DESCRIPTION The barrel is one of the few components that directly affect the accuracy and weight of your build. Designed for corrosion resistance, this barrel will not let you down. This barrel is machined from 4150 Chrome Moly Steel, heat treated to RC 28-32 hardness, and properly stress relieved. This barrel has a nitride finish for increased strength and durability. It is chambered 9mm chamber, with a 1:10 twist rate. This is the perfect barrel for an AR9 build, keeping weight to an absolute minimum, while still offering a significant ballistic advantage. Weight 3.05 lbs Platform AR-15 Caliber 9mm Barrel Material 4150 Chrome Moly Steel Barrel Coating Nitride Barrel Length 7" Thread Pattern 1/2 x 36