Sounds like you might have "Conetrol" rings. See
here for other images and assembly/disassembly.
I've also seen and "disassembled" some old, 1-piece scope rings on scopes where you actually remove the objective and ocular bells and slide the rings off the ends. I can't recall the brand of scope, but as you can imagine, they weren't nitrogen or otherwise inert gas purged.
C