How to select the correct Tier One scope mount

Mount Height

• Determining the right height
  • First rule of thumb: All Tier One scope mounts in Medium height are designed to work with a 56mm objective on a hunting rifle. If you have an AR platform rifle, or no barrel taper, or a full length picatinny rail and you have a 56mm objective then you might need the High version. Check using the following method.
  • Measure the scope objective's outer diameter (if the manufacturer states 56mm, it's probably a couple of mm larger for the whole housing)
  • Calculate the theoretical minimum height (this is calculated by halving the outer diameter e.g. Outer diameter is 60mm, theoretical minimum height is half of that, 30mm.)
  • Adjust for the actual, practical minimum height by considering personal preferences, lens caps, and tilted mounts (20MOA/6MIL) and any other forend mounted accessories. 

Key Takeaway: Ensure adequate clearance for the scope to avoid contact with the rail or rifle, while also accounting for lens caps and sunshades. 

Cant (Tilt) Requirements - MOA/MIL

• Incorporating longitudinal cant in your setup for long-range shooting is important. Here are some guidelines:
  • We recommend stick to the minimum needed cant to maintain sight picture quality
  • The typical optimal cant across your rail and mount is going to be: 6 MIL (20 MOA)
  • If you are shooting very long range you may add additional cant with a canted picatinny rail (also called a scope base, action rail etc.)

Key Takeaway: Choose a mount with a tilt that provides enough adjustment range for long-range shooting without negatively impacting image quality.

Adjustment Range Optimization

• Selecting appropriate cant for optimal adjustment range
  • Choose a cant equal to half the scope's elevation range
  • Example: Nightforce ATACR 5-25x56 F1 scope (30 MIL/104 MOA max elevation) should have no more than 15MIL (52 MOA) tilt across the mount and rail. With a Tier One 6MIL rail, and a Tier One Monomount 6MIL, you can achieve 12MIL overall. 

Key Takeaway: To maximize the available adjustment range for long-range shooting, select a mount with a tilt equal to half your scope's elevation adjustment. It is not advisable to exceed half. 

Example:

• 6.5 Creedmoor rifle used up to 1000 meters
  • Recommended total cant (this is total, across your rail/scopebase and mount: 6 MIL/20 MOA)
  • Reason: This provides sufficient elevation for the intended use, and because you haven't added too much cant it reduces optical defects at closer ranges

Key Takeaway: Choose a cant suitable for your rifle's caliber and intended use to balance long-range shooting capabilities and image quality at closer ranges. 

Zeroing Limitations

• Over-tilting consequences
  • Using a setup with cant more than half the scope's elevation adjustment makes zeroing at 100 meters impossible

Key Takeaway: Avoid using excessive cant to ensure the ability to zero your rifle at standard 100-meter distances.