I have mounted and bore sighted numerous scopes but today ran into a first. I had a Nikon 4.5-14x40 mounted on a Browning A-Bolt 243 wssm that I took off and was going to mount on a Ruger #1 300 win mag. The A-Bolt was a tack driver with this scope and never had a bit of problem with adjustments. Anyway I mounted the scope on the #1 and I do not have enough windage adjustment to center crosshairs when Bore sighting. So I had a Leupold and another Nikon that I went ahead and mounted on the #1 to see if they would work and they both centered just fine when I Bore sighted each. This is driving me nuts. What is the problem.

Have you actually shot a couple rounds through it yet? I would optically center the scope, or if it is already mounted perhaps just screw the windage and elevation all the way in, then all the way out while counting the clicks, and then back in half that number. Test fire it at a target at 50 feet and see if it adjusts to dead center and 3/4" low.

to find center put the scope against a mirror block the reflection of the cross hair with the crosshair and they are centered.