Even though I've had all the parts for about a month or so, I still don't have the new scope on the old Stevens .22.
When I found the Weaver base, I figured I was in like Flynn, because the receiver is already tapped for a Weaver base; in fact, what was on the rifle was a Weaver G4 scope in a Weaver N3 base/ring combo unit. The hole dimensions on the new base are identical to those on the N3. But when I put the new scope on, it's not over the bore, it's off to the right just a little, and it's not parallel to the bore either, pointing a bit to the right.
The receiver on the Stevens is a cylindrical receiver, with the holes drilled at about 45 degrees down on the left side. I can't imagine that Weaver would change the geometry of a scope base which fits such a large number of rifles. The Midway website lists -- I dunno/remember -- over 20 rifles for the base I bought. For example, a friend of mine has a Mossberg with the same dimension receiver.
Here's what I think happened. Whoever drilled/tapped the receiver got the holes wrong. The N3 base is stamped sheet metal, so it could be tweaked over into alignment with the bore. Looking at it, however, I see no evidence of such. I suppose a decent gunsmith could polish out and refinish the base to look good after doing so. But a decent gunsmith wouldn't get the holes in the wrong place either.
Or, I could be wrong, and Weaver really has changed the hole geometry slightly.
Anyways, what I think is happening is that the holes are a little higher on the receiver than they're supposed to be. Since it's a cylindrical receiver, that causes the whole base to rotate around the receiver, which puts the scope to the right of the bore. And if the front hole is just a bit higher than the back hole, the front rotates just a little further, accounting for the out-of-parallel condition. Just eyeballing things, that does appear to be the case (the front hole being higher).
Well, drilling/tapping is $35/hole. The base has 4 holes, so it's a simple matter of just drilling for the other pair. But I'm a bit reluctant to drop another $70 on this project. I purchased the new base and rings from Midway, and they have a very good return policy. I bought the new scope at a gun show, but having an extra scope around is no big deal -- it'll get used eventually on something.
But before I go any further here, I'm wondering how feasible it is to shim the base to get the scope lined up. I have odd pieces of sheet metal, aluminum, and lucite around here, and, worst case, a friend with a machine shop. Seems to me that the worst thing that can happen is it doesn't work. Might wind up with scope pointing upwards to far for elevation to adjust? Seems unlikely. Scratching the receiver and winding up with a spot for moisture to cause rust? I can do final assembly with a little bit of liquid electrical tape -- great stuff, I think.
Update: After messing about with shims, and finding that they left insufficient threads on the screws to secure the base to the receiver, I decided to just use the base/rings as they sit, boresight it, and see what happens.