The Vortex Precision Extended Cantilever 30mm mount provides the user with the proper head placement and eye relief. They come in several sizes and have options for 20 MOA cant. These ring mounts will position the center of the riflescope tube 1.574 inches (40mm) from the base. For typical safe installation, tighten base screw torque to 45-50 in-lbs and cap screw torque to 15-18 in-lbs.