I'll digress from the original thread for a moment...
the .45 doesn't just knock them down, it sends them flying backwards through the air and they land stone dead
I love hearing stuff like that. It's great fiction; not even close to reality. Every once in a while I hear something like that from an old combat vet, and I politely nod my head and thank them for their service to our country. I'm a combat vet myself, so I could debate the point, but if they remember seeing the guy fly 10 feet backwards, landing spread eagled and stone dead, then that's their memory, and I won't try to convince them their memory isn't really possible; not with most military sidearms anyway.
Let's think about this for a minute. You have to use pretty stout loads to knock down bowling pins (regulation pins weigh about 3 1/2 lbs); now think about that load striking a human weighing 40-50 times (or more for some of us) the pin .
I saw one author who did a great job of demonstrating how the whole flying through the air thing was impossible. As I recall, the author put the kinetic energy in context by comparing the kinetic energy of a bullet with that of a baseball. Basically the energy calculations show that in a typical line-drive hit, a baseball will carry something like two or three times as much energy as a 45ACP bullet fired at close range.
Now I've been fortunate in that I've never been hit by any lead sent my way. But, I have been hit with a hard line-drive a few times, and it was a bit painful, but it didn't knock me anywhere. If I fell down (not flying backward mind you), it was in reaction to pain, not because of the energy transfer.
It boils down to basic physics. A 230gr 45ACP bullet does not carry enough kinetic energy to knock down a human being (maybe an infant or toddler), much less make them fly anywhere.
Anyway, I'm not trying to criticize anyone here, just point out a favorite myth about "knock down power".