Colt M4CQB AR-15 Barrel 5.56x45mm NATO 10.3" Government Contour 1:7" Twist Parkerized with Front Sight Base

The Colt AR-15 Barrel features a true 5.56x45mm NATO Chamber for use with both commercial and military surplus ammunition, while the 1 in 7" Twist Rifling is capable of stabilizing light to medium weight projectiles of up to about 77 grains. The included front sight base is designed for a rear sight mounted to a flattop upper receiver. In 1963 the AR-15 and M16 5.56mm automatic rifles "made Colt the small-arms sensation of modern warfare". Their unmatched accuracy, performance and durability are