Bullet impact should be different for every animal.

I think that to be effective bullet impact should be less severe as the animals get larger. I say this because the severity of impact is governed by how quickly a bullet transfers it's energy into the target. So the faster the bullet transfers energy, the faster the bullet slows down and stops. On bigger animals you want the bullet to penetrate as deeply as possible.

Obviously this is the reason there are increasingly larger cartridges shooting larger bullets so you can hit bigger animals with more impact and penetrate a deep as possible, but as a standard rule, I think impact should be greatest for smaller animals and least for larger animals. Any other thoughts out there?