FAXON MATCH-X SERIES TARGET PROFILE 20" RIFLE-LENGTH 6MM ARC AR15 BARREL

What “Honed & Lapped” Actually Means

A barrel bore starts as a drilled and reamed hole. Reaming leaves a surface finish around 32 Ra, which is good enough for a duty barrel and is where most stainless match barrels stop before the rifling button goes through. On a MATCH-X barrel the reamed bore is honed to 8 Ra, a fourfold improvement, before it is button rifled. The point of honing first is the button: it forms the lands and grooves by displacing steel rather than cutting it, and it can only produce a surface as clean as the one it starts from. A profilometer checks the honed finish and a borescope checks for tool marks before the barrel moves on.

Rifling roughens that surface again, and so does everything that follows. The button cold-works the bore at very high pressure, raising the grain along every land edge; the 1150°F stress relief lets the steel relax and leaves a thin surface oxide; and contouring and chambering release more stress and move the bore by a few ten-thousandths. So after all of that machining is done, the bore is lapped back to 16 Ra, polishing lands and grooves together so the bullet sees one uniform surface from throat to crown. For scale, 16 Ra is the finish class of a ground crankshaft journal or a hydraulic valve spool, and it is smoother than the brushed stainless on a refrigerator door, which runs 25 to 40 Ra.

Why it matters: the smoother the bore, the less copper and carbon it holds, the more uniform the friction on every bullet, and the more consistent the velocity from shot to shot. That shows up as tighter vertical dispersion at distance, a shorter break-in, and a barrel that cleans in a fraction of the passes. Faxon then button-rifles the honed bore with 5R geometry, five lands with sloped sides instead of the sharp corners of conventional rifling, which deforms the jacket less and fouls less again.

The other MATCH-X difference is the outside. Match Series barrels are nitrided; MATCH-X barrels are left as bare 416-R stainless, blasted with S110 media for a uniform matte finish. The bore is plugged and the extension, muzzle threads, and gas port are masked during blasting, so the media only ever touches the exterior. Nothing is added to the steel, so nothing can affect the bore, and the matte stainless surface is thermally stable and easy to keep clean. The trade is that bare stainless wants a wipe of oil after wet or humid use, the same as any stainless match barrel.

What’s Included

How It’s Built and Inspected

1. 416-R stainless bar is gun-drilled and pull-reamed from the chamber end, then honed to 8 Ra. Bore diameter is checked with go/no-go pins, finish with a profilometer, and the surface with a borescope.

2. The bore is button-rifled with a 5R, 1:7.5 right-hand twist (.238″ bore, .244″ groove), then stress relieved at 1150°F for a minimum of four hours. Bore and groove diameters are air-gauged at three points along the length.

3. The blank is chopped, re-centered, and profiled between centers: Target contour, .750″ gas journal held to .0007″, 5/8x24 muzzle threads, and the recessed crown.

4. The 6mm ARC chamber is cut with a go gauge in the machine, verified on a CMM, and borescoped for an even lead. The rifled, chambered bore is then lapped to a 16 Ra finish, bringing lands and grooves to one uniform surface from throat to crown. Every barrel is magnetic-particle inspected.

5. The nickel-Teflon M4 extension is torqued to 150 ft-lb, the gas port is drilled and reamed to .085″, the extension is pinned, and headspace is checked with a 6mm ARC go/no-go gauge. Finally the exterior is blasted with S110 media for the uniform matte finish, with the barrel plugged and the extension, muzzle threads, and gas port masked so the media never touches a sealing or bearing surface.

6mm ARC, By the Numbers

6mm ARC was designed by Hornady in response to a U.S. Department of Defense request for a lightweight AR-15 cartridge that could hit man-sized targets at distances a 5.56 cannot reach. Hornady built it on the 6.5 Grendel case necked down to 6 mm with the shoulder moved back .030″, so long, high-BC bullets seat within the AR-15’s 2.260″ magazine length, specified a 1:7.5 twist to stabilize them, and standardized it with SAAMI at 52,000 psi. Hornady’s own comparison: substantially better ballistics than 5.56 with less drop and less wind deflection, comparable performance to 6.5 Grendel from a wider assortment of bullets, and .308-class reach with substantially less recoil in a 30 to 35 percent lighter package. Faxon was among the first barrel makers to chamber it, and this barrel is cut to that same 1:7.5 specification.

MATCH-X 20″ Target 6mm ARC FAQs

What is the difference between MATCH-X and Match Series?

Both are 416-R stainless with 5R button rifling, a nickel-Teflon extension, and a recessed target crown. MATCH-X adds a bore that is honed to an 8 Ra finish before rifling and brush-lapped to 16 Ra after machining, and leaves the exterior as uncoated, S110-blasted stainless instead of nitride. Match Series is the nitrided, harder-wearing choice; MATCH-X is the smoother-bore, maximum-consistency choice.

What bolt and magazines does 6mm ARC use?

6mm ARC is the 6.5 Grendel case necked down to 6 mm, so it uses a 6.5 Grendel-pattern bolt with a .136″ bolt face and 6.5 Grendel magazines. A standard 5.56 bolt will not headspace and must not be used. The carrier, upper receiver, and buffer are standard AR-15. This barrel is headspaced with a 6mm ARC go/no-go gauge before it ships.

Why a 1:7.5 twist?

Because that is the twist Hornady designed 6mm ARC around and the one in the SAAMI specification. The cartridge exists to push long, high-BC 6 mm bullets, the 103 gr ELD-X, the 105 gr BTHP, and the 108 gr ELD Match, out of an AR-15 magazine, and those bullets need 1:7.5 to stabilize at AR velocities. It also shoots the lighter 58 to 90 gr varmint and CX loads without issue.

What does 6mm ARC do that 5.56 or 6.5 Grendel does not?

In Hornady's words: substantially better ballistics than 5.56 with less drop and less wind deflection, comparable performance to 6.5 Grendel from a wider assortment of bullets, and .308-class reach with substantially less recoil in a package 30 to 35 percent lighter. From Hornady's 24″ test barrel the 108 gr ELD Match leaves at 2,750 fps and is still doing 1,971 fps with 931 ft-lb at 500 yards, which is why the cartridge has become the AR-15 answer for shooters who want to stretch past 600 yards without moving to a large-frame rifle.

Why 20 inches for 6mm ARC?

It is the sweet spot between Hornady's 24″ test barrel and the 16 to 18″ carbines most people build. Hornady publishes its velocities from a 24″ barrel and develops its gas-gun load data in an 18″; a 20″ Target lands close to the published numbers, giving up roughly 75 to 100 fps, while keeping the rifle balanced and the rifle-length gas system's soft, consistent impulse. It is the length for a precision or long-range AR-15; if you want a lighter carbine, this is not that barrel.

What is the Target profile, and what does it weigh?

3.13 pounds. The Target profile is .900″ from the chamber to the gas block and .730″ from the gas block to the muzzle, the stiffest and heaviest contour in the MATCH-X AR-15 line. Stiffness is what keeps groups together as the barrel heats through a string, so it is the right choice for a precision rifle shot from a bipod or bench. It is not the barrel for a lightweight hunting carbine.

Do I need an adjustable gas block?

It is worth having. 6mm ARC factory loads range from 58 gr varmint bullets to 108 gr match loads, suppressor use is common on the cartridge, and the ammunition is loaded to a 52,000 psi gas-gun ceiling that some bolt-gun loads exceed. The Faxon .750″ adjustable block fits the journal, meters the .085″ port to your load, and never puts a screw in the gas path.

Do I need to break in a honed and lapped barrel, and how do I care for it?

Less break-in than a conventional barrel; the honed and lapped 16 Ra bore has already smoothed the tool marks that break-in normally shoots out. Clean after the first range session, then shoot it. Because the exterior is uncoated 416-R stainless, wipe it with a lightly oiled cloth after wet or humid use and run an oiled patch through the bore before storage; that is the only maintenance difference from a nitrided barrel.

Is the barrel extension installed and headspaced?

Yes. The nickel-Teflon M4 extension is torqued to 150 ft-lb, pinned, and the assembly is checked with a 6mm ARC go/no-go gauge before it ships. Install it in a mil-spec upper with a standard barrel nut and a 6.5 Grendel-pattern bolt; no additional headspacing is required, though checking headspace with your own bolt is always good practice.

Faxon Lifetime Guarantee. Covers manufacturing and material defects to the original purchaser. Excludes damage from misuse, neglect, improper installation, non-standard ammunition, or modifications. Bore erosion and finish wear from normal use are not defects. Register your product at faxonfirearms.com/product-registration to expedite service. Full terms: faxonfirearms.com/warranty-privacy-terms.

Dimensions and tolerances are nominal from Faxon engineering drawings. Gas block, gas tube, barrel nut, and muzzle device not included. Barrels are firearm components; verify function and headspace with your bolt before firing, and confirm reliable cycling with your ammunition and gas block setting. Teflon® is a registered trademark of The Chemours Company FC, LLC.

For questions, contact customerservice@faxonfirearms.com.