Leupold Standard steel bases are designed specifically to withstand the toughest recoil. The 2-piece bases give you maximum accessibility to the magazine or breech of your rifle and more flexibility in mounting scopes to bolt action rifles. 2-piece bases will fit right or left handed short and long actions. Bases accept any Standard-style rings. Technical Information: Base Type: Standard Material: Steel Fits: Ruger American Rimfire Rifles Mounting Hardware Included