knockdown power... fact or myth?

I guess it all depends on how you define it. However, as portrayed by Hollywood, where a guy catches a shotgun blast and is literally picked up and carried away, is HOGWASH (or something less polite!!) If you subscribe to Newton's Third law of Motion, no projectile can ever deliver a greater blow to the target than is evidenced by the recoil effect in the opposite direction.

For example, some people thinkthat "a .45 ACP bullet will knock a man down regardless of where it strikes him". This too is B.S.! I once watched a demonstration at Fort Bragg NC in which one sergeant fired GI .45 APC Ball ammo at another sergeant's hand who was equipped with a Kevlar "catcher'smitt", with which he was CATCHING THE BULLETS and holding the mitt out palm up so the audience could see the bullet he just caught! Range, about 15 feet. Each time the bullet impacted the mitt, his hand jerked backward some, about the same amount as did the hand of the guy shooting the pistol! I therefore assume the mitt weighed about the same as an M1911A1.

The only time a knockdown occurs is when something is done to the quarry by the effect of the bullet that prevents the critter from continuing what it was doing when hit. This effect generally involves damage to, or at least temporary interuption, of its' nervous system - not necessarily a brain or spine hit, but a shockwave that effects its' nerves in a massive sort of way. For example, I have shot black bears that fell at the shot, then got up and ran a short distance before keeling over, deader than a doornail! Were they "knocked down" by the bullet? Nope, not physically. But the nervous shock of the bullet passing through their chest cavity was sufficient to short-circuit their system for a short period of time. They recovered from this shock, recovered muscular control, got up, and started to run away before the lack of oxygen from the destroyed heart & lungs caused their system to go offline permanently.....

Hollywood aside, I think the myth of "knockdown power" may be promoted by the ballistics tables, which show kinetic energy figures in terms of "foot-pounds of energy". This term is defined as "the number of feet that particular amount of energy will move a 1-pound object if all the energy is expended on the object." Now, who believes that a bullet carrying "3000 foot-pounds of energy" will actually move a 1-pound block of some material that traps the bullet in it3000 feet downrange? Or that a 100-pound object will be moved 30 feet? If you believe this, I have A slightly used bridge in the vicinity of New York City for sale cheap.....

Maybe what we need is a new system for measuring bullet energy. For example, we all admit that a .22 caliber, 55-grain bullet rated at 1500 foot-pounds of energy will do an entirely different job on a woodchuck than will a 400-grain .45/70 bullet carrying the same ft/lb rating.....

One is an elk load, while the other obviously is not!