When I did expansion testing on Hawk Bullets in my 404J, every single bullet separated the jacket from the core. When I contacted their engineer, he blamed it on yaw. Either via bullet alignment to the bore as part of my reloading methods or not enough twist rate.
My expansion test is dry magazine to simulate heavy skin, wet paper for fresh, 1.5" tree branch ( bone), a substantial amount of wet paper material to simulate a 20-24" wide chest cavity, finally water jugs to capture the final projectile.
Only one core made it to the first water jug. 2 bullets failed on the branch.
Woodleigh RN and A-Frames all made it to the second water jug.
I'm not a fan of "finding out" how a bullet performs on game. I prefer to know beforehand. Taking an animal's life shouldnt be an experiment (IMO).