Proof Bbl Cf Pr15 338Arc 12 Pistol .750 1-8

The Proof Research .338 ARC barrel for AR-15 pistols brings precision and power to a compact platform. This 12-inch rifle-length profile carbon fiber barrel is engineered for shooters building or upgrading an AR-15 pistol chambered in .338 ARC—a potent intermediate cartridge that delivers rifle-class performance in a short-barrel configuration. Proof Research barrels are known for match-grade accuracy and durability, making this an ideal choice for dedicated AR pistol builders who demand serious capability in a handy package.

Built with a 1-in-8 twist rate, this barrel stabilizes the wide range of bullet weights that .338 ARC handloaders and manufacturers are developing for the cartridge. The pistol-length gas tube keeps the system optimized for the shorter platform while the .750-diameter gas journal provides straightforward compatibility with standard AR-15 pistol components. The 5/8-24 muzzle threads open the door to suppressors, flash hiders, and muzzle devices—practical add-ons for shooters who value both performance and hearing protection.

Proof's carbon fiber construction reduces barrel weight without sacrificing rigidity, a real advantage when you're working within the compact, high-recoil environment of a pistol-frame rifle. Whether you're assembling a dedicated range build, a short-range hunting pistol, or a truck gun, this barrel delivers the precision and reliability Proof is known for at a component level.

Key Features

• Carbon fiber barrel for reduced weight and improved rigidity
• 1-in-8 twist rate optimized for .338 ARC projectiles
• Pistol-length gas system suited to short-barrel platforms
• 5/8-24 muzzle threads for suppressors and muzzle devices
• .750 gas journal for standard AR-15 pistol compatibility
• Match-grade accuracy from a respected precision barrel manufacturer

Specifications

Frequently Asked Questions

Will this barrel fit my AR-15 pistol?

This barrel is designed for AR-15 pistol platforms with a pistol-length gas system. Confirm your receiver and gas tube configuration match before ordering.

What muzzle devices can I use with this barrel?

The 5/8-24 threads accept any suppressor or muzzle device with a 5/8-24 female thread—the standard for most .338 ARC and larger-caliber suppressors and brakes.

Why a 1-in-8 twist rate for .338 ARC?

The 1-in-8 twist is optimized to stabilize the range of bullet weights available in .338 ARC, from lighter varmint rounds to heavier hunting and target projectiles.

Is this barrel assembly complete or a component?

This is a barrel component; you will need a compatible upper receiver, bolt carrier group, charging handle, and other AR-15 pistol components to complete your build.