Proof Research 130384 AR-Style Barrel 6mm Arc 20" Rifle +1 Length Gas System 1:7.50" Twist 4 Grooves, 5/8"-24 tpi, Stainless Stainless

An optimum combination of high tensile strength along with requisite toughness to withstand extreme chamber pressures encountered during firing. Excellent erosion wear characteristics and corrosion resistance.