I think their failure rate is somewhat dictated by your rifles accuracy and what you expect of them... If you have custom rifles well put together with premium barrels and only achieve 1.5 Moa accuracy with a certain scope mounted it may be causing you some grief.. Change scopes and are then shooting 1/2 moa groups it becomes pretty easy to point a finger.. If, on the other hand, your set up gives you that 1.5 moa accuracy and you're perfectly satisfied go forth and live happily ever after..