This barrel, made by LBE Unlimited is 16” in length with a 5.56x45mm chamber. This chamber will allow you to shoot .223 Remington or 5.56x45mm NATO ammunition. The barrel has a 1:7” twist rate, meaning that the bullet will rotate one full revolution for every 7” of barrel travel. This twist rate is optimized for heavier .223/5.56mm bullets. The barrel has an M4 style contour with the M203 cut out. The barrel is drilled for a carbine length gas system. The barrel is machined from 4142-steel and has a phosphate finish. Total weight of the barrel is approximately 17.9 ounces. The muzzle has a standard 1/2×28 thread pitch, allowing you to put on the muzzle device of your choice.