The Best Handgun Caliber for Your Concealed Carry Weapon?

The Best Handgun Caliber for Your Concealed Carry Weapon?

The age-old question that most of us shooters face is what is the best caliber handgun to carry concealed for self-defense purposes. As you would imagine, there are as many opinions about this as orifices in our teeth and many “experts” disagree on a specific caliber answer. The question itself and the answer are controversial. Some say the question should not be asked because there are just too many possibilities and variables and caliber is not a primary variable. They say a gun is just a tool and equipment and not as important as the shooter variables, so it depends for any given point in time and situation what is the optimal weapon and caliber. Others say there is not much difference (even statistically) among the basic calibers, so focus on shot placement and your skills, not the gun or caliber. Training and practice for accuracy are much more important than caliber and equipment, so why even address it they say. Others say there haven’t been any in-depth, longitudinal, scientific studies done to properly respond with a statistically valid and reliable answer. Bottom line is that we individually must address this for practical purposes and for our very survival. When deciding on what ammo and caliber to carry, consider your personal factors and skills, do your own ballistics research, and don’t believe the hype from salespeople and others. Ammo manufacturers do gel testing shoots and several are designed primarily to highlight only the manufacturer’s product and their goals, with most not allowing head-to-head comparisons among competing products. So what are the many considerations, the terminal ballistics, and the factors involved so we can decide for ourselves?

Remember, we want to “stop” the threat and use deadly force ONLY as a last resort to prevent imminent death or serious bodily harm. We should try to avoid deadly confrontations. But if we are in a life and death situation, we need to act quickly and appropriately. Exercise your brain! To begin with, here are some terms and factors we must understand to answer this caliber question for our self-defense.

Exercise Brain

  1. Bullet Penetration — the amount of body tissue (bones, muscles, organs, & fat) that a bullet passes through (the DEPTH) into tissue);
    1. Penetration is a key factor and many say it is the Number One factor for caliber decisions.
    2. Heavy grained and large bullets have more Penetration and create much tissue damage for optimal incapacitation to stop the bad guy/gal.
    3. After the infamous “Miami Shootout” of 1986, the FBI set a minimum Penetration requirement of 12 inches for their ammunition and this has become the industry standard.
  2. Permanent Cavity — the amount of empty space (the HOLE) left in the body behind the bullet. ALL bullets penetrate and leave behind a measurable Permanent Cavity, even the .22 LR;
    1. For self-defense purposes, a large Permanent Cavity with big HOLES enables more bleeding for quicker incapacitation.
  3. Temporary Cavity — the quick EXPANSION (WIDTH) of the Permanent Cavity stretching as the bullet’s Kinetic Energy is transferred to the surrounding tissue. ALL bullets create a Temporary Cavity, though it is difficult to measure;
    1. ALL bullets, even Hollowpoints and even the same brand from any manufacturer, expand differently with different Temporary Wound Cavities and diameters.
    2. Recognize “hydraulic shock” affects or the idea that tissue not actually touched by the bullet could still be damaged by the “energy dump” or “kinetic energy transfer” of the bullet’s velocity to the surrounding tissue.
    3. Usually, a bullet with much Expansion capability does not have as much Penetration and is generally preferred for concealed carry.
  4. Kinetic Energy (KE) — the energy of a bullet as it is expelled from the muzzle of a firearm’s barrel, due to its motion and acceleration. The bullet maintains its initial KE until its speed (velocity) changes, the further it travels. So, a bullet’s KE is greatly influenced by velocity and it decreases during flight. Generally, the heavier (grain) the bullet and the faster it moves (velocity), the higher its muzzle KE and the more damage it will do.
    1. KE is merely a number that indicates the potential ability of a moving bullet.
    2. The way a bullet actually Penetrates, Expands, and performs is most important and is indicated by its type, design, weight, energy, velocity, barrel length from which fired, distance, etc., as opposed to only its KE.
    3. In pistol calibers, there is usually not enough KE transferred to surrounding tissue (Expansion) to make any significant differences. So, Penetration and Permanent Wound Cavity (Hole) are two ways pistol calibers consistently damage tissue
  5. Fragmentation is the separation of the bullet into smaller chunks and pieces, which leave the Permanent Cavity and disperse in different directions. Fragmentation is dependent mainly on two factors; bullet design and velocity. Fragmenting bullets are designed to prevent over-Penetration & may not Penetrate adequately for self-defense concealed carry purposes, with Penetration being the priority;
  6. Personal knowledge and skills in the fundamentals & techniques of shooting for accuracy & safety;
    1. The author believes concealed carry shooters should focus on developing their fundamental shooting abilities and accuracy skills, rather than overly-focusing on their gun, calibers, and equipment. It is the shooter’s ability and skill at placing whatever caliber rounds (he/she chooses to carry in their handgun of choice) on target consistently that determines whether they will live or die in a deadly encounter.
  7. Gun Characteristics and Ammo Ballistics — cartridge type, gun type, bullet weight-grain, gun and ammo design, manufacturer, rated muzzle energy, rated muzzle velocity, barrel length, etc. Felt gun Recoil is important because it impacts accuracy and control and differs from small to large caliber rounds.

One-Shot Stops and “Knock-Down” Stopping Power

Many believe there is no such thing as a “man stopper” or a handgun caliber for concealed carry that is capable of a “one-shot stop.” Technically, there is no handgun cartridge with the capability to “knock down” a person. This is a hotly-debated subject and there must be recognition that some who have been hit may fall down for a variety of reasons. Some studies attribute falling down or “knock down” to solely psychological reasons. This is why some say that there is really no such a thing as “Stopping Power” of a cartridge or caliber to be considered. Bullets and cartridges of the same weight or grain may perform very differently. For example, in the chart below compare two .45 ACP rounds from the same manufacturer. A 230-grain Federal Full Metal Jacket (FMJ) round with a muzzle velocity of 890 ft/sec will Penetrate more than 31 inches of 10-percent gelatin. By contrast, a 230-grain Federal Hydra-Shok round with a muzzle velocity of 900 ft/sec will only penetrate about 15 inches. Both bullets have almost the same Kinetic Energy of 404-414 ft.lbs. but perform very differently. Also, the same round fired from two semi-auto pistols, one from a 3-inch barrel and one from a 4-inch barrel, will perform differently. The 4-inch round will travel at about 1255 ft/sec velocity, while the round fired from a 3-inch barrel will travel at about 1135 ft/sec velocity. The 3-inch barrel does not produce enough energy or velocity to make the bullet perform like it does when fired from the 4-inch barrel. The bullet Expands less, so it almost always Penetrates deeper.

I compiled the following chart comparing various caliber rounds from the same manufacturer (Federal), so you can see the different types, weights/grains, energies, and velocities to help you with your decision.

Handgun Caliber Chart
Handgun Caliber Chart

Stop the ThreatSTOP the Threat

It is generally recognized that the two primary methods to Stop a bad threat or engage a target are disrupting the central nervous system and causing massive blood loss. Just ask a deer hunter. The Stop is usually caused more by Penetration and the larger size of the hole or Permanent Cavity created. The total disruption of the central nervous system by destroying the lower half of the brainstem, the medulla oblongata, will cause a complete shutdown of the bad guy/gal and is the most difficult to attain. The medulla deals with involuntary functions, such as breathing, heart rate, and blood pressure. Accurately placing a shot at the base of the bad guy/gal’s brain that penetrates the skull and destroys the medulla is extremely difficult to do with a handgun cartridge. Massive blood loss is a slow process and the threat can still be dangerously active during it if not quickly stopped. For example,
the FBI Miami Shootout where good and bad guys were shot several times but continued the long battle.

The “average” human body is about 10″ thick from front to back. The FBI believes that for optimal performance in flesh, a bullet should penetrate between 12″ and 18″ in gelatin. That penetration distance ensures that the bullet will reach the vital organs even if it must first penetrate another body part (like an arm or leg) before entering the chest cavity. When penetration gets beyond 18″ in gelatin, there seems to be a greater chance for the bullet to pass through the body and strike someone else.

Penetration is something that is rarely discussed in self-defense conversations, but I believe it is a key element for proper cartridge design for carry. FBI research also indicates that the total depth of PENETRATION is the greatest single predictor of a bullet’s “stopping power”. But, if Penetration were the main and sole consideration for our caliber decision, we would all be carrying Full Metal Jacket (FMJ) rounds as the military does. The military issues those FMJ rounds because, under our interpretation of the Hague Convention, Hollowpoints (HP) are inhumane and contrary to the laws of war. While the U.S. never signed the Hague convention, we follow it strictly. However, our modern technology has made the HP bullet available and we should use it appropriately only as necessary in self-defense deadly encounters. It is designed to Expand and flatten out as it penetrates soft tissue, staying in one piece but forming a “mushroom” shape with a wider diameter (EXPANSION). This usually means less Penetration (DEPTH) than FMJ, but a bigger Permanent Wound Cavity (WIDTH-HOLE). If Penetration still meets the FBI’s required 12 inches, with a HP you have both to damage tissue. Recognize that there is not much KE remaining for a HP bullet to penetrate another person after the bullet is slowed by the expansion process.

The goal of concealed-carry shooters in self-defense ONLY AS A LAST RESORT against bad guys/gals is to maximize chances of stopping the threat by directly damaging vital organs with hits of 12 inches of Penetration along with the largest Permanent Wound Cavity. This maximizes chances of directly damaging something vital and perhaps saving your life. Don’t forget I believe that your ability to maintain consistent and accurate shot placement is far more important than the “stopping power” of any particular caliber.

Choosing Your Handgun Caliber

Accepting that accuracy is primarily about YOU and not your gun and caliber, a shooter wants the simplest, easiest gun to shoot well that he/she will carry and is comfortable with. So get the proper, professional training and practice shot placement… with whatever gun and caliber you use. Accept that there is no magical caliber or gun that will always stop the attacker. But, choose the largest caliber, the heaviest bullet, and gun with the optimal recoil and trigger control that you can handle to deliver accurate shots. The one you are going to carry with you and not leave at home in the safe is YOUR best choice. This can be a .380, 9mm, .40, or .45; so just practice. It is my opinion (and many disagree) that for carry the .380 ACP should be the minimum caliber you choose. But we have heard over the years that the 9mm bullet is better than the .380. Recognize that the bullets are very similar in size and weight with the significant difference being the velocity of the bullet.

If you have decided that your carry gun is one of the smaller, lighter calibers that is OK. Generally, this means that you need to understand that you must train that much more with a short sight radius, pocket pistol to be able to deliver multiple rounds to your opponent’s head to Stop the threat, than you would if you were carrying a 1911 in .45, a Glock in .40 caliber, or a Smith & Wesson 9mm and delivering two or three shots to the center mass or the chest. But, remember it depends on you primarily. What about carrying a .44 Magnum, .50AE, 10mm, etc? Since these guns require bigger and wider frames due to greater chamber pressure generated and larger cartridge size, they tend to be very hard to conceal and weigh more. Trying carrying one of them around for just a few days and see how it feels. Width is more important than length for a carry gun. These large guns, although they have slightly better overall stopping power than the 9mm, .45, and .40, do so at the expense of portability, recoil control, accuracy, and practical use. Again, it depends mostly on you and your fundamentals, shot placement skills, and practice. Another consideration now is cost and availability of ammo. Can you afford to practice regularly with this caliber? Larger caliber ammunition is generally more expensive than smaller caliber ammunition. Also consider the availability and how easy it is to locate boxes of cartridges in that caliber. GENERALLY, calibers smaller than .38 Special/9mm do not penetrate as well to reach truly vital structures deep within the body. Once the threshold of adequate Penetration is reached, bigger caliber bullets seem to offer the advantages of larger diameter wounds, more profuse bleeding, and being more likely to break or glance off bones. Generally, the handguns literature overall doesn’t report much statistical difference in “stopping power” between 9mm and .45 ACP cartridges as along as quality HP ammo is used.

Consider carrying +P loads for self-defense for any firearms that are rated for that cartridge. The +P is a cross between a standard cartridge load and a magnum load. It gives increased projectile velocity, better cutting power, and penetration. CAUTION: Be sure to CHECK that your firearm is rated for a +P load before you use it in that firearm. Also recognize that if a court battle emerges, the +P load might work against you for self-defense and be considered too aggressive and an “overkill.” Choose your caliber wisely. Check the handgun itself, especially revolvers, and look for the cartridge rating. Check your owner’s manual for +P rating for your firearms. Generally, older firearms are not rated for +P ammunition. Also, +P+ ammunition is available. I do not recommend it for carry. Your call. This ammunition is generally used for pistol-caliber carbines, specifically machine guns. I strongly recommend you do NOT use +P+ ammunition in your handgun unless you are certain that the gun is rated specifically for +P+ ammunition. Be certain your firearm is rated for whatever ammunition you use.

Also, I do NOT recommend hand loading self-defense carry ammunition. There are liability concerns should you have to use the ammunition in self-defense. Modern manufacturing techniques are so good that buying ammunition from a respected manufacturer with high quality-control and consistent standards is a much better choice. The handgun you spend so much money on to buy and train with for concealed carry is absolutely useless without effective ammunition. Spend a few dollars more and get the best ammunition to keep yourself and the people you love safe.

I mostly carry a 9mm and I know the round leaves the muzzle at 1200 feet per second and has a 124-grain +P bullet. For me, the increased bullet weight and muzzle velocity make the 9mm effective in personal defense. Recent studies conclude that among the various calibers (9mm, .40, and .45) there is not much difference in stopping power. Spaulding did a 2012 study to support this, as did Ellifritz. The statistics showed that the three calibers were very close in the number of rounds needed for incapacitation, with all three requiring almost 3 shots. Spaulding also concluded that the depths of penetration from one of these three calibers to another were very similar. He believes that while the .45 is a bigger bullet than the 9mm and has more potential to do more damage, there is more felt recoil in the .45 which affects accuracy and target hits. It was summarized that there is only about 15-18% more damage (as measured in small MMS) for the .45 over the 9mm and .40 calibers, which is not enough difference to make up for its poor shot placement. Recognize that personal skill is important here. Ellifritz’s study looked at over 1800 shootings and concluded that the average number of rounds for incapacitation was 2.08 for the .45; 2.36 for the .40; and 2.45 for the 9mm. All very close. Again, your decision.


To me, a gun and ammo are tools and equipment and not as important as the shooter’s ability to be consistently ACCURATE with whatever gun or round is chosen. Penetration and the Permanent wound Cavity or Hole made are very important factors in incapacitation. Both Penetration and Expansion are critical factors for self-defense and for carry purposes. For effectiveness, there should be a minimum Penetration of 12 inches for the ammunition chosen. For self-defense purposes, a large Permanent Cavity with big Holes enables more bleeding for quicker incapacitation. ALL bullets, even Hollowpoints and even the same brand from any manufacturer, Expand differently with different Temporary wound Cavities. Usually, a bullet with much Expansion capability does not have as much Penetration and is generally preferred for concealed carry, but be aware of legal liability and court interpretations. Fragmenting bullets are designed to prevent over-Penetration and may not Penetrate adequately for self-defense, concealed carry purposes. Bullets and cartridges of the same weight or grain may perform very differently. Generally, bullets that expand less almost always Penetrate deeper. Your ability to maintain consistent and accurate shot placement is far more important than the “stopping power” of any particular caliber. Handgun studies overall do not report a much statistical difference in “stopping power” between 9mm, .40, and .45 ACP cartridges, as long as quality HP ammo is used. Generally, I recommend the 9mm as the best all-around caliber for concealed carry licensees, but with HP ammo, +P load, and 124 grain weight. Again, your abilities, skills, accuracy and shot placement are more important than caliber chosen. There could be a legal liability court concern in the event of a carry self-defense situation and the ammo and caliber you choose. Consider the many variables presented above to make YOUR caliber decision logically and rationally for the sake of your life.

Continued Success!

© 2013 Col Benjamin Findley. All Rights Reserved. This article may not be reprinted or reproduced in whole or in part by mechanical means, photocopying, electronic reproduction, scanning, or any other means without prior written permission. For copyright information, contact Col Ben Findley at [email protected].