Never had this problem before, but twice recently.
Ruger rings on a Ranch Rifle....rings tightened down nicely and evenly....seem plenty tight--scope moved back in rings after about 40 rounds.
Then......Ruger rings on 77/357......same deal.
Is it me? Is it the Ruger rings? I roughed up the inside of the rings on the 77/357 a little and applied a couple of drops of loc-tite to each.
It still moved a little and then seemed to hold. Need more testing to be sure.
Ideas? Is this common? I never had it happen before.