Thank you - to everyone!
The post by Ron AKA got me thinking. I measured the front & rear rings & bases and found them different. Then I checked for any kind of ID marks on them and called the company to confirm.
They aren�t even the correct rings & bases for his receiver!!!
Yup, he bought the rifle used for what he thought was a good price, and was never able to get it to shoot right.
Now we know why!
I�ve got a new (correct) set of rings & bases ordered and will proceed.
I�ll center the scope ahead of time by bringing the windage & elevation adjustments back to the middle of their course, then mount the bases, set the rings and bore sight it.
I�ll also keep my fingers crossed that the shooting goes smoothly. Darn thing is a .300 Win., and I don�t want to loosen my teeth shooting too much.
Thanks for all your help.