I agree with Paul. All this knockdown stuff on deer is a myth. The only thing a bullet will knock down is perhaps some small target made ofsomething so dense (like steel) that the bullet can't penetrate it. I have killed a lot of deer with a rifle and seen a lot more killed with everything from a 22-250 to 300 WM. I've never seen one knocked backwards by a bullet. What I have seen is a deer occasionally drop straight down on impact. People often refer to this occurance as "knocking the deer down" but this phrase should not be taken literally. A bullets mass and frontal area is just so small that it reallyisn't able to impartmuch of a lick before it starts to either penetrate, fragment or deflect depending on the physical makeup of what it strikes. Any and all of which virtually reduce its straightline knocking ability down to a very low level despite all the footpounds of energy generated by it's high velocity.