Supposedly they won't go through the vests that Police wear. But, in watching the video of them in action it looks somewhat similar to being hit by six pellets and a slug from a small shotgun. I wouldn't want to be hit by one of those. I'd imagine they'd give ER physicians a hard time cleaning up the damage before the patient expired.
Problem is, this works like a frangible round (which is what it is, I guess). It's only 96 grains to start with, and the petals shear off when it impacts the target. You want a bullet to retain mass while penetrating, not shed it within the first couple of inches. You're left with only a tiny little chunk of metal that continues to penetrate. That will cause an ugly, shallow wound, kind of like shooting someone with birdshot (hopefully no one wants to start the whole "birdshot is the best for self defense" argument).
Basically, this bullet combines the worst aspects of FMJ and Frangible ammunition. Most of it fragments on impact, while the rest just icepicks on through.
