Specifcations and Features:Caliber: 5.56x45mm NATOTiwst Rate: 1:8 Right HandBarrel Length: 16"Barrel Type: Bull BarrelBarrel Material: 416 Stainless SteelBarrel Features: Free FloatingGas System: CarbineUpper Receiver Type: FlattopUpper Receiver Material: Forged Aircraft 7075 T6 AluminumUpper Receiver Features: "T"-Marks, Brass Deflector, Forward Assist, M4 FeedrampsUpper Receiver Coating: Anodized to Mil-SpecSight / Gas Block: Picatinny Rail Gas BlockMuzzle Device: N/AHandguard: National Match Free Float Carbine HandguardMade in the USAFits: AR-15 lower receivers