Sold as pictured these are NIB complete replacement uppers for departments or owners of existing registered NFA Machine guns or Short Barreled Rifles. These are swap out replacement uppers for the M16, AR-15, M4 rifles. Information and Specifications: Barrel: • 11.5" Heavy contour, Fluted to reduce weight and Heat • 4150 Mil-B-1159F Vanadium Alloy (machine gun rated) • Chrome Lined, and Manganese phosphate • right-handed 1x7 twist (16" 1:8 twist), button rifled (Rock Creek Barrel Blank) • Vortec, A2, or Krink Flash hiders (Optional) •Chamber: 5.56 mm Nato (.223 Cal.) Method of Operation: • Gas Piston operated, rotating bolt (short stroke system) • Reversible piston / gas trap design (two modes of fire) • C.R.O.S. (Corrosion Resistant Operating System): (Chrome plated: Barrel, Gas Block/Tube, Gas Plug, Gas Piston, Bolt Carrier Assembly) Bolt & Carrier: • Chrome plated 8620 steel bolt carrier, heat treated / plated per Mil Spec. • Chrome plated steel bolt, heat treated, to Mil-spec Sights: • Fixed removable A2 front site assemble • Troy flip up rear site (optional) Weight: • Empty – 6 3/8 to 7 1/2 Lbs Upper Receiver: • A3 Flattop, Forged 7075-T6 aircraft aluminum alloy • Hard coat anodized per Mil Spec and Teflon coated black • P4 feed ramp cuts in receiver Price $950 with full auto bolt group. Departments call for quantity pricing 413-698-2345. All NFA rules apply.