I just went to a school and had a problem with my Leupold 6.5x20. The scope is a older Mark 4. Once zeroed at 100 yards its is dead on. Then move back to 200 and it shoots about a inch right. Then move back to 350 and then close to four inches right. Group size was still half MOA. My buddy that went with me had the same problems. My buddy used 1 MOA left windage to fix the problem. However there was no wind on the range, we measured. First I know it was not a shooting error. Instructors even watched to see if I was jerking trigger, milking the grip, etc. I even dry fire in between shots. The instructors stated that they have had the same problem with the scopes. They stated that if you adjusted the parralax at different ranges it would happen. I did adjust it before shooting and everything was clear, and no shadowing. Then shot four inches right. I then went back to the 100 yard line and adjusted parralax, since it was my zero range. Then I returned to 350 and I was now only two to three inches right, but picture was blurry. The scope has the newer side focus. Anyone else had these problems? The guys that taught the course stated that they had the same problems. Any solutions? Issued rifle so buying a new rifle is not a solution at this point. Thanks