Less costly scopes, especially on hard kicking rifles, tend to shoot loose. I'm not going to mention its name because its line of scopes has improved, but I once had a 6x on my 22-250 that I could shoot at least one inch groups consistently. I remounted it on my Model 70 Winchester .375 H & H. After about twenty rounds I was hitting all over the target. I remounted the scope on my 22-250 to check it out: it grouped shotgun patterns.
A suggestion, get rid of your head aches and put a Leoupold or a Burris on your rifle.
Clifford L. Hughes