I have them on 3 rifles from 22-250 to .308 and prefer them over everything else. Originally I came across them because of a bench rifle I had that I could not get enough elevation adjustment out to 500 yds. The inserts took care of that and another nice thing is they will not mar the scope (no more lapping). Take the scope off and looks brand new no dings, dents etc. I have heard from others shooting magnums and they have had no problem either (slippage etc.). Just put a set on a Survivor and used the Mediums with no clearance problems and a Sightron II 3x9x42. :-)