Shot Placement vs. "Stopping Power"

Torso Lethal Shot Placement

It happened again to me. I was looking through a firearms magazine last night, reading the letters to the editor, and there was someone that wrote that the appropriate caliber for a defensive handgun should always start with a "4", and then used the same old polemic of the only reason for a high capacity magazine for a 9 mm is because it takes more rounds to do the same damage as a single shot from a .40 S&W.

Frankly, I thought the debate was pretty much over--all handgun rounds are pretty marginal, so shot placement counted for more than "stopping power." For instance, Greg Ellifritz has done a statistical review of shootings, published on the Buckeye Shooters Association site. He writes:

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.

I documented all of the data I could; tracking caliber, type of bullet (if known), where the bullet hit and whether or not the person was incapacitated. I also tracked fatalities, noting which bullets were more likely to kill and which were not. It was an exhaustive project, but I'm glad I did it and I'm happy to report the results of my study here.

His results showed that, statistically, the .22 LR compared well against other firearms. Why? Ellifritz concluded:

What matters even more than caliber is shot placement. Across all calibers, if you break down the incapacitations based on where the bullet hit you will see some useful information.

Head shots = 75% immediate incapacitation
Torso shots = 41% immediate incapacitation
Extremity shots (arms and legs) = 14% immediate incapacitation.

No matter which caliber you use, you have to hit something important in order to stop someone!

In other words, with handguns, shot placement (i.e., accuracy) is far more important than caliber.

Breach, Bang, Clear has a guest article by Aaron Cowan that discusses the physiology of why this is so. Cowan writes:

How many rounds does it take to stop a threat? The only correct answer to this questionis “as many as it takes to gain compliance, surrender or incapacitation.” 

That is the only correct answer. 

Let’s de-sterilize that word incapacitation: Incapacitation in our context means death, unconsciousness due to blood loss or central nervous failure resulting in the loss of bodily control. It does not mean on the ground unless on the ground includes one of those three conditions. 

How long does it take to truly incapacitate someone? The only guaranteed instantaneous incapacitation is in the head; the brainstem. Every other location of the body is a delayed incapacitation at best. What about shooting someone in the heart? Well, the heart is a muscle and outside of large caliber rifles, bullets are not big enough to totally explode the heart. Assuming that a round fired from a normal defensive weapon could totally explode the heart, your bad guy still has time to fight because his brain and limbs will have enough oxygenated blood in them to allow him to fight. Cutting all blood flow to the brain, your bad guy has up to 10 seconds until unconsciousness and approximately 20 seconds until total electrical failure4. That’s a long time – especially if that person is trying to “incapacitate” you. 

What about massive bleeding? Since it’s (very damn) rare to totally explode the heart or totally sever major arteries, and because the body acts as a barrier to blood loss, the loss of blood will have to reach about the 30%-40% range before incapacitation can be expected. In order to cause severe blood loss, we have to hit major organs and arteries. The average resting cardiac output is 5 liters a minute (for an example 154 pound man); imagining a major hemorrhaging (level IV) from a sufficient diameter wound, it will take our mope at least 20 seconds to lose 40% blood volume. Remember that even once that happens we have the above mentioned loss of oxygenated blood to the brain to confront. 

Blood does not flow at this rate because cardiac output does not equal bleed rate from point of injury. As blood loss increases, pressure drops, though cardiac output can be expected to increase under stress. These two facts complicate each other, making a prediction difficult. Even going with the best case scenario (outside of a brainstem hit), incapacitation is going to take time and that time is dependent on how well you shoot, how deep the rounds penetrate and what they hit inside the body. Even suffering a fatal wound, your bad guy can continue to fight until system failure; Ambulation after Death is common and should be expected (seen in Tim Gramins shooting earlier in the article).

... We have three general zones on the human body for the sake of shooting; head, chest and pelvis. I list these in general order of importance. 

The head is where the off switch is located. The brain is our software; it controls everything and is dependent on a sort of harmony to work effectively.   That harmony is easily disrupted by bullets. 

The brain is our ideal target if distance, skill and circumstances allow for the shot. ...

 Cohen goes on to describe why the chest (or high thoracic cavity) is secondary--it does not have an "off switch," but strikes there will generally lead to heavy blood loss. Incapacitation will take longer than shots to the head. Finally, he mentions pelvic shots, but notes that there is little information on the effectiveness of a pelvic shot. There is a lot of good information in Ellifritz's and Cohen's articles, so I recommend you read both of them.

One thing I would note about the pelvis shot--although it may not result in "incapacitation," as Cohen uses the term, pelvic shots are often used in hunting bear in order to fix or pin the target. That is, the animal is not dead or unconscious, but it is difficult for it to continue moving toward you if its pelvis is shattered. (For the same reason, some unarmed self-defense instructors recommend a kick to attacker's pelvis to try and break the bone). A second shot to a vital area is then used to kill the animal. I'm sure the same theory could apply to the human animal.

Finally, I would note that if you go to Sage Dynamics web-site, on the bottom of the main page, there are links to download vital anatomical targets for the head and the chest.

(H/t The Firearms Blog)