I have used Lyman Supertargetspot scopes for fifty years. They stand up well so far! I have used them on rifles from .22 LR thru 50 BMG.

The Lyman scope operation closed long ago in CT.

I have two of them and interchange them with a Unertl scope on the same bases. Also the Feckers and Lischerts should fit as well.

They are really expensive at gun shows it's true. Must be a good reason for that!

Thanks to Mr. Martins reply I have started to research the beginning of the optics industry. I found a very interesting article titled "The Life & Times of J.W. Fecker" at Snipers Paradise. It seems that the industry was moving at warp speed during the early 1920's. One things I have learned of value is that the industry was advancing due to it's technological discoveries, not marketing campaigns. Most of the key players were astro physicists that had a passion for the shooting sports.
I bet the collector value of these optics is going to go through the roof in the near future.