So here’s the scoop. While at work I read on the Leupold website that this is somewhat common. And to shim the scope in the ring as a correction. Once I got home I grabbed the Tasco set it back in the rings and it was on zero still for the most part with a ton of upward travel left should I have needed it. Set the leupold in and same trouble as before. It was odd that the ring caps fit fine over the Tasco and one cap doesn’t fit worth a hoot on the Leupold. So I measured them. The tasco is .003 less than an inch and the leupold is .004 more than an inch. The ring sort of snaps into place over the scope. So reading today some more on shimming scope and different material sources I found that my Costco milk jug is about .020” thick. Cut out a shin and it came to zero pretty handily. It still seems odd to me that this would happen and makes me think that I’d never want a Ruger high power if this problem is common. With any other base one could place a shim under a scope base and I would have preferred that.
What seems odd is the Tasco had no problem yet the Leupold had the problems, yet it's the rifles fault? Hmmmm... Things that make you go hmmmm... I've never had an issue with any Ruger integral ring system. I don't use Leupolds anymore either... Hmmmm
It is very likely that BOTH scopes are on the ragged edge of their lower elevation adjustment and the Tasco simply had a bit more left than the Leupold.
And besidies sh*ttly machined factory rings , the older m77/22 Rugers often suffer from "barrel droop" in the reciever due to the V- Block barrel clamp at 6 o'clock ahead of the action. This is pretty common on Ruger 10/22s as well..
Given how short the front reciever ring is on the m77/22 rifles and the often sloppy slip fit of the barrel tendon into the action, it's easy to see how the barrel could be pull downward a few degrees in the front in the acton when tightened.
Unfortunately, there are a LOT of opportunites for "stacking toletances" to rear their ugly heads on the m77/22 rifles ..
and it ain't Leupold's fault.