Noveske's Stainless Steel AR-15 Match Barrels feature their exclusive 5.56 Match Mod 0 Chamber, designed to offer outstanding accuracy with both 5.56x45mm NATO and 223 Remington ammunition. Composed of 416R stainless steel that's hardened to 30 RC, the bore is given improved polygonal rifling that slightly boosts projectile velocity and reduces the speed of the bore's erosion, meaning superior accuracy retention that outlasts that of barrels with conventional rifling. This barrel includes the patented SwitchBlock adjustable gas block. The Switchblock has three positions: Unsuppressed, Suppressed, and Off. The block's suppressed setting greatly reduces the amount of excess gas, carbon and fouling produced when a silencer is installed at the muzzle, as well as significantly improving reliability. Gas flow adjustments are made by simply depressing the locking plunger and rotating the selector drum to the desired position. All Noveske match barrels have a medium contour, bead-blasted s...