check out these rifle rings....

toad67

Looks like they are hinged. Never seen anything like it before.

https://www.gunbroker.com/item/844561055

JimmyJack

Id be afraid to use it? What a dandy.

savage170

made by a company called Canis Latrans I have a rifle that came with them never had any problems with them.
http://www.cl-sports.hk/en/ProductShow/index/word/18592.html

charliemeyer007

Very interesting. I like the spirit level in the back ring.