That is wierd. A couple of quick ideas which you probably already know about.

First, sometimes when you adjust a scope, it' s fairly common to to " knock" it. You turn the adjustment (clicks), then you rap the scope using your knuckle or a little rubber mallet (I' ve seen guys at the range using things that look like a little doctor' s reflex hammer). This overcomes any sticking in the adjustment. If you don' t, it could happen that moving the adjustment won' t actually move the scope until jarred by the next or subsequent shot. Therefore, that next shot might not actually show the adjustment you tried to make. You therefore adjust again, and the next shot might not show adjustment, or it might show the cumulative adjustments you' ve made because it' s finally moving into place. It can be erratic. This can happen with even the best of scopes, at least as far as I' ve read. I did actually experience it once, so now I kind of just do it habitually. And like I said, I' ve seen guys at the range doing it quite a bit (I just rap it with my knuckles).

Another thing I' ve read about, but not actually experienced. That is when the bottom half of the rings aren' t perfectly aligned - when you tighten down the top half of the rings, it can flex the scope and cause wierd aiming. I haven' t actually experienced this with my Leupold scope w/ burris rings, but I' ve read about it on web sites that talk about mounting new scopes. If this is the case with your rings, it could be that your old scope either settled into this, or was unaffected by it. I believe correcting the ring alignment is called " lapping" and not all that uncommon? Can' t give you a reference, but check for info on mounting new scopes/rings and I believe you' ll find it. Best of luck to you. -zeke