Thread: shimming scope rings confusion

Yes, you shim the front mount. You work out how much you need to shim with a bit of trigonometry.

h = d x tangent(MOA/60)

Where:
Your calculator is set in degrees
h = the thickness of the shim you need
d = the distance between your scope mounts
MOA = the number of MOA you want to shift the point of impact

If you want the shim thickness in inchs then measure the distance between your scope mounts in inchs. Works for any units including mm.