Colt M4 Carbine, 5.56mm cal. semi-auto. Serial #CR032931. Excellent, like new condition. Perhaps test-fired. 16" stepped barrel has a 1/7" twist and excellent bore. Flash-hider. Black tactical finish is 99%. Collapsible stock. Short, round vented forearm. Flat-top with rear fold-down adjustable rear peep sights. High post front sight. One MagPul 30-rd. plastic magazine. Super nice and clean! Every household needs one of these! Gunrunner West item.