What's in the Box Radical Firearms RF-15 Socom 5.56 NATO AR-15 Rifle with 15-Inch RPR Free-Float Rail (1) 30-Round Magazine Cable Lock Owner's Manual The Radical Firearms 16" Socom 5.56 NATO AR rifle uses MIL-STD Upper and lower receivers along with the 15" RPR free float rail system for increased accuracy, keeping your hands cool, and giving you plenty of room for accessories. Regardless if it s your first or fiftieth, a Radical Firearms AR rifle will not disappoint! Firearm Specifications SKU: FR16-5.56SOC-15RPR UPC: 816903022823 MFR#: RF00028 Barrel Length: 16" Barrel Material: 4140 Chrome Moly Vanadium Barrel Finish: Melonite Barrel Profile: Socom Barrel Thread Pitch: 1/2x28 Chamber: 5.56 NATO Twist Rate: 1:7 Barrel Extension: M4 Feed Ramps Gas System: Mid Length Gas Block Type: .750 Low Profile Gas Block Muzzle Device: A2 Flash Hider Upper Receiver Material: Forged 7075 T6 Upper Receiver Style: M4 MIL-STD Upper Receiver Finish: Type III Anodizing Forward Assist: Yes Dust Cover: Yes Handguard Type: Free Float Handguard Style: M-Lok Thin Rail Handguard Length: 15" Charging Handle: MIL-STD Lower Receiver: Forged 7075 T6 Lower Receiver Finish: Type III Anodizing Fire Control Group: MIL-STD STYLE AMBI Buffer Tube: Carbine MIL-STD Stock Adjustment: 6 Postion Stock: B5 Bravo Magazine: 5.56MM 30 Round