Premium Grade Parkerized AR-15 Rifle Barrel, 16" Contour M4 Barrel, 1 in 8 twist. Gas port drilled for carbine-length gas system and threaded for a compensator. Barrel extension in rear with M4 feed ramps. Gas port diameter .070 at carbine length. .750 gas block diameter ready to install into receiver. Chambered in 5.56 NATO. Parkerized finish. Made from 4140 cold-rolled steel. Not chrome-lined. Weight approximately 1.90 lbs.