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 Tikka Rings are able to fit right onto the receiver?s dovetail with no need for a mounting base. The Tikka Fixed Rings utilize 4 T-15 Torx style socket cap screws for secure and permanent optics mounting and also feature a redesigned recoil pin to provide a stronger bearing surface for higher recoiling rifles. Permanently attaches to base. Tikka specific recoil pin for positive engagement of ring to receiver dovetail. Rings securely mount around scope using 4 Torx style T-15 socket cap screws 25 in/lb. of torque recommended.