I kinda had the opposite experience with the SST's. Out of a .270 Ackley at about 3,350 fps, the 130 grain SST worked pretty well on an antelope. On a big whitetail buck at 400 yards, it expanded quite a bit - more than I would have expected due to the distance. But on a cow elk at about 150 yards, it exploded in the shoulder. Second shot hit the spine just behind the shoulder, and that one exploded as well. In that caliber at least, I thought they were too soft for animals bigger than deer size.