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.

Features:
Ruger specific recoil pin for positive engagement of ring to receiver dovetail
Uses 4 Torx style T-15 socket cap screws" 25 in/lb. of torque.