same issue with a PSE I bought on e-bay, I tourqed the nuts down so tight on the sight becasue it shifted a few times, but also someone told me that your string will streach and cause this ??? I wonder on that theory, I cannot seem to get that bow to shoot consistant, and I have 2 others that are dead on every time so I am confused also. but if you do get an answer to that problem please let me know. check your sight nuts to make sure they are really tight though, my forst bow they weren't tight enough becasue I was afraid to strip the holes so if It got bumped or bounced in the car I would have to resite it in. hope that helps a bit