Truglo's Magnum Gobble-Dot Xtreme easily snaps over rib without need for screws. Endorsed by the National Wild Turkey Federation. *Note- Designed ONLY to be installed on a shotgun barrel with a ventilated or solid rib design. Fits- Mossberg 500, 835, 9200 shotguns; Remington Sp-10; Weatherby Orion and Winchester 1200, 1300, 1400, Super X2 shotguns.