Proof Research PXT Barrel 6mm ARC Carbon Fiber Rifle Barrel - 18in - PROOF Research PXT AR barrels represent a new evolution in barrel technology, combining advanced rifling geometry with the performance and precision shooters have come to expect from PROOF. PXT - PROOF Exponential Twist - is a complete rethinking of conventional rifling design and twist progression, engineered to reduce engraving force, minimize throat erosion, and create a smoother transition as the projectile engages the rifling. By dramatically reducing rifling lead angle and smoothing projectile engagement into the bore, PXT technology helps reduce wear, improve consistency, and create less felt torque during firing for improved recoil control and the ability to stay on target more effectively. In controlled testing, PXT barrels have demonstrated significant increases in barrel life while maintaining the accuracy standards expected from a PROOF barrel. Our PXT AR barrels arrive fully chambered and ready for installation, making them an easy upgrade for shooters looking to build or refine a high-performance rifle system. Available in both PROOF carbon fiber and traditional steel configurations, PXT AR barrels deliver lightweight handling, precision performance, and next-generation barrel technology across a wide range of modern gas gun applications NOTE TO CONSUMER - THIS BARREL REQUIRES A RIFLE + 1 GAS TUBE Gas Port Size - .750; Gas Tube Length - Rifle + 1;