I can tell of a first hand experience with an IOR 6-24X50mm 35mm illum. MP8 reticle. I field tested one last fall because I had a lot of customers asking about them.
The glass was superb. I had it mounted on a Browning A-bolt in .300 RUM that I built. I took two whitetails with it last fall, one at 660 yards (laser RF), the other at 1006 yards (laser RF). Great so far, then reality set in.
I had put about 75 rounds through it at that point, one morning a coyote crossed my path. When I squeezed the trigger the scope went blurry. Any adjustment to the scope made no difference.
I called Val at IOR and told him what was going on with it. He asked what I had it mounted on and I told him, then he asked if I was using a muzzle brake, which I was. He then proceeded to tell me that muzzle brakes are "scope killers" and that all the other people in the industry he had talked to agreed, then went on to explain that this was a fairly common occurence with the larger IOR tactical scopes. I explained that the Leupold that once held residence on that particular set-up had withstood 100's of rounds and was still in my arsenal as good as ever. Val told me if I liked the Leupold, put it on the scope killer and he would send me a replacement for the IOR, but not to put it back on the same rifle without taking the brake off. Needless to say I received a replacement scope and someone else is the proud new owner.
If that scope could not make it to the 100 round mark on a .300 RUM, what would a .50BMG do to it? I wonder if he would recommend shooting the big 50 without a brake?