Yes, I have a Burris PEPR and a Vortex Scope mounted on my RRA 458 SOCOM. 3 shots and it was zeroed at 30 yards. 3 more shots and it was 2 inches high at 100 yard. I had a scope slip once and since then, after mounting any scope; I take a pencil and mark the scope tube before and after each side of both rings as a quick-check visual indicator of slippage.
What size is your scope tube? 1 inch or 30 MM
What size is your PEPR? 1 Inch or 30 MM?
You can put a 1 inch tube into a 30 mm ring but it will not hold the scope. If you try to put the 30MM inside of a 1 inch ring, you will eventually crush the tube.
Someone out there does make a 30MM to 1 inch reducing insert for rings. I have never tried them but understand they work pretty well. I could see just buying 30MM rings and using the inserts as it would allow your optics to be switched back and forth between 1 inch and 30 MM.
I use the purple lock-tight on my ring screws. This has also helped me.