Scope adjustment malfunction?

PA Shootist

What may have happened to a rifle scope that has the following apparent malfunction? Elevation adjustments have the approximate effect, but also cause a windage adjustment; also, a windage adjustment moves the group the approximate desired amount but also causes an elevation change. It is a Leupold Vari-X II scope, 2x7 variable; mounts are tight and double-checked for no movement; the scope is installed with the crosshairs level, that is there is no cant; there was no change of magnification; the error seems to be consistent, every change on one axis brought the undesirable additional change. The scope is installed on a .338 Winchester Magnum caliber Weatherby Mark V Sporter. I believe I have every reason to think the problem is within the scope, rather than the shooter (me, from a very solid sand-bagged rest) or the rifle itself.

perry shooter

It sounds like you have done a good job of trouble shooting and have eliminated. some of the most common causes so I agree with you most likely the scope . I would send back to Leupold.

Edit because most modern scopes are filled with Nitrogen to prevent fogging . I never try to take them apart to repair. I have one older weaver that the Physical size is perfect for the gun it is on Valmet 412. The only problem comes when trying to change the zero . you move the turret and it takes 2 or 3 shots to move the impact point but once it moves it will stay in zero until I change weight of bullet again. and need to rezero.

PA Shootist

I was hoping that an expert in rifle scopes could explain what the failure mode might be of the adjustment mechanism. I did illustrate the lengths I went to to possibly eliminate the other factors possible in mounting, shooter, etc. I will of course be mounting another scope, and sending this one back for repairs. I just couldn't imagine what would cause one adjustment (e.g. elevation) to drag another (windage) along with it in the different axis. I wondered if the relatively heavy recoil may have broken something internally, or loosened it? The rifle has never been droppped or bumped that I know of; I've owned it since new, for about 14 years. But I haven't hunted with it, never had the need for that powerful a rifle back here in Pennsylvania. I did go to Arizona this year to hunt elk, thought it would be perfect for that, but ended up taking another rifle as this apparent problem had popped up and I didn't trust the scope to remain sighted in.