- A. Enter the actual outside diameter (in millimeters) of the Objective end of your scope, remembering to include scope covers if you use them.
- B. Enter the size of your scope tube in millimeters. Use 25.4 for 1 inch scopes, or 30mm, 34mm or 35mm.
- C. Enter height (in millimeters) of any adapter rail (if you are using one). Use the tool on line "F" below, to convert from inches if you need to.
- D. Place a straight edge across the receiver and measure the distance from this level down to the barrel. Enter that number here.
- E. This is the minimum height of the rings that you will need for the scope to clear the barrel.
- If you are using 20 MOA rails, higher rings may be required.
- This Tool makes no provisions for Bolt Handle clearance.