What a bunch of confusing answers. Some are talking about ballistic tips and some are talking about boat tails. It’s like comparing apples to coconuts.
I use Hornady SST’s for deer (.243, .270, 30-06). At close range (100 yards or less) they sometimes fragment and sometimes they don’t . It depends on where you hit the deer. I have alleviated the fragmentation problem by shooting them in the head.
I also use flat based bullets because they have better accuracy at close range (most shots for me are a 100 yards or so) than boat tailed ones that are designed for accuracy at longer ranges.
I also fail to see any correlation in bullet expansion between flat based and boat tailed.
Those who beat their guns into plows, will plow for those who don't.-Thomas Jefferson