PROOF Research PR15 PXT 6mm ARC 16" Carbon Fiber Barrel

6mm ARC in a 16" carbon fiber barrel is a lot of reach out of a standard AR-15. The cartridge pushes long, heavy 6mm bullets fast enough to stay supersonic well past where 5.56 quits, and it does it inside a small frame magazine well. Rifle length gas on a 16" barrel gives a long dwell and a soft push, which is easy on brass and easy to shoot fast.

The core is match grade steel, turned down and wrapped in carbon fiber for stiffness without the front end weight. PXT rifling eases the bullet into the lands with a progressive twist that reduces engraving force, and that matters more in a 6mm than almost anywhere else because throat erosion is what usually ends a 6mm barrel's life.