Many Stealth Upper owners boast of shot groups smaller than MOA. Stealth Uppers are considered by many to be the finest improvement that can be made to a stock AR15 Rifle. Stealth Barrels are available in lengths from 12", 14.5, 16, 18, & 20". Stealth barrels are chambered in .223 wylde, 1-in-8 twist rifling in medium-weight contour.Barrels arrive with a LaRue Precision Barrel Extension installed, Threaded muzzle (1/2x28), precision gas hole, and gas block divots at the 6 oclock position. All barrels are available with either Standard A3 or M4 Feed Ramps.