What is standard Height Over Bore?

[Lucky]

I believe this is measured to the center of the optic on top of the rifle, from the center of the bore, right?

What is the way to find this on a bolt-action? Do you measure from the firing pin to the top of the scope ring, and then subtract half the diameters of the ring and bore?

Or is there a standard height associated with each type of rings, High Medium and Low? Because I've got a Mossberg ATR with the weaver mounts on the receiver, and high 1" burris rings. If there's a standard HOB for each type of rings on bolt-actions that would be a real time-saver.

 

[ArmedBear]

"Standard" is 1.5", but that's just a "standard" value for ballistics charts, nothing else. Essentially no scope is exactly 1.5" over the bore.

What you use should be determined by gun fit.

Shotgunners usually care a lot more about gun fit, but rifle shooters would do well to pay more attention to fit. Perceived recoil, fatigue, "pointability", and practical accuracy are all greatly influenced by gun fit.

Mount the scope so a good cheek weld leaves your head and face in the right spot so your eye is comfortably lined up with the scope.

This varies with the person, the rifle, the scope and the stock design.

 

[Jim Watson]

There is no magic number. A 6" rule and some eyeball alignment of rings and bolt or barrel will get you close enough to get into the ballistic charts.