Creating the largest wound channel is what does the killing. How the bullet reacts to the impact is the key to creating the wound channel. Square fronted non-mushrooming solids create the largest wound channel because they displace tissue perpendicular to the bullet's path, and penetrate fully, because there is no loss of mass, or increase in diameter.
So it seems that the bullet that retains the most velocity after impact and deforms in such a way that it displaces tissue perpendicular to it's path is what we are after.
I agree with an earlier statement that more or less said there is no such thing as knock down power. If there was it would knock down the shooter 1st.
Now the trick is to pick the bullet that will be stable in flight, fully penetrate and create the wound channel proportionately large enough to kill the size of the game animal being shot.
What it comes down to for me is what part of the dangerous game solid do I
want to compromise in order to hunt further down range?
This stuff is hard for me to figure out, because for the sake of the animal, I don't want to figure it out by trial and error.
To hunt... or not to hunt...? What a stupid question.