I have mixed feelings to report on these bullets. In faster hi-power rifles like my .280 Rem, they tend to blow up at close range, even more than your standard soft point. On a 130# doe shot at 35 yards, the 139 grain sst exploded as soon as it entered, no bones(other than ribs) were hit. Deer did die but I found fragments of the bullet in the deer. Exit hole from one small piece of lead approx. .223 size.
Deer #2 100lb doe shot with very different weapon, 12 gauge shotgun. 300 grain SST, 70 yard shot bullet went thru over 2 feet of deer, no fragmentation, deer dropped in tracks. Exit hole size of golf ball. No bones(other than ribs) hit. Conclusion- SST's are better in larger calibers and do better at medium to long range.