Many people use them and have no problems. Some folks, even folks who have used them on Rimfire Rifles, have had problems with them, throughout the years. Scopes are the Achelies Heel of our game. Often, one never knows if their scope is giving them problem and fight a loosing battle with other supposed issues with their rifle and or ammo, etc, etc.
Last time I looked, there were 4 frozen Leup Comp scopes for sale on the classifieds here. I have one I have used for years and like it very much. They are very easy to adjust. They are as positive a scope setup as one can ever have, in my opinion. I don't use mine on my RF riflr because the action is too short but I have considered having a rail made and buying another frozen setup for my FR rifle.