A few weeks ago I picked up a cheap scope for an old 22 auto that needed one, I just grabbed it as I walked by and purchased it. When I got home I realized it was a scope for a springer,fixed 4 power. Last night I finally got the rifle back from the smith who made a new firing pin for it, anyway when I was mounting the scope I found that it had a hex screw centered in the bottom of one of the bases, that would tighten down onto the receiver to help lock the scope in place.
I'm 63 and I went through alot of scopes in my lifetime, and this is the first time that I've ever seen this done to a scope ring, and it would be an easy thing for anyone to accomplish to help stop a scope from sliding back under recoil that anyone having trouble finding a stop can accomplish. I machined my set of stops 30 years ago when I worked in a machine shop, while being chided by my co-workers for playing with toy guns, LOL, it was a Diana model 35 that I bought in the service in Germany. It came home with me along with a Ruger revolver, with the chamber open and tied in place with a string in my luggage, Times change don't they!.........................steg