OK, I'll ask the question. For that amount of money, shouldn't it hold up longer that two boxes?
I don't think they are made for the inconsistent pressure they exert. When I told him what I was shooting, he said that explains it. Remington had to make some improvements and re-designs on there Versa Max to handle them as well. The ammo was making parts guns out many autos. Along with about 40% more felt recoil if your shooting stuff in the 1,450fps field.
I am done shooting them. Better patterns with the current ammo I shoot and I don't have lead and follow through issues like some. That is why many use it as it can shorten your lead by 8" at 40 yards. For the wear and tear on your gun and body, not worth it. Probably easier on you through a gas gun if you do choose to shoot them.