Our bolt-action barrel blanks allow you to customize your rifle by choosing from a variety of calibers, lengths, contours and twist rates. These barrels are designed to fit a wide range of actions, giving you the flexibility you need for your build. Once received, the barrel will be ready for threading and chambering by your gunsmith. This is perfect for wildcat cartridges that don't follow standard designs. PROOF RESEARCH barrels are carefully engineered to operate safely within SAAMI and CIP pressure limits. If you have any concerns or questions, please contact our customer service team for guidance. Up to 64% lighter compared to traditional steel barrels with a similar contour Enhanced thermal resistance - optimized heat dissipation for cooler and more durable barrels The product exhibits exceptional durability, being encased in high-strength, aerospace-grade carbon fiber that is infused with a proprietary matrix resin Barrel twist rate - 1:8 Shank diameter - 1.20 inches Breech length - 2.5 inches