This M&P15 features a 16-inch barrel with chrome lined bore, chamber, bolt
carrier, and gas key. The rifling twist is 1:9. The flash suppressor is the
A2 military style. The upper and lower receivers are fabricated from 7075
T6 aluminum, manufactured in the U.S. by an independent contractor to Smith
& Wesson's specifications. The machining, assembly, and final fit matching
of the parts are done by hand in S&W's plant.