PROOF Research pre-fit carbon fiber & steel barrels are designed to fit the Fuzion, Fuzion Ti, Razor & Razor Ti actions from Lone Peak Arms. Your barrel will arrive chambered/threaded and ready to be installed in a simple operation requiring few specialized tools. Simply torque your barrel on using the proper action wrench and torque setting, double check headspace with proper gauges and head to the range! Our Lone Peak Arms pre-fit barrels are here to deliver extreme accuracy, performance and reliability