FAXON MATCH SERIES GUNNER PROFILE 11.5" 1:5T PISTOL-LENGTH 338 ARC AR15 BARREL

Rifle Barrels › Match Series › 338 ARC › 11.5″ Gunner, 1:5, Pistol-Length  |  Works with: .750″ gas block • pistol gas tube • 6.5 Grendel/ARC Type 2 BCG (.136) • 5/8x24 muzzle devices • .36 cal suppressors

Why 338 ARC

338 ARC is Hornady’s big-bore AR-15 cartridge, introduced in late 2024: a 6.5 Grendel case necked up to .338. It fires 175 to 215 gr supersonic bullets and a 307 gr Sub-X subsonic, so one short AR-15 can handle hunting, defense, and quiet suppressed shooting.

Subsonic velocity barely changes with barrel length, about 5 fps per inch or less, which is why short 338 ARC barrels make such good suppressor hosts. Supersonic loads gain roughly 25 to 30 fps per inch, so longer barrels pay off for hunting with supersonics.

Go deeper: 338 ARC Guide • RECOIL’s 338 ARC Build • All 338 ARC barrels

Choosing a 338 ARC Twist

SAAMI technically specifies a 1:8 twist for 338 ARC. Faxon offers a 1:5 because it performs better with heavier subsonic bullets in shorter configurations: the extra spin keeps long, heavy projectiles stable at subsonic velocity from a short barrel. RECOIL ran Hornady 307 gr Sub-X subsonics and 175 gr supersonics through a Faxon 11.5″ 1:5 with good results. If you want the SAAMI-spec barrel, choose a Faxon 1:8.

The Gunner Profile and Pistol-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. Pistol-length gas gives a short barrel enough dwell time to cycle reliably, with or without a suppressor.

At 11.5″, 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 1:5 twist.
3. Air gauge: Bore air gauged.
4. Stress relieve: Stress relieved at the blank stage, then qualified true to the bore.
5. Profile, thread, crown: Gunner profile turned, .750″ journal held concentric to the bore, 5/8x24 threads cut, target crown.
6. Chamber: 338 ARC chamber cut and CMM-checked.
7. MPI and nitride: Wet magnetic particle inspected, then salt-bath QPQ nitrided inside and out.
8. Port and extension: .093″ gas port drilled and reamed; NP3 extension torqued to 150 ft-lb, pinned, and 100% headspaced.
9. Mark and inspect: Laser-marked “.338 ARC 1-5T 5R 416R MPI”, then final inspection of the crown, feed ramps, chamber, and threads.

How We Inspect It

Faxon barrels are built to a written control plan, and each run is logged on inspection sheets. Here is what this barrel goes through before it ships.

What Reviewers and Owners Say

This barrel doesn’t have reviews of its own on FaxonFirearms.com yet, so be the first to write one below. Here is what buyers and reviewers say about Faxon’s 338 ARC and Match Series barrels.

Build It Out: Faxon Parts That Fit This Barrel

Compare Faxon Match Series 338 ARC Barrels

Match Series 11.5″ 338 ARC FAQs

What bolt and magazines does 338 ARC use?

A Type 2 Grendel-pattern bolt, such as Faxon’s 6.5 Grendel/ARC Type 2 BCG. Use magazines made or recommended for 338 ARC; guidance varies by load, and Hornady has recommended specific magazines for the 307 gr subsonic.

Which suppressor works with 338 ARC?

A .36 caliber can rated for the cartridge, such as the HARMONIX® ION .36. Always confirm the suppressor’s caliber and pressure rating before mounting it.

1:5 or 1:8 for 338 ARC?

SAAMI technically specifies 1:8, and Faxon’s 1:8 barrels run every factory load. Faxon offers the 1:5 for better performance with heavier subsonic bullets in shorter configurations, so choose it for a short, suppressor-first build.

Do I need a special upper for 338 ARC?

Faxon recommends its 338 ARC Enhanced Forged Upper. Faxon’s 338 ARC barrel extension is custom milled with extended feed ramps for better feeding with heavy subsonic rounds, and the 338 ARC upper’s feed ramps are cut to match that geometry.

What gas block and gas tube does it take?

A .750″ gas block on the 1.9″ journal and a pistol-length gas tube. Faxon’s patented adjustable .750″ block is the recommended pick, especially suppressed. The gas port is .093″, 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 an 11.5-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.