9mm best defensive ammunition

0332 – 9mm, The Best Caliber for Concealed Carry?

40 S&W 45 and 9mm

.40 Smith and Wesson fits firmly in the middle between 45 ACP and 9mm

When it comes to topics in self-defense handguns, there are few debates that are hotter than what caliber you should count on in your concealed carry handgun.  There are those that carry a .45ACP because there is no .46 and those that prefer the .380 because of its diminutive size and ease of concealment. Of course, there’s also every opinion in between.  When we take a logical look at what caliber we should carry for defensive purposes we can start to get to the bottom of this complex question.

Today let’s talk about caliber for your concealed carry handgun and your home defense handguns.

What is the Best Caliber for Concealed Carry?

It helps us to understand how it is that ammunition works to physiologically stop our threat.
It really boils down to two things bullets need to do:
  1. The bullets need to penetrate deep enough into the body to get to something the body finds important to survival
  2. The bullets need to do damage when they get to those important parts.
Many people fail to consider the multidimensional approach we need to take to achieve these two goals as efficiently as possible and of course because of the stakes involved we must do the work to select the best caliber for concealed carry.
Much of the debate that surrounds caliber selection is illogical and frustrating to me. People base their choices on a single attribute of ammunition or maybe worse what their uncle who was in the war thinks or what their local police department carries.  While your favorite uncle might have some valid experience from combat and your local PD certainly should have valid reasons for the round selection they have made, we must understand that our context as a concealed carry holder is different than the military and law enforcement aspect would lead us to believe.
Unlike the military or the police, The law abiding citizen typically carries a firearm concealed. This means that a balance must be struck between the ability to conceal and recoil management of the handgun and we talked about this in detail in episode 331.
9mm removed from pig carcassIn addition, when it comes to law-enforcement it must be taken into consideration that the context of police work is different than that of concealed carry.  For example, LE officers have a much higher likelihood for the need to shoot through intermediate barriers. Although certainly a possibility, this is not typical for those involved in concealed carry.  Shooting through intermediate barriers can have a profound effect on terminal ballistics.  For this reason we can’t simply assume that what our local PD carries is what we should carry.
The military comparison doesn’t work well either. Those that carry handgun in the military are typically required to carry full metal jacket ammunition.  On the contrary, if you carry concealed, you should be looking for modern bonded hollow point bullets. The terminal performance of full metal jacket compared to modern bonded hollow points is like night and day.   Expansion is the big difference.  This means that military personnel may have some very valid reasons for carrying a caliber your average citizen might want to avoid.  Remember when selecting the best concealed carry ammunition bonded hollow points are better than full metal jacketed rounds regardless of caliber.
Instead of looking at a single area of performance the savvy defensive shooter will seek to balance out a group of characteristics to achieve the most efficient results.
The information I am presenting today is similar in many ways to the concepts that are being taught by Defensive Firearms Coaches around the country.  You can find these instructors by taking a look at our Ohio Concealed Carry Course or a Critical Defensive Handgun course.

So let’s get down to the meat of it.  Why is 9mm a better caliber choice for a defensive or concealed carry handgun than other common defensive calibers such as .40 Smith & Wesson or .45ACP.

Terminal Performance

The first important point deals with the terminal performance of modern 9mm, bonded, hollow point ammunition.

When we look at the terminal performance of handgun calibers from .38 special through .45 ACP and limit the results to modern bonded hollow points, we notice something very interesting.
The physical damage caused by a single bullet of any caliber in that range has a negligible difference.  We don’t see a massive difference between 38 special 9mm, .40 S&W or .45ACP wound channel.  Now, don’t think for a second that I’m arguing that there isn’t a difference between a 9mm wound channel and a .45ACP wound channel.  There is.  What I am arguing is that in the majority of circumstances that difference is virtually irrelevant.  A 9mm makes a big enough hole that goes deep enough to reliably stop a threat.
If you were to ask the doctor treating a gunshot victim what they were shot with the answer would probably be something like “a handgun.” If you were to press for more details you probably wouldn’t get much additional information until the projectile was measured with a set of calipers.
Certainly there are some .45 ACP wound channels that are massive compared to 9mm channels but there are also massive 9mm wound channels and less devastating .45 wounds.  When we compare modern bonded hollow points the damage done is more likely a function of where the individual was shot and other factors such as bullet path, clothing worn and intermediate barriers than the caliber of the round itself.
We have to understand that when we level the playing field with modern bonded hollow points and all other things kept equal, most handgun calibers do about the same amount of medical damage as most other handgun calibers.  Once we get to a cartridge larger than the .380, the bullets are getting deep enough and expanding big enough to do the kind of damage we need to do to stop our threat.
When it comes to the ability of a single bullet to cause damage there is little difference when we compare 9mm vs .40 S&W, 9mm vs .45ACP or .40 S&W vs .45 ACP.
So at this point it might seem to you that I made a case that all handgun calibers are about equal.  If terminal ballistics were the only factor maybe that would be so, however it’s not.  Let’s look at the rest of the picture and why I believe that the 9mm is the best defensive caliber.

Ammunition Capacity

9 mm is smaller than the other acceptable Defensive cartridges.  Size has several advantages to it. First of all because the diameter of the bullet is smaller or larger number of cartridges will fit into the magazine then in other calibers.  If we take into account clocks full-sized handguns and make a comparison we know that the GLOCK 21 carries 13 .45 ACP cartridges in this magazine the GLOCK 22 carries 15 .40 S&W cartridges. When we compare that to the 9mm the difference is significant.  A GLOCK 17 in 9mm carries 17 9mm Luger cartridges.
So simply put 9mm handguns can either be a smaller package, a higher capacity that the same sized guns in .40 or .45.


Even in today’s world of inflated ammunition prices 9mm is less expensive than 40 S&W, .45 ACP or other defensive handgun cartridges.  If we only bought ammunition once the cost issue may not play as much of a factor however I encourage you to train with your home defense or concealed carry handgun.  Less expensive ammunition means more training.  In addition, from time to time you should train with your concealed carry ammunition.  The lower the cost of ammunition the more training you can afford to do with your defensive handgun. The more training you do with your handgun the more efficiently you will operate it.
Again, the advantage goes to the 9mm over .45 or .40 due to its lower cost.

Recoil Management

The 9mm cartridge tends to have very manageable recoil especially in handguns that are compact or larger.  When it comes to using a handgun for defensive purposes, recoil management is an important attribute.  We are looking for rapid follow up shots as we expect that it is going to take more than a single shot to stop our attacker.  This means that the ability to control the recoil of the 9mm is a great aid in getting the gun to settle back onto the threat quickly so that we can take rapid follow up shots when required.
Because 9mm has less felt recoil than .40 or .45, 9mm is easier and faster to shoot.

Wounding Capacity

Wounding Capacity is really the deciding factor when it comes to caliber choice for concealed carry and home defense.  It is the deciding factor because it logically ties together the factors that most people rely on independently to justify their choice.  We cannot rely on a single attribute of our self-defense ammunition.  Instead, we have to look at the whole picture.  That whole picture is wounding capacity.  Let’s look at the factors that determine wounding capacity and what they mean when they work together.
  1. Single wound channels from modern bonded hollow points from .38 special through .45 tend to have a negligible difference in the physical damage they cause.
  2. The higher ammunition capacity of the 9mm allows for more rounds to be carried in the gun.
  3. The lower cost of 9mm allows for more training and therefore improved recoil management.
  4. The recoil management of 9mm allows more rounds to be fired with the required precision in a given amount of time.
These three factors give us the whole picture which is that the 9mm allows us to put a larger number of rounds on target in a shorter period of time compared to other calibers like the .40 S&W or .45ACP.  Since all the holes have about the same value as far as tissue damage goes, more slightly smaller holes is better than less slightly larger holes.  Since the 9mm can cause more holes in a given amount of time it has a greater likelihood of achieving the physiological effect on our threat that we need to stop a violent threat by driving deep enough to hit something important and doing damage when it gets there.
The concept is fairly simple.  The slightly bigger hole that the .45 or .40 makes over the 9mm has little effect on the outcome, but the fact that 9mm can make more holes does have a significant effect.
The wounding capacity of the 9mm allows us to make more holes.  Make sure that you take wounding capacity into account as you search for the best caliber for concealed carry.

7 replies
  1. David from Alabama
    David from Alabama says:

    Paul, I really enjoy your thoughtful podcasts. In this episode, you make the statement something like, “we know you can put more shots on target in a given amount of time with the 9mm.” Do you have some objective measure of how much faster that you can share? From my own experiments using a shot timer and 8″ target @ 7yds, my splits with a 9mm are about .18 sec while my .40 cal splits are about .23 sec for Glock pistols. Are these results comparable with your experience? I haven’t tried the 10mm versus the .45 yet or the 1911 versus the G21. Do you have any data for the larger calipers?

    • PaulCarlson
      PaulCarlson says:

      Dave – Your numbers are pretty much where I would expect them to be. I don’t have any objective data for those larger calibers, but I am heading to the range next week on Tuesday with the specific purpose of getting that data for 5 shot strings with various calibers and we will be shooting some video too!

  2. sturm r ruger
    sturm r ruger says:

    9mm all the way. 45 guys talk their crap cuz they prob got a small penis and try n make up for it. Ya want a big gun, get a 10mm, they bad ass. 9mm n 45 n 40 cal r all bout the same, so go with 9 they hold more and they will still blow a suckaz head clean off. Dont forget tho, whatever ya get make sure ya show everyone n let em kno… if they mess wit ya, you will bust a cap in their sorry asses. Peace.

  3. Paul
    Paul says:

    I am in Oklahoma, we have open carry here. So concealment is not the issue, nor have to worry about the size/caliber of the weapon. So my weapon of choice is a .45 ACP, Para Black Ops 14-45. So that is 14 in mag 1 in chamber.

  4. Mark Ollendale
    Mark Ollendale says:

    You’re certainly not alone – there are a lot of shooters who feel you’re silly to make the case for anything other than 9mm when it comes to best handgun caliber. Personally, I carry a PPS chambered in 9mm and love it. That said, I do appreciate .40 and .45 as well. Here’s a cool look at some of the more popular reasons why 9mm might be the best to carry if you’re interested: http://www.ammoforsale.com/9mm-ammo-for-sale#best

  5. best caliber for self defense
    best caliber for self defense says:

    you are right man well i know all folks in united states using 9mm caliber guns. 9mm is the best handgun of 21st century. and when it comes to .45 , .40 .385 its relatively cheap and more effective. 9mm is also called the people gun. Mostly glock guns are made in 9mm caliber due to its demand and supply. But when it comest to .45 the 9mm is still an effective and people choice

  6. what is the best caliber for self defense
    what is the best caliber for self defense says:

    I really enjoy taking a look at others to see how they dress when they are wearing their weapons. It challenges me to notice small changes in the way that people move and how they interact while carrying. A lot of folks that I know that concealed carry are pretty obvious about it, at least from my view. They wear huge shirts, and while they may not print through them, it’s still hard to imagine that they’d ever put on a shirt that large without having something to hide. Also, while I may not have the budget to be able to tailor all of my suits to my weapon (as someones has done above), I do make sure that my casual attire is appropriate. I enjoy having a smaller weapon (Kahr PM9) so that I can carry and wear my normal tee shirts and an IWB holster, and I don’t print much, if at all. I’ve also taken to clipping my cell phone on my pocket on the opposite side. That evens out the appearance of my body, and it also distracts the eyes of passersby so that the phone “grabs” someone’s eye more easily than the small inconsistency in my waist. Distraction is a great technique, and if there’s a subtle way to employ distraction, I highly recommend doing so. This can be done for almost all force tools, in a multitude of ways.


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