Proof Research 6Mm Arc 1-7.5 Twist 14.5'' S/S Barrel

The Proof Research 6mm ARC 1-7.5 twist 14.5" stainless steel barrel brings match-grade precision to modern intermediate cartridge builds. If you're assembling a compact tactical rifle, short-range hunting upper, or precision AR platform build, this barrel offers the bore quality and dimensional consistency that Proof Research has built a reputation on—without the carbon fiber premium. The 1-7.5 twist rate is optimized for 6mm ARC projectiles, ensuring stable bullet flight across the full spectrum of factory and handloaded ammunition in that caliber.

Proof Research manufactures these steel barrels using the same drilling, rifling, and lapping processes they apply to their carbon fiber barrels, which means no compromise in bore finish or concentricity. The barrel is machined from double stress-relieved 416R stainless steel—a pre-hardened chromium stainless specifically engineered for firearms manufacturing to deliver the consistency and durability modern shooters expect. That meticulous process, combined with the properties of 416R, translates to minimal runout and shot-to-shot repeatability, whether you're running it at a 100-yard zero or pushing accuracy at distance.

At 14.5 inches, this barrel strikes a practical balance for modern rifle platforms: short enough for maneuverability and quick handling, long enough to wring useful velocity from the 6mm ARC cartridge. The stainless steel construction resists corrosion better than chrome-moly, a real advantage if you're building a rifle that'll see outdoor use, hunting trips, or storage in variable conditions. This is a bare barrel—you'll need to fit it to your upper receiver and handle headspacing and timing per your build specifications or gunsmith's requirements.