I came across this video linked from a YouTube teaser leading Full30.com, that shows an account with full dissection of the target animals, revealing the damage that Underwood Xtreme Penetrator does in living tissue, in hunting situations on deer, using .45-70 and .357 ammunition. The results are very consistent with what I have observed in my own tests on pig carcasses weighing between 150–200 pounds, as I described in the following post:
It is also quite consistent with the live animal shootings that I have knowledge of that I have referenced, including a 600-pound bear in Alaska in this post:
Just for clarity, here is the link again to the hunting video with the Xtreme Penetrator rounds:
In the video, you will note that these quite experienced hunters are rather dumbfounded at the amount and type of damage that these rounds did, which exceed that done in their experience with more traditional hollow-point and cast lead rounds, from what I can determine.
The damage, especially the "secondary" wound tracks resulting from flung-off pieces of shattered bone and tissue that has been essentially "jet cut" from the high-velocity fling-off coming out of the flutes in a Venturi-effect-jet of pulverized tissue, bone fragments, and body fluids. To quote myself here, this round not only cause(s) tissue and structural damage due to the penetration of the bullet, but (also) cause(s) rupturing and tearing due to the violence of the non-compressible fluid (blood and other liquids) being rammed out of the way by the transferred force of the bullet.
If you have had uncertainties and doubts about how this round performs in actual, live tissue, which would obviously include two-legged creatures, this should provide you with some clarity on how truly devastating the Lehigh Xtreme-type rounds are.