You just answered your own question. It does not exist. There isn't a single bullet or cartridge that can be relied upon to "knock down" any animal. The only sure drop them in their tracks shot is a spine or brain shot.

Everything has to be just right to drop an animal in its tracks with a chest shot. It usually is a result of extreme shock to the circulatory system. Enough to cause massive shock to the brain from the massive shock traveling through the blood vessels from the bullet.

Now a shot through both shoulders will drop them on the spot but they will not be dead.




This past week I took a deer with my bow. Now most people would not consider a bow to have "knock down power" and I agree 100% but the deer never took another step. It droped right in its tracks. Why? Because I shot it straight down through the spine. Is this knock down power? of course not. It's severing the brain from the rest of the body.

This is just an example of how any projectile can be thought of as having "knock down power". However it simply does not exist.