Product Description The Proof Research PR15 Carbon Fiber Barrel in 6mm ARC is purpose-built for AR-15 platform shooters who refuse to compromise on weight, accuracy, or durability. Measuring 14.5 inches in length with a 1:7.5 twist rate and 4-groove rifling, this barrel is optimized for the ballistic demands of the 6mm ARC cartridge. A 5/8-24 threaded muzzle offers broad compatibility with popular muzzle devices, while the intermediate gas system and .750-inch gas block journal ensure dependable cycling across a wide range of loads. The barrel&';s aerospace-grade carbon fiber wrap, impregnated with Proof Research&';s proprietary matrix resin, delivers a dramatic reduction in weight compared to traditional steel barrels while simultaneously improving heat dissipation for cooler, longer-lasting performance during even the most demanding shooting sessions. Product Highlights Dramatically Lightweight: Up to 64% lighter than traditional steel barrels of similar contour, reducing overall rifle carry weight without sacrificing rigidity Superior Heat Dissipation: Aerospace-grade carbon fiber wrap pulls heat away from the bore more effectively than steel, extending barrel life and maintaining point-of-impact consistency Premium Carbon Fiber Construction: High-strength carbon fiber impregnated with a proprietary matrix resin provides industry-leading durability and long-term performance Precision 6mm ARC Rifling: 1:7.5 twist rate with 4-groove rifling is dialed in for the 6mm ARC cartridge, delivering consistent accuracy from the range to the backcountry Versatile AR-15 Compatibility: Standard contour profile, .750-inch gas block journal, and intermediate gas system integrate seamlessly into most AR-15 builds and component sets Specs Brand: Proof Research Model: PR15 Caliber: 6mm ARC Barrel Length: 14.5 inches Twist Rate: 1:7.5 Grooves: 4 Thread Pattern: 5/8-24 Barrel Profile: Standard Material: Carbon Fiber Wrapped Gas System Length: Intermediate Gas Block Journal Diameter: .750 inches Platform: AR-15 MPN: 130421 UPC: 843068130421 Disclaimer: We strive to provide accurate and up-to-date product descriptions, specifications, and images; however, errors or omissions may occasionally occur. We are not responsible for any inaccuracies or discrepancies in the content provided. If you notice anything incorrect or unclear, please contact us so we can correct it. When in doubt, we recommend verifying details directly with the product&';s manufacturer.