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Departments : Officer Survival

Understanding Stopping Power

Choosing a defensive handgun requires you to balance power and accuracy.

January 01, 2003  |  by Roland C. Eyears

Gelatin block studies are a good way to determine the impact of bullets on living tissue and a graphic representation of stopping power.

If I knew I'd be in a gunfight within the next 20 minutes, I'd be laying my hands on a 12-gauge. But the best I can predict is that, as an officer of the law, I might be in a gunfight sometime in my career. So I carry a handgun.

But the question remains: Outside of a "street howitzer," which gun and which cartridge is best in a gunfight? In other words, which combination yields the most firepower?

Today's commonly accepted definition of "firepower" is a large-capacity magazine and a rapid rate of fire. But this doesn't take into account the effectiveness of the rounds fired. And that is, of course, the most critical concern.

Suppose you allowed me to land a series of 25 mild punches to your solar plexus over a period of a couple of hours. What would be the net physical effect? Now imagine that the kinetic energy of all those blows went into a single hit. The aggregate force would be equal. But is there any doubt how the result would differ?

What I'm saying here is that high-capacity magazines are nice, but police shootings average about 2.8 rounds in 2.5 seconds, with all parties heard from. Therefore, in evaluating defensive handgun choices, the number of rounds available is not the way to determine effectiveness nor define firepower.

Shutting Down a Threat

Let's agree that no rational person wants to get shot with anything. But getting shot in the real world doesn't have the same effect that it does in TV shows and movies. In such entertainments, police wing the bad guy and the bad guy goes down. It can happen that way, but don't bet your life on it.

Shooting a human being is much messier and much less precise in real life than it is on TV. For example, fat can protect organs and plug holes, preventing external bleeding and encouraging the attacker to ignore the wound. As for pain, don't count on that to shut anyone down. Nature has a reason for programming us to lose an arm and feel only a tingle or numbness. And remember, your attacker may be on alcohol, stimulants, PCP, or he or she may be just plain strong and mean enough to take a bullet and keep coming.

If you find yourself in a shooting situation, your goal is involuntary physical shutdown of the person who threatens your life. And to do that you have to hit your attacker with your shots and hit him hard.

Shock Waves

The Model 1911 .45 ACP semiauto is many a shooter’s choice for both power and control.

Lots of factors-mass, design, velocity-go into determining how hard a bullet hits. And there are a lot of misconceptions about how they all contribute to stopping power.

For example, much has been written about the hydrostatic shock produced by energy dump when a bullet fails to exit the body. It's been posited that such shock waves open a devastating, temporary wound cavity far larger than the bullet diameter. But at handgun velocities, how damaging can these shock waves be? The answer is not very.

Col. Martin L. Fackler, MD-through his unparalleled opportunities as a U.S. Army surgeon to observe and treat the results of thousands of small arms hits-is probably the world's leading expert on wound ballistics. He argues that the elasticity of most tissue prevents serious trauma from hydrostatic pressure.

A related claim involves sonic wave damage. Fackler disputes this as well. He points out that the device used to sonically break up kidney stones produces over 1,000 sonic waves per treatment at three times the amplitude generated by a handgun round, but it doesn't traumatize the surrounding tissue.

33 Rounds

So what does it take to shoot and stop an attacker? Fackler and other experts say it can only be accomplished two ways: destruction of a vital organ such as the heart or a vital body structure such as a hip joint.

The fact is, even if we shot all the test animals we could afford and even put a few rounds through a few human volunteers, we still wouldn't know precisely what it takes to stop a given attacker in his tracks on a given occasion. The civilian record stands at 33 rounds, and all of that trauma didn't cause instantaneous shutdown.

One of the most carefully dissected incidents in modern gunfighting has been the 1980 Kolowski-Burchette encounter in Illinois. This unscheduled 30-second field test of 115-grain, first-generation Silvertips occurred when two state troopers stopped convicted felon and suspected killer Wayne O'Brien.

In the ensuing gunbattle, the heavily muscled and very drunk O'Brien took 13 rounds. He absorbed two hits in the cardiac sac, with one of them slicing his aorta. In addition, two slugs ripped through his neck, and others punctured his stomach, his lungs, a kidney, and his liver.

Yet with all that damage from police handgun rounds, most of which demonstrated excellent penetration and expansion, he fought on as if merely annoyed. Then he returned to his bike and died. With a fully oxygenated brain and glands pumping, the man had maintained aggression for perhaps 12 to 18 seconds after his heart had been pulverized.

You may be thinking all the Illinois troopers had to do to stop O'Brien was "shut down the computer." But it's not that simple. Examples abound of headshots that got people's attention but failed to discourage them promptly.

And the issue always comes down to two factors: size and power of the bullets.

Imagine that you've been immobilized and a rigid metal frame has been strapped securely to your right chest. Two guide rings, one a half inch and a second 10 inches from your chest, will accommodate a surgical steel metal rod to be driven at high speed by a piston. As quickly as it is driven 12 inches into your body, it will be withdrawn. If you had to choose, would you prefer a rod of .17 inches in diameter or .60 inches?

The lesson from this example and from dozens of real-life gunfights is simple: size matters.

Brain Waves

What are the psychological aspects of stopping power? Does a bullet entering your body throw the mind into shock? The answer is maybe, and maybe not. Even a grievous wound may not convince an attacker to stop.

It's all a matter of why the attacker is  fighting. And to understand this principle, consider the following:

You're walking through the park with your 9-year-young daughter when a man with a .45 approaches and tells you exactly how he intends to sodomize her and then bury her alive. He orders you to turn and walk away. Instead, you lunge as he puts a round through your upper left chest. Do you let the psychological impact of being shot stop you?

Retired police detective Evan Marshall has studied thousands of actual shooting incidents, all different and all reported in such detail as the participants could or would recall. And the one thing they reveal is that if the person being shot has strong motivation to continue his attack, i.e. save his daughter from a fate worse than death, then he will probably keep charging as long as he is physically able.

Comments (4)

Displaying 1 - 4 of 4

Samuel, Reich @ 7/6/2013 8:17 AM

If your aim point is the chest and you are not shooting through barriers: Human lungs have a density only 1/3 that of water and there is only 2 or 3 inches to get inside the chest cavity. Therefore in that case rapids expansion is much more important than penetration.

m2foster @ 7/18/2014 6:02 AM

Human lungs are also protected by ribs which would require that you shoot them between the rib spacing, and since the lungs are located above and outside the center of mass where most people are trained to aim, wouldn't you be relying on luck to get that shot where rapid expansion is a bigger factor than penetration?

gsparesa @ 11/20/2014 4:29 AM

I believe that I found an error in your muzzle energy calculation description. You forgot to take 1/2 of the bullet weight times velocity in feet per second squared. The formula according to Wikipedia:

Ek = 1/2mv^2 * (1/7007*32.163)
Ek = Muzzle energy in ft-lbf
w = Weight of bullet in grains
v = Velocity in FPS
7000 gr per avoirdupois pound
32.163 ft/s^2 acceleration due to gravity

Given the above formula, I calculate that the muzzle of a 230 gr 45ACP to be 351.88 Ft-lbf and not 345 as depicted in the chart.

Chris @ 6/21/2018 11:07 PM

Did you completely disregard the .357 Sig for any particular reason? Also from whats been shown the .40 S&W has exceeded the .45 ACP in velocity at the very least.

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