The Colt LE6943CK Monolithic Upper Assembly feature's Colt's new monolithic upper receiver. In addition to an uninterrupted full-length front rail, this upper receiver allows for a free-floated barrel. This LE6943CK Monolithic Upper Assembly also features a gas-block mounted front flip-up sight with bayonet lug and a flip-up rear sight. The barrel is Colt's standard 11.5" chrome lined M4 barrel with an A2 flash hider up front. Specifications 10.5-Inch 1/7 twist Mil-Spec chrome lined MP tested barrel Unique direct gas operating system eliminates the conventional operating rod and results in fewer and lighter components Accommodates the full range of 5.56mm ammunition, including the NATO M855/SS109 and U.S. M193, utilizing a rifling twist of 1 turn in 7" Straight-line construction disperses recoil straight back to the shoulder, increasing handling capabilities, especially during repeated fire Cartridge case deflector allows easy operation in both right and left handed shooting positions for increased tactical applications Muzzle compensator further reduces muzzle climb and helps eliminate flash and dust signatures Ejection port cover protects the chamber from dust and mud Field strips easily without special tools for simple field user maintenance Flat top receiver allows for removable carrying handle and easy mounting of accessories Target style rear sight features dual apertures (0-200m, 300-600m) and adjusts for both windage and elevation High strength materials for greater comfort and effectiveness Caliber - 5.56mm Gas Direct system, Locking bolt Front Sight - Adjustable front Rear Sight - Target sight adjustable for windage and elevation Flash Hider