The 20″ 5.56 NATO Heavy barrel assembly is the perfect barrel to start your next build and add to your AM-15 collection. This barrel is made from 4150 Chrome Moly Vanadium Steel with a Parkerized finish. Featuring a rifle length gas system with a .750″ gas port and a 1:9 twist. This barrel comes assembled with an A2 Barrel Nut, Triangle Hand Guard Cap, A2 Front Sight Base with Post & Detents, Pinned & Drilled with a Front Swing Swivel. This barrel provides top accuracy and precision for your 5.56 build.