After you’ve decided on a high-quality scope mount brand, one of the first questions you’ll need to make is, “How high would I need the scope mount to be?” As a general rule, it is better to keep the objective lens of your scope as near to the barrel as possible, hence low or medium-height scope mounts are preferred.
The benefit of this is that the flight of your bullet or projectile will be near to the scope’s crosshairs, reducing hold under / holdover. However, your eye line may occasionally be above the centerline of the scope, in which case you will need to utilize higher sight mounts to bring the centerline of your rifle sight in line with your eyesight.
A mount that is 0.98′′ or 24.90mm to the scope’s centerline is required for a 50mm scope (25.4 mm per inch). The low mount gives you 0.94′′ and the middle mount gives you 1.06′′.
This is due to the fact that the Weaver / Picatinny sight mounts/scope rings are mounted on a Picatinny or Weaver rail. This raises the scope ring’s height, allowing a medium-height scope mount to be utilized when installing a riflescope with a 50mm focal plane. When a 56mm focal is used, a high scope is the best option.
To choose the proper height ring, determine the height of half of the riflescope’s widest point (usually the objective bell of the scope), then know the height first from the bottom of the ring mount to the center of the ring mount, and choose the ring mount height that is slightly over half of your riflescope’s width.