Many of the early Barnes X's (pre-TSX) also lost their petals. Hunters complained, for whatever reason, which puzzled Randy Brooks somewhat, because he hadn't found petal-retention made much difference in the way they killed or penetrated. But he decided to make customers happy, so fooled around with the design until they retained most petals, most of the time. This made people who judge bullet performance on weight retention happy.
I've shot a bunch of X's, TSX's and TTSX's into big game animals, along with various other petal-type bullets, some actually designed to lose their petals. Like Randy, I never noticed much difference in on-game performance, but no doubt many other people will disagree.
