I'm getting close on a deal for a lovely older custom rifle with claw mounts. Unfortunately, it presently has an older 26MM scope in need of replacement. Does anyone make a low magnification 26MM scope today? I believe Schmidt & Bender did at one point but I no longer see them offered for sale.

Have you considered getting the older scope serviced and conditioned? There are a few companies that provide that service a pretty reasonable prices.

Does anyone make shims to mount a modern 1" tube scope in 26mm rings? Or is this a different problem?

Brownells makes the inserts to use small scopes in large rings, but I don't think they make a set to use a 1" scope in 26mm rings. The difference is too minute. You could probably use some sort of friction tape.

Yeah, I guess that is pretty small...

By my calculations, shim stock 0.012" thick (0.010 would probably work, maybe even 0.015), wrapped once around the tube (no overlap) inside the ring should do it. As long as the shim is not wider than the ring, you'd never see it, or the gap.

Brass shim stock would probably work best.

Heck, the rings may have that much take up in them anyway. Or if they're split rings, taking off a little material on the mating faces would work too.

I have bought two Kollmorgen 26 mm scopes off of eBay for around $45. Look for the ones with Brooklyn NY on tne ocular lens, they made the Norden bombsite, and sniper scopes during the big war. They are very good scopes, one of mine has a single post reticle, scratches on the outside, the other is PREMO! Both are 4X.

Hungarian made S&B 6x42's certainly used to be a true 26mm tube. I don't know if that is stil the case, or if they are even available in the US.

You might get a result with a post in the Euro forum.