That is just weird. Weird things do happen though. Perhaps a faulty batch or something, bit of a head scratcher. Weirdest thing I've seen wasn't bullet failure, but a whitetail buck's "failure" to die as swiftly as all logic dictates he should have. This was with a 270 at about 150 yards, old reliable hornady interlocks 130 grain at 3200 fps muzzle. I can't image that a .30 cal magnum or really anything short of a cannon would have visited more violence upon the creature. Evidence of completely violent expansion WITH an exist wound that, under the skin, was over three inches wide, with a a two inch shard of shattered rib bone laying in the snow 6 feet behind where he was standing. That super vivid BRIGHT red spray extending out to said rib chunk indicating at least one destroyed lung. It was quartering downhill towards me, bullet entered through a shoulder, completely destroyed that quarter of meat unfortunately, upon field dressing it was revealed the side of the heart got clipped, perhaps by a fragment, and one of the arteries was completely severed. And as I mentioned, offside lung completely destroyed, with a huge free bleeding exit wound. Better bullet performance is hardly possible as far as lethality is concerned. That buck I tracked over half a mile and when I found him bedded down he started trying to get up again, shot him in the head and finished the job. There was no blood left to drain, to this day it is beyond me how this happened, all
I know is it did. I felt sick the whole time I tracked it, assuming that somehow I had made a bad shot (though the rib bone and lung spray made me confused as to how), because surely an animal with no shoulder, effectively no heart, one lung, little blood left, and a huge hole in its side could not run over half a mile!!!