What kind of scope mount is this? (Old and German)

[uspfan]

I'm not very familiar with rifles and especially with their optics. However, I have a 1930s vintage 22lr rifle with what looks to be a single scope mount outside the chamber:





It measures about 10.5mm across on the "inside" of the dovetail.

I'd love to put an authentic vintage old German scope on it from the 30s, but given my unfamiliarity with rifle optics, I'm not sure how to search for such a thing.

I found a couple images of a Beretta rifle that appears to have a similar mount system:

(bottom gun)



Any ideas? It's the only mount like that on the gun (i.e., there aren't two of them on the rifle), so that's why the Beretta's solution seems feasible.

I'd like to get a scope like this one:

http://www.ebay.com/itm/GERMAN-scop...ltDomain_0&hash=item19d1939415#ht_1354wt_1396

but I'd need to find a more suitable mount, I think.

Any ideas? I'm not even sure if it's doable to attach a scope with just one mount, since I haven't found many examples of that apart from that Beretta. There's no chance of me drilling and tapping the gun, as it's quite rare, so I'd like something that won't damage it.

I'd also appreciate suggestions on old German scopes. Hensoldt seems to have been a standard back then, so that's what I've been searching for, but I'm open to other suggestions. Something likely to be found in 1930s Germany, ideally.

 

[Haxby]

My guess is that the rifle is set up for a Stith mount, but that isn't what's on it.

Edited:
I was looking at the bottom picture, and that rifle is machined for a rear mount, also. I don't know what they called that mounting system. A man named Stith used to make very nice rings to fit it.