ORIGINAL: 8mm/06

I don't see it as a debate...it isn't Speed vs Weight..
You must have the appropriate combination of velocity, bullet wieght, bullet construction and point of impact. That is what kills.

2 rifles shooting the same wieght and construction of bullet but at DIFFERENT speeds will have varying terminal results.

You can change the variables all you want but in the end you will find that certain COMBINATIONS are more lethal than others.