The radical firearms 16" socom 5.56mm ar rifle uses mil-std upper and lower receivers along with our 15" rpr free float rail system for increased accuracy, keeping your hands cool, and giving you plenty of room for accessories.The b5 grip and b5 stock provide a comfortable hold on the rifle whether prone or upright.Regardless if its your first or fiftieth, a radical firearms ar rifle will not disappoint!Action: Semi-AutoCaliber: 5.56x45mm NATOBarrel Length: 16"Capacity: 30+1Trigger: Mil-SpecStock Description: 6 Position B5 Bravo AdjustableMuzzle: A2 Flash HiderReceiver Material: 7075-T6 AluminumSights: Optic ReadyBarrel Description: Chrome Moly VanadiumTwist: 1:7"Barrel Length Range: 16" to 16.99"Hand: RightStock Finish Group: BlackMetal Finish Group: Blued/Black