Steel Flash Hider installs with a roll pin (included) in place of the factory front sight. For use on rifles with a barrel diameter of .625, make sure to measure the barrel before you order, some of the early 580 series rifles have the smaller .562 barrel. The compensator is attached to the gun barrel by a 1/8 inch spring steel roll pin. Drilling new role pin hole is required. Gunsmith installation recommended to drill hole for roll pin.