I purchased these rings for a Leupold scope. Wanting to make sure that they would meet the specs, I called their support #. Good thing I did. The representative said that others had simply "snapped" the top rings over the tube. He recommended that I pry on the outer edges before mounting them. Otherwise, I would have nicked the scope tube pretty bad. No lapping was required, and the installation was a breeze.
Pros: Quality Product
Cons: Installation was tricky
This review was written in the old system and had content requirements that are different than reviews written today.