Since each firearm manufacturer has their own proprietary mounting rail design” each ring model must be machined to exacting tolerances for proper fit and function. Because of this” the Warne Ruger Rings are able to fit right onto the receiver’s dovetail with no need for a mounting base.
Warne Scope Mounts Permanent Attached Fixed Ring Set, Fits Ruger M77, 30mm High, Matte Finish 15R7M
