That cow weighed around 475 on the hoof, from calculations we made after weighing the parts.
Generally, if an expanding bullet opens as all, it expands by the time it penetrates its length, which with most is 1.5 inches or less. My experience with TTSX's is they do open more violently than TSXs, and those we've recovered have opened a little wider, or even lost some petals.
The one that killed the elk lost ALL its petals, so "only" retained 62% of its weight. But it killed very quickly. Personally, I have never found much correlation between higher weight or petal retention of Barnes X-Bullets and how well they killed, though a lot of hunters seem to consider both both important. (Same deal with other monolithics.) Some of the fastest kills I've seen with various X-Bullets involved bullets that lost most or all their petals, probably because they hit bone, which fragmented and also caused some damage.
