I’m surprised no one has mentioned Greg Ellefritz’s study on Handgun Stopping Power…
The TLDR; is that most of your common handgun rounds (.380 and up) all stop the attacker with roughly the same percentage, and all averaged near 2 rounds to achieve the stop.
A video recap…
And I think this is the original article
Over a 10-year period, I kept track of stopping power results from every shooting I could find. I talked to the participants of gunfights, read police reports, attended autopsies, and scoured the newspapers, magazines, and Internet for any reliable accounts of what happened to the human body when it was shot.
Since it was my study, I got to determine the variables and their definitions. Here’s what I looked at:
- Number of people shot
- Number of rounds that hit
- On average, how many rounds did it take for the person to stop his violent action or be incapacitated?.. (snip)
Referencing the percentage of attackers being incapacitated after being hit by .22s, he talk about what Active Self Protection now called the FIBS/FIBSA (F*&# Ive Been Shot/F*&# Im Being Shot At) Factor…
In a certain (fairly high) percentage of shootings, people stop their aggressive actions after being hit with one round regardless of caliber or shot placement. These people are likely NOT physically incapacitated by the bullet. They just don’t want to be shot anymore and give up! Call it a psychological stop if you will. Any bullet or caliber combination will likely yield similar results in those cases. And fortunately for us, there are a lot of these “psychological stops” occurring. The problem we have is when we don’t get a psychological stop. If our attacker fights through the pain and continues to victimize us, we might want a round that causes the most damage possible. In essence, we are relying on a “physical stop” rather than a “psychological” one. In order to physically force someone to stop their violent actions we need to either hit him in the Central Nervous System (brain or upper spine) or cause enough bleeding that he becomes unconscious. The more powerful rounds look to be better at doing this.