Ballistic Advantage Premium Series, DMR Profile Barrel, 6MM ARC, Fits AR10, 20 Threaded Barrel, 5/8x24 Thread Pitch, 1:7 Barrel Twist, Rifle-Length Gas System, Bead Blasted Stainless Steel Finish, Silver BABL6MM003P This 20" 6MM ARC barrel is machined from 416 Stainless Steel with a bead blasted finish. The Premium Series Barrels feature a Nickel Boron Coated Extended M4 Feed Ramp Extension.