DealBrand New American Tactical AR-15 FIX Retro-Fit Gas Piston System 16" Carbine Length Piston .750 Barrel Diameter (Standard M4) Use Your Own Bolt Carrier! 7" is the Distance Between the Front of the Upper Receiver and the Shoulder Where the Gas Block Sits MFG by Adam Arms from CDNN Sports (Product ATI00256) |