Using a a standard mount, I installed these rings onto a Savage Axis .223 and went to the range to finish sighting in the scope. 25 rounds later, I felt the scope move and upon disassembly founf the key that sits on the rail had sheared off on the front ring and the rear key eas half sheared. It appears that the metal was cast then machined and the casting had a lot of imperfections.
I did not lose a lot of $ in these rings, but I will now need to repeat the sighting process.
Pros: Low cost, ease of use and installation
Cons: Brittle metal, not durable, early failure
This review was written in the old system and had content requirements that are different than reviews written today.