The Proof Research Proof Bbl Cf Bolt 7mm BC 20 Sendero Defiance Di delivers precision and reliability in a compact, high-performance barrel system designed for serious long-range hunters and competitors alike. Built by Proof Research, this 20-inch, Sendero-contoured, carbon fiber-wiber bolt-action bolt assembly pairs a tight 8 twist with a 5/8-24 muzzle thread to optimize stability, velocity, and predictable shock along the shot string. Weighing just 2 pounds 10 ounces, this lightweight configuration minimizes felt recoil while preserving rigidity and heat dissipation for sustained accuracy in demanding field conditions. Calibrated for the 7 BC cartridge family, the barrels bore geometry and matched chambering work in harmony with precision handloads or factory ammunition to deliver clean, suppressed-style performance with improved ballistic coefficients, reduced point of impact shift, and consistent shot-to-shot results. The Sendero contour is optimized for bench or field use, offering a balance of stiffness and balance that enhances tracking and zero retention across rapid strings. Ideal for top-tier rifle builds, this barrel system helps shooters achieve tight groups at distance, whether you're engaging distant game or competing in precision matches.