Heavy Match 1x9 twist barrel attached to Mil-spec upper, and CAR length hand guards. The CAR kit comes with your choice of A-2 or standard flat-top upper, lower parts kit, Bolt, bolt carrier, charging handle, and your choice of A-2 Buttstock or CAR stock (pictured). Available with HBAR or Light Weight contour barrel.

This AR-15 Rifle kit is headspaced, and ready to mount to your lower receiver.  Once you have an assembled lower with the parts provided in the kit, and mount the upper,  this is an operational firearm 5.56mm.

5.56mm NATO chamber information here.  All barrels made for Mil-Spec 5.56mm NATO