GC_UPC Adams Arms AR-15 P1 Gas Piston Upper Receiver Assembly 5.56x45mm NATO 16'' Barrel - 663928 $524.99 FGAA-01359 show more like this 14.25 MidwayUSA GC_UPC Adams Arms P1 MOE AR-Platform 5.56x45mm NATO,16, Black Nitride Steel, FGAA01359 $575.00 FGAA01359 show more like this Free Shipping on most orders over $49 Optics Planet