The Colt M4 Carbine is a truly iconic AR15 model, is one of the most loved firearms in the industry. These rifles have been put through the ringer by U.S. Military and Law Enforcement professionals alike. There's a reason why they are the featured rifle of our armed forces. They really can withstand anything you throw at them. The barrel is 16" in length & comes with a chrome-lined finish with a 1-to-7 twist. A middle grounds between an AR15 rifle and an AR15 pistol. The receiver is made of 7075-T6 aluminum.