Proof Research PR15 PXT 6mm ARC 20" 1:7.5 Stainless AR-15 Barrel

A 20 inch stainless AR-15 barrel from Proof Research in 6mm ARC, cut with PXT rifling. PXT is the company's progressive twist geometry: instead of holding one lead angle the whole way, the rifling eases the bullet into the bore, which cuts engraving force and slows throat erosion. Proof puts the barrel life gain from it at 30 to 100 percent over conventional rifling.

6mm ARC exists to give the small frame AR a cartridge that reaches, without moving up to a larger receiver or a heavier rifle. Twenty inches is where it gives up the least velocity while still handling like a gas gun should. This is the steel version rather than the carbon wrapped one, so it carries its weight out front, which plenty of shooters want for the way a rifle tracks off a bipod. The PR15 designation is the AR pattern side of the Proof catalog.