The Colt Expanse M4 is a semi-automatic rifle chambered in 223 Rem5.56 NATO. A 16.1 barrel is accompanied by a collapsible stock making the Expanse M4 much easier to transport. It includes a flip-up dual aperture rear sight and a picatinny rail allows for the attachment of additional optics. Details Colt Mfg CE2000 Expanse M4 Carbine SA 5.56 NATO 16.1 301 Synthetic Black Stk Black BLACK HARDCOAT ANODIZED FINISH