Take advantage of the next generation evolution in .22 caliber ballistics with a 20 22 ARC. Designed for the AR15 platform 22 ARC is made to take advantage of the heaviest 22 caliber bullets for an exceptional shooting experience. – Caliber .22 ARC – Barrel Length 20 – Barrel Twist 1:7 – Barrel Contour MT – Barrel Material 4140CM Nitride Finish – Barrel Twist 1:7 – Muzzle Thread 1/2 x 28 – Gas Port Location Rifle