Sounds like the same thing my Ruger M77 30-06 does. The problem with mine is that when the barrel gets hot it goes off center. I'm good for 2-3 shots, then have to wait for the barrel to cool down. It doesn't bother me for hunting, just want one shot and a follow up if I need one. Try letting the barrel cool down for a while and see if it goes back to center, and don't adjust the scope while the barrels hot.