The Colt M4 LE6921EPR Upper Group is a complete upper receiver assembly that includes a 14.5-inch barrel. This upper is designed for use with .223 Rem and 5.56 Nato calibers, providing versatility for various shooting applications.Key FeaturesBarrel Length: Features a 14.5-inch barrel.Caliber: Chambered for .223 Rem and 5.56 Nato cartridges.Rate of Twist: 1-7 twist rate for improved projectile stability.Style: Complete upper group includes bolt carrier group (BCG).Color: Finished in black for a sleek appearance.