OK, here is the update: it is still happening. Scope is good, rings are good. This is crazy, because I got this thing shooting great, and then the groups went horizontal at 100. Like an inch horizontal with the shots lined up in a row. Then it all went right again. AT 400 yards it really starts to show the pattern to the right. BUT - I can dial in the correction and everything is on target. The scope will make windage and elevation adjustments fine, so what am I doing wrong here? One of the things I noticed is that since I have lost some weight my heartbeat is really starting to show up when I sight in on the target. That might explain the horizonal, but where is the consistency to to right coming from? I am currently fighting the desire to go back to 100 and re-sight the rifle - seems like I am getting into a loop of constantly tweaking if I go down that path. Horizontal zero seems to be good at 100, but not the farther out I go. I realize that this is probably a newbie thing and something basic, but I cant get it figured out. Thanks for any help you may have.