Have you checked your rear sight? The problem you’re having is so unlike Ruger. Could the recoil be changing its point of aim?
I would also shoot 3 rounds out of only one chamber at a time and see if you can get any better groups.
“Peace is that brief glorious moment in history when everybody stands around reloading.” – Thomas Jefferson.
Politician's are like diapers.
You need to change them often,,,,, for the same reason!