DNZ's Freedom Reaper Picatinny Rails will mount to the top of your receiver. These rails are made to 1913 Mil specs. Base screws are 6-48 X 1/4" long and screws use a 7/64" Allen wrench. Model Freedom Reaper Picatinny Rail Style Picatinny Finish Aluminum Pieces 1 Series Picatinny Rail Material 6061-T6 Aluminum Mount Type To Receiver Rings Included No