In fact there's dozens of thought trains but in the final analysis there's two basic theories on bullet performance.
1. The hunter wants a fragile bullet that does not exit the animal. He wants the bullet to mushroom well and penetrate to the far side of the animal and not exit. Not exiting is the proof that the bullet expended all it kinetic energy in the animal. This helps to assure that hydrostatic shock kills the animal instantly!!!

2. The hunter wants the bullet to mushroom and do as much destruction to tissue and internal organs as possible and still have the momentum to exit the animal. The reason he wants an exit wound is because he knows that there's absolutely no guarantee that the animal will expire instantly and will run a distance.....the exit wound leaving a well defined and easy to follow blood trail.

For the many years I was following theory one.....then I changed over night and now subscribe to theory two.....

Where are you and which bullets fit which theory?