Barrel: 18" 416R Stainless Steel barrel, chambered in .223 Wylde, with a 1:7 twist, M4 barrel extension, and a Rifle length gas system. The barrel is finished with a .750" diameter low-profile gas block,PSA 15" Lightweight Hex Full Picatinny M-Lok free-float rail and an A2 flash hider.Upper: Forged 7075-T6 A3 AR upper is hard coat anodized black for durability. Featuring M4 feed ramp cuts, these upper receivers are made for us right here in the USA.Bolt Carrier Group: For AR15 and M16 rifles and carbines. The bolt is made of shot-peened, Mil-spec Carpenter 158A(R) steel. The gas key is secured with grade 8 fasteners and staked to the 8620 Steel Carrier. Includes Charging Handle.Lower Build Kit: PSA MOE EPT Lower Build Kit, BlackIncludes: Magpul MBUS Sight Set, Black