I quite sure he would be knocked down by a .22 lr round fired into a vest
I'm not so sure I wouldn't be knocked down by a .22LR round fired into a vest!
I've never been shot by a .22lr fired into a vest, so I don't know, for SURE, but I think it might be likely, if I didn't expect it. (and since I'm a LONG way from 25 and the peak of health and balance, its quite possible!)
One of the funnier things I've ever seen was a news clip that was in a "bloopers" show I saw ages ago.
An reporter, standing in front of the camera, holding his mic and wearing a bulletproof vest over his suit jacket. The reporter tells us about the new vests the local cops are getting, and how they "really work" And then he says, "and to prove it, I'm going to let them shoot me!!!"
At this point, a hand holding a small shiny revolver (nickle or stainless) appears out of the right side of the frame, distance a couple of feet away.
There is a POP sound (all gunshots become "pops" on video tape) and no apparent recoil of the revolver.
The reporter staggers back several steps, stumbles and falls, dropping the mic. He slowly gets to his hands and knees, picks up the mic and stands up, and we hear a slightly muffled "Oh F(bleep), that
hurt!!"
I do not think the reporter had been adequately briefed on what was going to happen. He wasn't incapacitated, but he was KNOCKED DOWN by the little round hitting the vest.
The bullet didn't physically knock him over, but he was knocked down by his own reaction to being shot.
Plug that into various formulas and see how it computes!
I've talked with people who have been shot. Some describe it as a "hammer blow", others said "a fierce burning sensation", one guy (a cop) said he didn't even know he had been shot, until after the gunfight was over....
Everyone is different, and some people are very different. I don't think there is any math that can take that into account, accurately.
Formulas and statistics may be useful for comparing different rounds to each other, but their accuracy in predicting real world results is 50/50, each and every shot. The real world either behaves in line the formula, or it doesn't.
Flip a coin, its just as accurate a predictor...