Leupold ringmounts are a high-quality alternative to firearm manufacturer ringmounts or as a no-tap mounting method for most .22 rimfire rifles with an 11mm, 13mm, or 3/8" dovetail rail. This model is designed to fit a Ruger No. 1 & 77/11, and because these rings are machined from solid steel, they offer superior integrity and tighter tolerances.