FAXON MATCH SERIES GUNNER PROFILE 6" 1:5T PISTOL-LENGTH 300 BLK AR15 BARREL

Rifle Barrels › Match Series › 300 BLK › 6″ Gunner, 1:5, Pistol-Length  |  Works with: .750″ gas block • pistol gas tube • 5.56/300 BLK BCG • 5/8x24 muzzle devices • .30 cal suppressors

Why a 6″ 300 Blackout Barrel

300 Blackout was designed to do its work from a short barrel, and it burns most of its powder in the first several inches. That is why it is the cartridge people build the smallest suppressed AR pistols and SBRs around. The 6″ is the size-first choice: the shortest overall length, the lightest barrel, and a gun that still fits in a backpack with a suppressor mounted.

Be clear about the trade. Subsonic ammunition gives up velocity at every inch you cut, and from a 6″ barrel most 190 to 220 gr subsonic loads land in the high 900s fps. That is still plenty for solids and for most training and practice loads, but expanding subsonic hunting bullets need a minimum impact speed to open reliably; Hornady lists 900 fps for its 190 gr Sub-X. If you plan to hunt with expanding subsonics, the 7.5″ or 9″ Match 1:5 gives you more margin. Supersonic loads lose more velocity than subsonics as the barrel shortens, so if supers are the main diet, go longer. Faxon’s 300 Blackout Barrel Buyer’s Guide lays out length-by-length velocity so you can pick the right one.

Why a 1:5 Twist

Most 300 Blackout barrels are cut 1:8 or 1:7. That works for typical lead-core subsonic bullets, but the longest projectiles, 220 to 240+ gr monolithic solids designed for subsonic terminal performance, need more spin than a 1:8 gives them at 1,000 fps. Some makers recommend 1:5 only for their heaviest solids, because an understabilized bullet can yaw and strike a suppressor baffle.

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. The barrel extension is nickel-Teflon (NP3) coated for lubricity and corrosion resistance.

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. For a short, fast-twist 300 Blackout, the Match Series formula, stainless plus nitride, is the one shooters buy most.

What’s in the Box

How It’s Made

1. Drill and ream: The 416-R bar is gun-drilled and pull-reamed to .3015″.
2. Button rifle: 5R button rifled, right-hand 1:5 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 within .005″ of the bore, 5/8x24 threads cut, target crown.
5. Chamber: 300 Blackout chamber cut and CMM-checked.
6. MPI and nitride: Magnetic particle inspected, then salt-bath QPQ nitrided inside and out.
7. Port and extension: .125″ gas port drilled; NP3 extension torqued to 150 ft-lb, pinned, and 100% headspaced.
8. Mark and inspect: Laser-marked “.300 BLK 1-5T,” then final inspection of the crown, feed ramps, chamber, and threads.

What Reviewers and Owners Say

Faxon’s 6″ and 7.5″ Match Series 1:5 barrels share the same recipe, and dealers list them together. Here is what buyers have said about them.

Average ratings, out of 5 stars: 5.0 on FaxonFirearms.com; 4.8 at OpticsPlanet (6″ and 7.5″ Match 1:5); 5.0 at Brownells (Match 300 BLK Gunner family).

Build It Out: Faxon Parts That Fit This Barrel

A 6″ 300 Blackout is usually a suppressed build, so start with the gas system. The adjustable block lets you run it soft with the can on and still cycle without it.

Compare Faxon’s Short 300 Blackout Barrels

Not sure which length? The 300 Blackout Barrel Buyer’s Guide compares velocity, twist, and suppressor use by length.

Match Series 6″ 1:5 300 Blackout FAQs

Why does a 300 Blackout barrel need a 1:5 twist?

It doesn’t for every bullet, but it covers all of them. A 1:8 stabilizes typical lead-core subsonics; the longest 220 to 240+ gr monolithic solids are marginal or unstable in a 1:8 at subsonic speed and can yaw into a suppressor baffle. A 1:5 stabilizes those solids with a wide margin and still runs 110 to 125 gr supersonics, so you are not locked into one ammunition.

Is 6 inches too short for subsonic 300 Blackout?

For most uses, no. Expect most 190 to 220 gr subsonic loads to land in the high 900s fps from a 6″ barrel. That is fine for solids, training, and practice ammunition. Expanding subsonic hunting bullets need a minimum impact speed (Hornady lists 900 fps for its 190 gr Sub-X), so for hunting with expanding subsonics the 7.5″ or 9″ Match 1:5 gives more margin.

What gas block and gas tube does it take?

A .750″ low-profile gas block no longer than 1.000″, because the gas journal is 1.031″ long, and a pistol-length gas tube. Faxon’s patented adjustable .750″ block (GBA-LP-750-3) is 1.000″ long and fits. The gas port is .125″.

Will it run suppressed and unsuppressed?

It is set up for suppressed use. A suppressor adds back-pressure, and short 300 Blackout pistols are sensitive to gas, ammunition, and buffer weight. Faxon recommends the adjustable .750″ gas block so you can tune for your can and ammunition and open it back up unsuppressed. If you run a lightweight carrier, always pair it with an adjustable gas block.

What bolt carrier group do I need?

300 Blackout uses the standard 5.56 bolt face, so any quality AR-15 BCG works, including Faxon’s Gunner Lightweight BCG, which is 300 BLK compatible. Use magazines you have marked for 300 BLK to avoid mixing ammunition.

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.

What is 5R rifling?

Five lands instead of the usual six, with sloped sides instead of square corners. The bullet is deformed less as it engages the rifling, and there are no sharp corners for fouling to collect in, so the bore cleans more easily.

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 M4 extension installed, torqued to 150 ft-lb, pinned, and headspaced with a 300 BLK go/no-go gauge. 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, not just this one: as it heats up, groups open up and point of impact can shift, so let it cool before you check zero or shoot for groups.

Is a 6-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 and stability figures are estimates from published data and the Miller stability formula, not Faxon testing; results vary with ammunition, barrel, and conditions. MuzzLok®, HARMONIX®, and CORESYNC® are trademarks of Faxon Firearms. Know and follow all federal, state, and local laws.