Scope height over bore
How far the scope's center sits above the barrel's center. It decides your cheek weld and the bullet's path at close range. We calculate only the part above the rail, where makers publish it.
What it means
Scope height over bore is the distance from the center of the barrel up to the center of the scope. It has two parts: the rifle’s rail above the bore, and the mount’s height above the rail.
What it changes in the field
- Cheek weld. A tall mount on a straight stock can leave your cheek off the stock. Ballistic apps ask for scope height because it changes where the bullet hits close in.
- Close shots. The higher the scope, the farther below the crosshair the bullet strikes at very short range.
What to look for
- Where the maker measures. Mount makers do not agree: some give the ring center above the rail, some the bottom of the ring, some a figure with no reference. Two “1.5 in” mounts can sit at different heights.
- Your rifle’s part. The rail-to-bore height depends on the rifle and its base; measure it yourself.
How we use it on this site
On optic and mount pages we show “Tube center above the rail (calculated)” only when the mount maker says where its height is measured from and the optic maker states its tube diameter. It is the center of the tube, not a thermal’s lens axis, which no maker publishes. We leave the rail-to-bore part to you.