A fellow hunter with a degree in fluid dynamics suggests to me that the diameter of the bullet may be proportional to the sensory impact percieved by the target to some finite enlarging bullet diameter where CNS neurons are saturated for a "knock out". Thus 500 is felt more than 458 etc,etc.This is somewhat velocity independent, ie faster bullets with more energy/momentum still dont give more sensory input just making the impact hole!!

Further extension of these thoughts is that the animal CNS effect does exists and a larger cross sectional area bullet works better to a point. We must also obviously add penetration to vital structures to kill effectively and efficiently. Momentum matters critically and signifigantly here. All the animal percieves is the impact and the defecit from the lethal damage to vital structures. A similar analogy can be made with enraged attacking individuals shot by firearms. They must first recognize they are shot to possibly stop their attack.If not vital structures must fail for success.

If we have enough velocity and penetration a flat nosed solid theoretically should work better than a round nosed bullet at transmitting proportional disruptive energy around the tissues of the bullet path thru the animal.Theoretically, I would prefer blunt nosed solids if penetration is ok. Lacking adequate penetration round nosed solid would be preferable.

All this is just theory and to some-just BS. Of course if you put the bullet in exactly the right place all this is irrevalent and we should all be hunting with 6.5mm's etc.

Big bullets in the right place seem to work every time!!!