The Shaw AR-15 barrel in 6mm ARC is an 18-inch stainless HBar-contour barrel with straight flutes, built for a rifle-length gas system (brand part no. AR15HBSSSF186ARC). Shaw Barrels cuts it from 416R stainless steel with a bead blast matte finish and a 1-in-7.5-inch twist, and the straight flutes take weight out of the tube while adding surface area to shed heat. The muzzle is threaded 5/8-24 for a brake, flash hider or suppressor, and the barrel weighs 2.20 pounds. It is a barrel for builders putting together a 6mm ARC AR-15.

Key Specifications

• The cartridge is 6mm ARC (Advanced Rifle Cartridge), a short-action round designed for the AR-15 platform.
• The twist rate is 1-in-7.5 inches, matched to the heavier bullets that 6mm ARC shooters run.
• Barrel length is 18 inches, long enough to take advantage of the cartridge’s velocity.
• The contour is HBar, a heavy profile that stays stiff and holds a zero through longer strings.
• The material and finish are 416R stainless steel with a bead blast matte finish, a combination that resists corrosion and wear.
• The tube has straight flutes, which cut weight and add cooling surface compared with a plain heavy barrel.
• The muzzle is threaded 5/8-24, ready for a brake, flash hider or suppressor.

Frequently Asked Questions

What gas system length does this barrel use? Shaw builds it for a rifle-length gas system with a .750-inch gas block diameter and a dimpled gas journal.

What bolt and feed ramp does it need? Shaw lists a 30 caliber extension feed ramp cut and a 6.5 Grendel Type II bolt and headspace for the ARC. The bolt is not included with the barrel.

Is the muzzle threaded? Yes. The muzzle is threaded 5/8-24, so it accepts the common 5/8×24 muzzle devices.

Buy the Shaw AR-15 Heavy Barrel, 6mm ARC, 18-Inch Stainless, Straight Fluted

A good barrel is the biggest accuracy upgrade you can make to an AR-15, and a stainless HBar tube chambered in 6mm ARC makes a strong foundation for a build. Order it from our Lubbock, Texas gun shop for fast, direct shipping, and see our other rifle barrels while you are here.