While doing some research, I noticed something interesting about the Federal HST 9mm loads. With most 9mm loads I've seen, the 124 grain +p load generally penetrates shallower but expands more violently. However, it looks like the HST may be different. In several tests, the 147 grain HST actually expanded more than the 124 grain version while still getting a little deeper penetration. I mean, these things are nasty little SOBs. It looks like they regularly reach 0.70" + even with denim while the 124+p usually stays in the .60" range. Why is this? Totally breaks the trend for 147 grain bullets not expanding well.