Well to get back to the original topic of KNOCK DOWN power ,I am inclined to doubt that there is any such thing.
There is FPS of energy, and brain and spine hits that kill instantly, there is also hydrostatic shock and when the mushrooming bullet is placed on the group of arteries over the top of the heart but very close to it or on the carotid artery in the neck, you can get an instant kill, especially if the game has not been startled.
I realize that I have opened a can of worms, but this is a subject that could use a bit of discussion and it is in line with the original topic.