The most up-to-date values for today’s most bought and sold firearms. Get Your Copy

Probably the most hotly discussed topic in personal defense is the argument over what constitutes a proper concealed carry caliber.

We know that no caliber chambered in a regular repeating handgun is capable of always stopping a perpetrator with a single shot. Obviously some calibers are much more effective than others, but there’s always a trade-off in recoil, capacity and the size of the carry gun. It’s a common belief among many that any caliber under .40 is ineffective, and those who carry smaller calibers are constantly bombarded with anecdotes relating to the dire consequences of carrying a pipsqueak caliber.

Statements about chocolate grips and filed-off front sights abound, but there’s really little evidence to prove that bigger calibers are substantially more effective in stopping aggressors than smaller ones.

With the exception of hitting the brain stem or first few inches of the spinal column, handgun calibers incapacitate by causing blood loss. Larger, more powerful calibers are more likely to accomplish this given the same entry location and angle. Ideally, the projectile should penetrate to vital organs or major arteries even if they encounter bone structure. It’s a given that the larger the wound channel, the greater chance that wound channel will intercept those large arteries and vital organs, so a combination of penetration and an enlarged wound channel is the criteria for best performance. It’s better for the projectile to stay in the perpetrator’s body, for two reasons: One, if the projectile doesn’t exit, all the energy will be transmitted to the target. Second, since personal defense often happens in populated areas, a projectile that doesn’t exit can’t do damage to an innocent bystander.

Since the penetration to the spinal column is a major factor in incapacitating a target, and most defensive situations involve a frontal shot, it would be ideal to somehow push the projectile all the way through the perpetrator with it stopping just short of exiting. Unfortunately, such consistent performance isn’t possible because bad guys come in different sizes and wear different kinds of clothing, which can be a factor in penetration, especially if the bad guy is wearing heavy winter clothing.

It’s been generally accepted that .38 Special and 9mm are about the minimum in reliable stopping power. In recent years, the performance of .380 ACP has been improved with better bullet design and higher-performance defensive loads. Traditionally, there’s always been a school of thought that the .45 ACP is a reliable one-shot stopper. As a young man, I heard stories from World War II veterans about enemy soldiers being hit in the shoulder with a .45 slug and the impact flipping them into a distant foxhole. While early TV shows depicted those who were shot simply freezing in place and dying, later TV shows and movies popularized the concept of bad guys being thrown over cars and across rooms. Neither scenario was realistic. People who are shot react differently, but violent movements come as a reaction from the person who’s received a gunshot, not from tremendous energy being released against their body.

The energy of a handgun round is simple physics. If enough energy is released from the muzzle of the handgun to knock the aggressor down, the recoil from that shot will have a similar effect on the person who fires the gun. Even a .500 S&W only deflects my arms when I shoot it. It’s quite easy for me to maintain my balance and stay on my feet. A 230-grain .45 ACP round only moves my arms slightly, with most of the movement being absorbed by my arms.

Most accomplished shooters can easily handle a full-size .45 or .40 with little adverse effect. That number is reduced, however, when the size and weight of the gun goes from a 39-ounce, full-size gun to a 20-ounce concealed carry pistol. My experience is that even individuals who consider themselves perfectly capable of handling a gun in a caliber that begins with “4” often flinch enough to cause shots below the targeted area, even at close range. Further, continued practice with a gun larger than you can handle often exacerbates the problem of flinch. A shot that hits below the sternum is unlikely to cause massive blood loss, even if it’s a fatal shot. Massive blood loss is your best bet for making a determined aggressor cease to fight.

A while back, I had a conversation with the sheriff of a Georgia county who had recently switched his department from the Glock 22 in .40 to the Glock 17 in 9mm. His reason for the switch was that many of his officers were having trouble managing the additional recoil of the .40 S&W round. When the department made the switch, the qualification scores for the department went up substantially. He also made the point that the less expensive 9mm round allowed the department to purchase almost twice as much ammunition for practice at the same budgeting level.

Weight is another problem with large-caliber concealed carry guns. They tend to be heavy. The primary prerequisite to winning a gunfight is to have a gun. Of the guns in calibers that begin with “4,” about the lightest models available weigh around 20 ounces empty. Most .38 Special five-shot revolvers weigh in between 11 and 14 ounces, so the average weight reduction is close to 40 percent, a substantial difference when you carry every day, all day.

Bigger guns are better stoppers, but they weigh more and are harder to carry comfortably. Every choice involving concealed carry is a compromise, but modern ammunition makes calibers that were once marginal much more effective. Or course, in many confrontations between citizens and aggressors, the aggressor doesn’t have a gun, and in a large percentage of those cases, the simple presence of the gun is effective for stopping the aggressor, whether that gun is a .500 or a .22.

Even if the citizen has to shoot the aggressor, many bad guys decide to stop simply because they’ve been shot. While I’ve never been shot, I have talked to people who have, and they tell me it’s not a pleasant experience. Of course, if the aggressor is pumped up with adrenalin, or drugs, or is experiencing a psychotic episode, he may not even feel a fatal shot that takes his life within seconds, and this type of aggressor is the only adversary the concealed carry citizen will face who’s affected by caliber choice.

This determined attacker has to be physically incapacitated to end the aggression, where the attacker cannot continue due to the level of his injuries. Fortunately, the percentage of determined attackers who persist even though seriously wounded is relatively small. A higher percentage of people simply stop the aggression when they realize they’ve been shot. Their reaction might come from the level of pain or fear of death and realization that continuing might end their life. This is considered a psychological stop.

Caliber and effectiveness of the round most likely have little to do with what’s required to produce a psychological stop. The sound of the gun associated with the pain and perhaps the presence of blood loss, all are likely to contribute to a cessation of aggression in a person predisposed to a psychological stop. In that scenario a .22 rimfire will probably work almost as well as a .44 Magnum.

Unfortunately, there are no in-depth studies that can give us exact information about what the optimum caliber for concealed carry might be. Even if there was, the constraints of each concealed carry citizen’s lifestyle would likely be more of an issue than caliber selection. The closest thing to a definitive study is entitled “An Alternate Look at Handgun Stopping Power” by Greg Ellifritz. Ellifritz compiled, over a 10-year period, statistics from 1,800 shootings with calibers beginning with .22 rimfire and .25 ACP and topping out with centerfire rifle and shotgun. The results were surprising in some ways and what you’d expect in others.

The criteria involved:
• The percentage of hits that were fatal.
• The average number of rounds before incapacitation.
• The percentage of people who weren’t incapacitated.
• The percentage of one-shot stops.
• The percentage of aggressors incapacitated by one shot.

The most surprising statistics involved the number of one-shot stops. While rifle and shotgun stops were more successful by an appreciable amount, the one-shot stop rates for handgun calibers from .25 to .44 Magnum were remarkably similar, only varying by a few percentage points. The average number of rounds required to incapacitate aggressors — two shots — was also remarkably similar. This might indicate that caliber makes little difference in the ability to stop aggressors. However, the percentage of people who weren’t incapacitated at all was much higher with the smaller calibers, but statistically almost the same for calibers from .38 Special on up to .44 Magnum.

Ellifritz concluded that, while it was true that the more powerful the round, the better the chance a determined aggressor could ultimately be stopped, the vast majority of aggressors give up when they know they’ve been shot. Click here to see the complete study.

The point of all this is that any reasonable caliber can stop an aggressor. At the same time, a determined aggressor can continue to fight, even if he’s mortally wounded by the largest handgun commercially produced, and even when hit in recommended target areas. It’s true that penetration is an important factor, as is the size of the wound channel, but these are issues that only count when the projectile is delivered to the right spot. The best advice is to carry the most powerful caliber and ammunition you — and the gun you commit to carry every day — can handle.