Concealed Carry & Home Defense

Defensive Carry: Caliber and incapacitation

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By Greg Ellifritz,

As a full-time firearms instructor, I get daily questions from beginning shooters about the “best” caliber for concealed carry. People new to carrying a gun on a daily basis have lots of questions about how bullets work and want to choose the most effective firearm they can carry.

I went through the same learning phase. As a rookie cop who decided to carry a gun off-duty (which isn’t as common as you might think), I obsessed over my personal firearms selection. I started off with a .38 snub because I could carry it as a backup gun on my ankle while working, as well as a primary gun for off-duty carry. I quickly realized, while easy to carry, I couldn’t shoot it very well. Money was tight and I couldn’t afford another gun for a while, so I defaulted to carrying a gun I had owned since a teenager, a S&W Model 19 .357 Magnum with a 4″ barrel. I carried it in an inside-the-waistband holster for more than a year before I got a raise and could buy another gun.

That new gun was a Smith & Wesson Model 3913 9mm. I loved the gun, but I was worried about the stopping power “failures” I heard were prevalent with the 9mm cartridge, so I upgraded to a .40. Shortly thereafter I moved to a higher-capacity .40. Then I upgraded to a .45. I’ve carried just about every caliber available over the years as I stayed on the quest to find the “perfect” concealed carry caliber.

All the while, I was keeping data on the results of every shooting I could find. I went to autopsies. I talked to gunfight survivors and read police reports. I wanted to put to rest all the rumor and propaganda I had seen about handgun effectiveness. I wanted to prove once and for all which cartridge was the “best” — and I would carry that until my research identified something better.


I collected data on nearly 2,000 shootings over the course of 10 years of research. For this study, I excluded all cases of accidental shootings or suicides. Every shot in the data set took place during a military battle or an altercation with a criminal.

I looked at many different factors, but the variables I think most important are the following: What percentage of people shot stopped their aggressive action after one hit to the torso or head? On average, how many shots did it take to stop the attacker? What percentage of attackers did not stop no matter how many rounds hit them?

Before I get into too much detail about the results of my study, a little education in handgun ballistics is required.

There is nothing magical about a handgun bullet, in spite of what makers may say. Handgun bullets don’t explode inside the person shot and they don’t knock someone off their feet. They merely poke holes, and cut flesh. Obviously, where those holes are located on the body is of prime importance. If the bullets don’t hit a vital structure, they can’t physically incapacitate someone. Besides the location of the wound, the other important factor to consider is the size of the hole. A bigger hole is statistically more likely to hit something vital than a smaller hole, all other factors being equal.

No matter where the bullet hits or what caliber is used, a bullets can only stop an aggressor three ways.

Psychological Stop

This is when the attacker stops fighting because of the pain or the shock from the bullet wound. Often, criminals will stop their attack even though the bullet didn’t physically incapacitate them. They just don’t want to be shot anymore! Even though it happens on a regular basis, we can’t rely on this mechanism to reliably stop an attacker. Many criminals are mentally ill or under the influence of drugs or alcohol. Those factors diminish the body’s pain response. We just can’t count on the attacker feeling the pain of the bullet wound and stopping his attack.

Central Nervous System

If your bullet hits the bad guy’s brain or upper spinal cord, it’s likely to be immediately incapacitating, and generally fatal. The only problem with relying on this mechanism to achieve a stopping of hostilities is the fact the brain and spinal cord are relatively hard to hit under the pressure of someone shooting back at you. Besides being small targets, they are relatively well protected by dense bone, which will occasionally deflect bullets.

Blood Loss

If you poke enough holes in vital organs and blood vessels, you will facilitate bleeding. Depending on the number and size of the holes, a person can go unconscious in a matter of seconds from the blood loss (even internal bleeding qualifies here) — or stay in the fight for several minutes. There are examples of people who are essentially dead, staying in a fight for ten or more seconds, continuing to shoot, often inflicting casualties before they actually die from blood loss. Blood loss lowers blood pressure, which robs the brain of oxygen, which eventually shuts them down.

Let’s combine the knowledge we have about handgun ballistics with the results I obtained in my study. It raises some issues involved in your choice of the best caliber for your defensive pistol, so let’s see if we make sense of it.

A modern revolver, like this Performance Center Thunder Ranch revolver in .45 ACP, offers accuracy, ultimate reliability, good stopping power, and fast reloads. A design like this keeps the revolver in the fight when it comes to defensive handguns. Photo: Ichiro Nagata

A modern revolver, like this Performance Center Thunder Ranch revolver in .45 ACP, offers accuracy, ultimate reliability, good stopping power, and fast reloads. A design like this keeps the revolver in the fight when it comes to defensive handguns. Photo: Ichiro Nagata

The Stats

I think the most interesting statistic presented is the percentage of people who stopped with one shot to the torso or head. There wasn’t much of a variation between calibers. Between the most common defensive calibers (.38, 9mm, .40 and .45) there was a spread of only eight percentage points. No matter what caliber you are shooting, you can only expect around half of the people you shoot to be immediately incapacitated by your first hit.

The average number of rounds until incapacitation was also remarkably similar between calibers. All the common defensive calibers required around two rounds, on average, to incapacitate. Additionally, all four common defensive cartridges have very similar failure rates. If you look at the percentage of shootings not resulting in incapacitation, the numbers are almost identical. The .38, 9mm, .40 and .45 all had failure rates of between 13 and 17 percent.

Although this study showed the percentages of people stopped with one shot are similar between almost all handgun cartridges, there is more to the story. There are people who did not stop no matter how many rounds were fired into them. The smaller-caliber rounds (.22, .25 and .32) had a failure rate roughly two to three times that of the larger-caliber rounds.

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 find some useful information. Headshots had a 75 percent immediate incapacitation. Torso shots showed a 41 percent immediate incapacitation and extremity shots (arms and legs) had a 14 percent immediate incapacitation rate. No matter which caliber you use, you have to hit something important in order to stop the bad guy!

How do we use this information to choose a defensive handgun?

While .22s are fun, and have and will be relied upon for defense, Greg’s research showed them to be subpar when it comes to stopping fights against real adversaries.

While .22s are fun, and have and will be relied upon for defense, Greg’s research showed them to be subpar when it comes to stopping fights against real adversaries.

Things To Consider

The “mouse gun” calibers (.22, .25 and .32), while easy to carry, have a very high failure rate as compared to the larger caliber cartridges. If the criminal is likely to be affected by a psychological stop (“Hey, I’m tired of getting shot, so I’ll stop.”), these rounds are as good as any others. I believe that’s why they compare favorably to the larger calibers in the statistic regarding the percentage of people stopped with one shot. Those are likely psychological stops rather than physical incapacitations.

While I agree any gun is better than no gun, I can’t advise you to carry pistols under .35 caliber. They work any many cases, but if you do happen to encounter a motivated attacker, they are far more likely to fail.

.380 ACP

The .380 seems okay from a ballistic standpoint. My only concern is the general reliability of the pistols. They usually just don’t run as well as the larger guns, and people tend to not shoot or practice with them since ammo is often expensive for what you get. Some of the really small .380s are also difficult to hold onto when firing. That contributes to slower subsequent shots. Knowing we are likely to need at least two shots to stop an attacker, this is somewhat of a concern. Reliability and controllability is what helps you with that all-important second shot. If you have a reliable .380 pistol (200 to 300 rounds between malfunctions) and you can shoot it fast and accurately, I would consider it the bare minimum defensive cartridge for concealed carry.

.38 Special/.357 Mag

The .38 Special and .357 Magnum are adequate and superior cartridges respectively. That should make you revolver fans quite happy. My only concern is their rate of fire. Some of the smaller .38 snubs are difficult to shoot well because of their diminutive size, horrible sights and tiny factory grips. The .357 Magnum in a short barrel has very stout recoil and a lot of muzzleblast. Both of these factors make for slower follow-up shots.

Like the .380, I would only carry these two calibers if I had a revolver I could shoot both fast and accurately and could manage a reliable reload. Remember, you don’t have high capacity magazines (or those 8-shot revolver cylinders) so you have more ammo — it’s so you don’t have to reload as often!

9mm, .40 & .45 ACP

That leaves the 9mm, .40 and .45.  There is a remarkable similarity in performance between these three rounds. They all stop about half of the attackers with one shot, and have a failure rate of 13 to 15 percent. Despite all the bluster you see on the Internet about not carrying a defensive pistol unless the caliber “starts with a 4” — the .40 and .45 do not perform significantly better than the 9mm in real life gunfights.

That doesn’t mean the .40 or .45 is a bad cartridge, it just means these cartridges don’t live up to their hype. While at the top of the heap, the .45 is far from a stopper 19 out of 20 times, as Jeff Cooper was fond of asserting.

I would feel completely comfortable carrying any of these three cartridges as my primary defensive weapon. Rather than worrying about the inconsequential differences in stopping power, I would focus on finding the most reliable and accurate firearm I could carry in any of those three calibers. If you can hit with it, and manage fast follow-up shots, and it’s reliable, don’t let caliber confuse you.

Equipment Not Caliber

As I said in the beginning, I’ve carried just about every caliber imaginable during my career. My extensive research has caused me to worry less about caliber — and more about reliability, ammo capacity and rapidity of follow-up shots.

For the last 10 years I’ve primarily carried a 9mm Glock as a concealed carry pistol. But I do occasionally carry a .380 or .38 snub. My police duty gun is a .45. I feel comfortable with all of them, but on my own time, I carry the Glock 9mm about 90 percent of the time. It’s a great combination of accuracy, reliability, stopping power and capacity. That’s all you can ask for in a defensive piece.

My recommendation to you is to ignore all the advice you receive from gun store salesmen and Internet keyboard commandos, unless you personally know their info to be sound. Choose a reliable gun you can carry all the time, and shoot both fast and accurately. Caliber simply isn’t all that important. Imagine that.

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About the author: Greg Ellifritz is the full-time firearms and defensive-tactics training officer for a central Ohio police department and the president of Active Response Training. He holds instructor or master instructor certifications in more than 75 different weapon systems, defensive tactics programs and police specialty areas. Greg has a Master’s degree in Public Policy and Management and has been an instructor for both the Ohio Peace Officer’s Training Academy and the Tactical Defense Institute. He can be reached through his website at



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