Complete ready to fire upper, with your choice of a 12″ barrel, 16″ light weight barrel, 16″ mid-weight barrel, or 18″ light weight barrel. Includes complete bolt carrier group, charging handle, mid-length GI plastic hand guards, and Tromix muzzle brake. Barrel muzzle is threaded 11/16-24, barrel twist is 1:24, chromoly steel. This upper on a standard M4 style lower will result in a complete rifle weight of 6.1 pounds with the 18″ light weight barrel installed.
Note: With a Tromix 16″ light weight barrel, optional Midwest-Industries 9.25″ hand guard, and optional thread protector, the complete rifle weight on a standard M4 style lower is 5.49 pounds.
********** All complete Tromix .450 Bushmaster uppers are test fired with Steinel Ammunition (www.Steinelammo.com) prior to shipping. **********