So a few years ago I bought a used zytel stocked 77/22 magnum. It came with a set of Ruger rings and a tasco pronghorn riflescope. I had shot it a few times and the tasco was zeroed. I decided that I wanted a leupold rimfire scope and bought one and mounted it. I can’t get near enough elevation to get to center. I’ve read some on a google search that this in known to be a problem with Ruger receivers being off some. I really didn’t like that information and proceeded to experiment. The rings do not fit all that well. One of the top rings has to be pushed down to sort of snap onto the scope tube. Doesn’t leave me with a warm fuzzy. So I swapped the rings front to back and the problem stayed. And for [bleep] and giggles I measured them with a caliper and they are within .004 “ of each other. Some had said to make sure they didn’t have high power rings. It bothers me the most because the tasco that I loathed so much had enough adjustment to zero but my leupold does not. I’m wondering if I could lap these rings and straighten them out but not sure it will make a difference because won’t the rings be aligned with each other and still not aligned with the bore? Also I read something briefly about the barrel might not be aligned correctly, can anyone shed some light on that? Thanks for reading.

Have you tried other rings? Burris makes a ring set for Ruger rifles.

Seems to me if it was fine with the Tasco, and the problem showed up when switched to Leupold, I'd try a third scope of know quality. If you don't have one, at least put the Tasco back on and see if it will zero again.

I haven’t tried another scope. I could probably do a bit of research and see how much each scope has for adjustment and compare. I’ll put the tasco back on tonight and report back.

The Leupold ones are nice too. Think I still have a set of low blued ones. Warnes are also solid.

BTW, is it possible you mixed up the ring caps or reversed them? Probably not the reason for the POI problem, but maybe the issue with fitting over the scope tube.

It is possible, but the one ring cap fits tighter than the other. I wouldn’t be opposed to buying a different set of rings. But would like to rule out an issue with the receiver first.

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.

It’s not a problem with any of my Ruger’s, both rimfire and centerfire. It seems to me to be more of a scope issue. However that aside, there are options out there. weigan makes a one piece base that uses the factory ring locations.
https://www.jackweigand.com/ also, but harder to find anymore, Burris made signature rings for the Ruger that used the off set inserts but they are impossible to find.

Years ago it was common for guys to shim scopes in the rings, hence Burris creating scope rings with that capability. A friend of mine would shim with different thicknesses of aluminum. Guys doing this wanted to have the rings as close to center as possible with the rifle zeroed from my experience.

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.

What jk16 said. Different scopes have different amounts of internal adjustment. I ran into a similar problem with a Ruger #1. For years it ran a K12 Weaver with no issues, but when I put a different brand scope on it I ran out of windage adjustment. Seems the new scope had very little adjustment. Had to go with windage adjustable rings.