Complete Upper Kit includes our custom built barreled upper assembly, bolt carrier group and charging handle, lower parts kit and stock kit. Calibers include 223/5.56, 300 Blackout, 224 Valkyrie, 6.5 Grendel, 7.62x39, 350 Legend, 6.8 SPC II, 458 Socom, 450 Bushmaster, 50 Beowulf, 9MM, 45 ACP, 40 S&W and etc.