Convert your AR rifle to a compact mil-spec shooter with an upper chambered in 9mm. Its mil-spec certified 4140 chrome-moly vanadium steel 16" barrel is magnetic-particle tested, has a 1:10 twist, sports an 11° recessed target crown and WASP-treated. It has an A2 flash hider with a crush washer and a M4 single heat shield/handguard. The forged M4 upper receiver features a semiautomatic bolt carrier, is T-marked and has M4 feed ramp cuts. It's also head-spaced and test-fired before it is shipped to ensure optimal performance. Mil-spec .250" takedown pivot pin. Standard gas-impingement operation.