Mi 11.5inch Upper Receiver Group, Mi-crmhd10.5 M-lok(TM) Handguard, .223 Wylde 1/8 Barrel Forged 7075 T6 Aluminum Upper Hard Coat Anodizing T-Markings on Receiver 11.5 inch Chrome Lined, Phosphate, 4150 CrMoV Threaded 1/2x28 Chambered in .223 Wylde Criterion Core Barrel, 1/8 Barrel M4 Feedramps Carbine Length Direct Impingement Gas System MI-CRMHD10.5 Combat Rail HD Series M-LOK Handguard MI A2 Flash Hider Weight 3.2 lbs MagpulA(R) and M-LOK(TM) are trademarks of Magpul Industries Corp Complete Upper Receiver groups do not come standard with charging handles and bolt carrier groups.