The ultimate long-range AR-15 upper is finally here! The 224 Valkyrie round was developed to bring unheard of accuracy and long-range ballistic performance to the AR-15 platform. Barrel: The Gen2 PSA 224 Valkyrie upper receiver was created with a 416R Stainless Steel barrel with a 1/6.5" twist rate for optimal accuracy over long distances. Cycling reliability is achieved with a rifle length gas system, which is completed with a PSA Low-profile adjustable Gas Block. The barrel is finished off with an A2 flash hider and a PSA 15" Hex Full Picatinny M-Lok Free Float Rail. Upper Receiver: The forged 7075-T6 A3 AR upper is machined to MIL-SPECS and hard coat anodized. These uppers are made for us right here in the USA by a mil-spec manufacturer. Bolt Carrier Group: ToolCraft AR-15 .224 Valkyrie BCG made for Palmetto State Armory OEM use. Functions with all PSA .224 Valkyrie Uppers. 9310 steel bolt assembly, nitride treated for durability. 8620 carrier, nitride treated, with a nitride treated gas key properly staked with grade 8 fasteners. **The 224 Valkyrie upper is designed to function with any Mil-Spec AR-15 Lower Receiver and is to be used with a standard 6.8 SPC Magazine.