CENTURION ARMS 6MM ARC BARREL!

Now Available: Centurion 12.5” 6mm ARC Barrels – Proven Accuracy, Compact Performance

We’re excited to announce that the Centurion 12.5" 6mm ARC barrels are now officially in stock and available at Ally Munitions.

If you’ve been waiting on a premium short-length 6mm ARC option—this is the one to grab.

Why the Centurion?

The Centurion barrel offers the perfect blend of precision and portability. Built from 416R stainless and finished with factory-polished M4 feed ramps, it's designed to deliver consistent sub-MOA performance in a compact 12.5" RECCE profile.

Here’s what you get right out of the gate:

• Factory-polished feed ramps for smoother cycling

• Midlength gas system for optimized dwell time and recoil impulse

• Headspaced bolt and gas tube included — you're ready to drop it into a build

• .750" gas journal with alignment notch — compatible with most standard or MK12-style gas blocks

• Threaded 5/8x24, ready for your muzzle device or suppressor

• Gas port size of .082" for balanced performance

Tested. Trusted. Accurate.

Our test sample of this barrel exceeded expectations. It grouped well under 1 MOA with multiple factory loads:

• Hornady 80gr ELD-VT: consistently sub-MOA

• Hornady 108gr ELD Match: best overall accuracy

• Other factory loads: ran smoothly with reliable precision

If you're building a compact precision AR that punches above its size—this barrel delivers.

The Ally Munitions Standard

You already know the deal—Better Comes Standard. Every barrel that hits our shelves is individually inspected and documented. If you're curious about how our inspection process works, check out our full write-up in the latest blog post.

Build It Right

Pair this barrel with one of our top-tier gas blocks, bolt carrier groups, or uppers by browsing the AR15 Stuff and Thangs section on the site. Whether you're building a predator rifle, a general-purpose DMR, or a lightweight hog-hammer, the Centurion is a killer foundation.