight. Because a .30-caliber bore leaves less wall than a .22, the 7.62x39 Gunner keeps the same Government taper behind the block but a .845″ step and a .750″ gas journal, where the 5.56 Gunner runs a .750″ step and a .625″ journal. That is why it weighs 1.48 lb at 16″ against 1.37 lb for the 5.56 Gunner, 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 from a 16″ barrel and does nothing to hurt accuracy with the light ones. From a 16″ the 123 gr loads leave at about 2,350 fps, which is .30-30 performance from a magazine-fed AR.

What gas block and gas tube does it take?

A .750″ gas block on the 1.9″ journal and a mid-length gas tube. Faxon makes a .750″ adjustable and a .750″ fixed low-profile block, and a 304 stainless mid-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 7.62x39 runs at lower pressure than 5.56 and mid-length gas taps it farther from the chamber, so a suppressed 16″ 7.62x39 is one of the softer-shooting, cleaner-running AR combinations there is. For a rifle 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 rifle 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 16″ mid-length 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 from Hornady, Federal, and Winchester shoots more accurately and is the choice for deer season.

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.