FAXON MATCH SERIES GUNNER PROFILE 12.5" CARBINE-LENGTH 6MM ARC AR15 BARREL

Rifle Barrels › Match Series › 6mm ARC › 12.5″ Gunner, 1:7.5, Carbine-Length  |  Works with: .750″ gas block • carbine gas tube • 6.5 Grendel/ARC Type 2 BCG (.136) • 5/8x24 muzzle devices • .30 cal suppressors

Why 6mm ARC

Hornady developed 6mm ARC for a U.S. Department of Defense group that wanted long-range performance from an AR-15. It necks the Grendel case down to 6 mm and fires long, high-BC bullets in the 103 to 108 gr range that buck wind well past where 5.56 runs out of steam.

It uses the same Grendel-pattern bolt as 6.5 Grendel and runs in a standard AR-15 lower and upper, which makes it one of the most popular ways to build a precision or hunting AR without moving up to an AR-10.

Go deeper: 6mm ARC Barrel Buyer’s Guide • Best 6mm ARC Barrel Length • All 6mm ARC barrels

Why a 1:7.5 Twist

Hornady built 6mm ARC around a 1:7.5 twist so it stabilizes the long 103 to 108 gr match and hunting bullets the cartridge is known for.

Velocity and Barrel Length

Hornady publishes from a 24″ test barrel. Gas-gun loads also run lower than bolt-gun data, so expect your numbers to be lower than the box.

Sources: Hornady factory data and Athlon Outdoors’ 22″ chronograph test. Estimates, not Faxon testing.

The Gunner Profile and Carbine-Length Gas

Faxon’s Gunner profile puts steel where a barrel needs stiffness, at the chamber and under the handguard, and trims it out front, so you get Government-profile durability with close to Pencil-profile handling. Carbine-length gas is the standard system for short and mid-size barrels and cycles reliably across a wide range of loads.

At 12.5″, it is under 16″, so it builds an AR pistol or a registered short-barreled rifle unless a muzzle device is permanently attached to bring the barrel to 16″.

What “Match Series” Means

Match Series is Faxon’s 416-R stainless line. 416-R machines cleanly and holds a consistent bore, and Faxon button rifles it with 5R rifling, five lands with sloped sides instead of sharp-cornered ones, which deforms the bullet less and fouls less. Then the barrel is salt-bath QPQ nitrided inside and out. Nitride is a diffusion treatment, not a plating: it hardens the bore surface and adds corrosion resistance while adding virtually nothing to the dimensions, a few ten-thousandths of an inch, roughly a tenth the width of a human hair. It needs little to no break-in.

How it compares to Faxon’s other lines: the Duty Series is 4150 CMV with the same nitride finish, the hard-use option; the MATCH-X Series takes 416-R further with a honed and lapped bore and an uncoated exterior; and the Combat Series offers classic configurations with chrome-lined bores and manganese phosphate.

What’s in the Box

How It’s Made

1. Drill and ream: The 416-R bar is gun-drilled and pull-reamed.
2. Button rifle: 5R button rifled, right-hand 1:7.5 twist.
3. Stress relieve: Stress relieved at the blank stage, then qualified true to the bore.
4. Profile, thread, crown: Gunner profile turned, .750″ journal held concentric to the bore, 5/8x24 threads cut, target crown.
5. Chamber: 6mm ARC chamber cut and CMM-checked.
6. MPI and nitride: Wet magnetic particle inspected, then salt-bath QPQ nitrided inside and out.
7. Port and extension: .065″ gas port drilled and reamed; NP3 extension torqued to 150 ft-lb, pinned, and 100% headspaced.
8. Mark and inspect: Laser-marked “6MM ARC 1-7.5T 5R 416R MPI”, then final inspection of the crown, feed ramps, chamber, and threads.

What Reviewers and Owners Say

Average ratings, out of 5 stars: 5.0 on FaxonFirearms.com.

Build It Out: Faxon Parts That Fit This Barrel

Compare Faxon Match Series 6mm ARC Barrels

Match Series 12.5″ 6mm ARC FAQs

What bolt and magazines does 6mm ARC use?

The same Type 2 Grendel-pattern bolt as 6.5 Grendel (.136″), such as Faxon’s 6.5 Grendel/ARC Type 2 BCG, and magazines made for 6mm ARC. Not every Grendel magazine feeds 6mm ARC reliably, so use ones built or tested for it.

What is the best barrel length for 6mm ARC?

It depends on the job. 12.5″ is the compact suppressed choice, 16″ is the all-around hunting and carry length, and 20″ to 24″ get the most velocity for long-range precision. Faxon’s 6mm ARC barrel length guide walks through each.

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’s patented adjustable .750″ block is the recommended pick, especially suppressed. The gas port is .065″, reamed to size.

Will it run suppressed and unsuppressed?

Yes. A suppressor adds back-pressure, so Faxon recommends its patented adjustable gas block: tune it for your can and ammunition, then open it back up when you shoot unsuppressed. If you run a lightweight carrier, always pair it with an adjustable gas block.

How is Match Series different from Duty Series and MATCH-X?

Match Series is 416-R stainless with 5R rifling and QPQ nitride inside and out. Duty Series is 4150 CMV with the same nitride finish. MATCH-X is 416-R with a honed and lapped bore and an uncoated exterior. All are made in Greater Cincinnati.

Is the nitride inside the bore?

Yes. Salt-bath QPQ nitride is a diffusion treatment, not a plating, so it hardens the bore and exterior while adding virtually nothing to them: the surface grows by a few ten-thousandths of an inch, roughly a tenth the width of a human hair. It needs little to no break-in.

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

No. It ships with the nickel-Teflon extension installed, torqued to 150 ft-lb, pinned, and headspaced. Gas block, gas tube, and muzzle device are sold separately; the muzzle is threaded 5/8x24.

Is it full-auto capable, and how much heat can it take?

Yes. Like every Faxon nitrided rifle barrel, it is full-auto capable. The barrel is stress relieved, magnetic particle inspected for flaws, and salt-bath nitrided at roughly 1,050°F, so the steel and the nitride are stable far beyond normal firing temperatures. What limits any barrel on automatic fire is heat. A good guideline, drawn from U.S. military guidance for the M4 carbine: about 12 to 15 rounds a minute can be fired indefinitely, and continuous rapid fire should stop at about 150 rounds so the barrel can cool. Short barrels heat up faster than a 16″ rifle barrel, so expect to reach those limits sooner. Push past that and throat wear speeds up, which shortens barrel life. If the barrel smokes or starts to glow, stop: near 1,000°F the steel is approaching the temperature it was nitrided at, where it can begin to soften and the nitride can lose hardness, and military testing has seen M4 barrels fail at about 1,360°F. A hot chamber can cook off a round in as little as 10 seconds, so clear it quickly or keep it pointed in a safe direction. And heat affects accuracy in every barrel: groups open up as it heats. Faxon’s stress relieving and machining keep point of impact from walking, but let it cool before you check zero or shoot for groups.

Is a 12.5-inch barrel legal?

A barrel under 16″ makes the firearm an AR pistol or a short-barreled rifle, depending on how it is configured. Know and follow federal, state, and local laws before you build.

Where is it made, and what is the warranty?

Made in Greater Cincinnati, Ohio, and covered by the Faxon Lifetime Guarantee.

Full-auto heat guidance is general, based on published U.S. military rate-of-fire guidance and steel and nitride data, not Faxon testing; barrel life under automatic fire depends on rate of fire, ammunition, and cooling. Velocity, stability, and energy figures come from published ammunition-maker and independent test data, not Faxon testing; results vary with ammunition, barrel, and conditions. MuzzLok®, HARMONIX®, CORESYNC®, and Flame Fluted® are trademarks of Faxon Firearms. Know and follow all federal, state, and local laws.