Description Upgrade your AR-15 with the Proof Research PR15 Steel Barrel in 6mm ARC, featuring an 18″ length and a 1-in-7.5 twist rate. This high-performance barrel is designed for exceptional accuracy and durability, making it an ideal choice for precision shooting. Crafted by Proof Research, a leader in advanced barrel technology, this AR-style barrel is perfect for enhancing your shooting experience. Whether you’re at the range or in the field, trust the PR15 to deliver reliable performance.