Made to mil-spec standards, this AR15 Model 3H Upper Half from Stag Arms is second to none in quality. Semi-auto direct impingement action. Chambered for 5.56 NATO and .223 ammo. A2 flash hider muzzle device. 16" steel, chrome-lined, manganese-coated barrel. Forged and mil-spec with type 3 hard coat anodizing and a Picatinny rail on top.