The Colt M4 Upper 5.56 is a complete upper assembly featuring an 11.5-inch barrel, designed for use with AR15 platforms. This upper is chambered for .223 Remington and 5.56 NATO cartridges, providing versatility for various shooting applications.Key FeaturesBarrel Length: Fitted with an 11.5-inch barrel.Caliber: Compatible with .223 Rem/5.56 NATO ammunition.Rate of Twist: Features a 1-in-7 twist rate for optimized bullet stability.Style: Complete upper assembly for easy installation.