Tuesday topic: Defensive pistol magazine capacity

I saw a post from Jim Wilson this morning on the Bookface, and I had to slow-clap for the absolute perfection of it:

If you can’t see the FB embed for some reason, it says this: “High-capacity pistol magazines are only important if you plan to miss a lot. And you can’t miss fast enough to win.” You can see now why I appreciated it, because if you accept the general premise of most online communication is to spark “engagement” that post is going to work really well for that. Well played.

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But let’s talk about the actual content of that post for a second. Many of us, myself included, carry wee little guns like a j-frame or an M&P Shield simply because we find it either too inconvenient (in my case) or too difficult (in other cases) to carry a proper full size service pistol. To further examine the issue of defensive pistol capacity, we have to look at probabilities. Here is a simple list, in order from most likely to least likely of defensive situations the average person (not a cop) is likely to encounter.

  1. Will never need to draw their gun in anger – most likely
  2. Will need to draw their gun to defend themselves from a single assailant, no shots fired.
  3. Needs to draw their gun to defend themselves from a single assailant, shots fired.
  4. Needs to defend themselves against multiple assailants.
  5. Needs to defend against multiple, determined, armed assailants in a “proper” gunfight – least likely.

I’ll take a moment of rare honesty: the vast majority of Americans will get by simply by playing the averages and will likely live their entire lives in peace and not need a gun. That’s awesome.

But here’s where it gets complicated. Because if you remove the tools of self-defense from the above probabilities, the odds that any of those situations other than number 1 end up going well for you becomes nearly zip. So we carry our guns, not because we’re paranoid, but for the same reason we keep fire extinguishers in our homes. I generally hate the cutesy phrase “better to have it and not need it” but it is actually applicable. If someone never draws their gun in self-defense their whole life, they have an undefeated gunfight record, the best way possible.

Now that we’ve established why we should in fact be carrying a gun, let’s get back to the question of capacity. Caleb’s Rules of Gunfighting that I just made up for this post state:

  1. Have a gun
  2. Having a gun in a proper service caliber is better than a gun in a mouse caliber
  3. There is no effective difference in terminal ballistics between modern service caliber loadings with proper, modern JHP
  4. 9mm is easier to shoot than .40 or .45
  5. So carry a 9, dumbass

I don’t particularly plan to miss a lot if I ever do need to use a gun in self defense. In fact, I don’t plan on missing a lot when I shoot matches. But I still like having extra bullets in the gun, because sometimes things go pear shaped. If you’re in one of those situations where there are multiple attackers, or maybe just one guy that doesn’t realize he should die immediately because you shot him with a .45, having more bullets is never a bad thing. It gives you options. I like having options.

Once you get past the 1970s stopping power arguments and accept that we live in a magical age of pistol bullet equality, it’s no longer a question of capacity but rather a question of “what can you get the most hits with, the fastest.” The answer is almost universally a modern, polymer, service in 9mm. Let me know your thoughts in the comments.


  1. LMAO @ “…or maybe just one guy that doesn’t realize he should die immediately because you shot him with a .45…”

    As friends of mine like to jest, “But if you shoot them with a .45 it will hurt more!”

    Thank you for your clear-headed, rational, and non-emotional analysis.

  2. It’s all compromise made by weighing the odds. For me it’s a high quality single column 9mm. Sometimes but less often it’s a J frame Airweight.

    If God told people were going to break down the door and try to kill 60 seconds from now and it was already too late to leave, it would be a 5.56 carbine or 12 gauge. If it had to be a 9mm pistol I’d rather have a full size 16 shot than a smaller one.

    And while I agree it’s pretty much the magic age of bullet equality and 9X19 is an excellent round, forgive me ’cause I’d still rather have a big 10mm in my hand in that situation.

  3. Last time I was at Gunsite, my friend Dave Starin remarked, “The only time you can have too much ammo is when you’re drowning or on fire.”

    That said, I’m perfectly content with a good single-stack 9mm like a Shield.

    1. Mike,

      I’m going to steal that one form you.

      “The only time you can have too much ammo is when you’re drowning or on fire.”

    1. 9mm is made in many countries do a search and see.I suggest google or bing for best results the 9mm is a very popular round hope this helps.

  4. My mantra regarding defense handgun caliber/capacity:

    1) Select the most powerful/effective self defense ammunition you can accurately and repeatably put on target.

    2) Select the largest and most ergonomic platform to to utilize that caliber that you are dedicated to carrying everyday (or for a given situation if multiple options are available).


    The more energy transferred to your target increases the probability of incapacitating said target. Multiple hits to a target also increases that probability. So logically you want to hit your target as many times as possible, as quickly as possible, and with as much force as possible. My order of precedence is: # of hits > power of hits. So If you’re inexperienced or not strong enough to put multiple, quick hits on a target with a service-grade caliber, then take a step down. Maybe your ceiling is 380 ACP. Maybe 22 WMR. Maybe 22 LR. Whatever is greatest and meets the criteria should be your selection.

    Once you’ve determined the caliber, then find the best platform to utilize it. Ideally, you want more firepower than your opponent, and because your opponent is unknown you want to maximize your capacity. The obvious downside to more immediately available ammunition (i.e., capacity of weapon w/o reload) is more size and weight of your platform. Each individual should define their limitations (e.g., body type, clothing, occupation, etc) and choose the largest and most comfortable platform that doesn’t exceed those limitations.

    Personally putting into practice:

    Regarding #1. I’ve an experienced shooter who shoots a couple thousands rounds a year. While there are more powerful cartridges than 9mm Luger, they aren’t necessarily more effective for self defense in my considerations, so I selected Hornady Critical Defense in 9mm.

    Regarding #2. I’m a full bodied, average man (not fat, not thin). I work in an office where open carry isn’t allowed, and I sit at a computer the majority of the day. I dress “business casual” the majority of the week. With these limitations I selected the Beretta Nano as my EDC. A small, single stack, polymer 9mm pistol (other options were M&P Shield, Kahr P/CM9). I carry the Nano under my shirt in a belly band/shoulder holster, because IWB holsters are uncomfortable to wear sitting down 8 hours a day for me.

    1. I agree completely Seth. In addition, I know a LEO who talked me from the critical defense into the critical duty as they are designed to go through windshield glass and our local LEOs prefer them. You never know when you might need that extra benefit for only a couple $$ more.

      1. Critical duty is designed for full size guns, where defense is better suited for small ones, shooting the bull does a good analysis of the differences and why they are designed for different applications.

    2. “IWB holsters are uncomfortable to wear sitting down 8 hours a day for me.”

      In my experience, this discomfort largely goes away once you break in your belt. I’ve been carrying full-size semi-auto pistols for several years at this point, and most of the time I carry IWB (generally with a Crossbreed ST). When I started out, it was highly uncomfortable, because my belt put uneven pressure on the holster/gun. As the belt broke in, that discomfort disappeared entirely.

      My advice is that you get a good belt (double-layer leather, preferably 1.5″, with nothing additional to stiffen it), and carry IWB with it as often as you can. Start off by carrying that way in the evenings after you get home from work; After a few weeks of that, you will break in the belt and it will become much more comfortable.

  5. I like reading your articles… don’t take this the wrong way. Maybe your first bullet bullet could be worded differently. Here’s my point; the cop asks you “why did you pull your licenced concealed weapon and shoot this guy?” Your answer should not be “I was angry”. Keep up the good work : )

  6. “or maybe just one guy that doesn’t realize he should die immediately because you shot him with a .45, having more bullets is never a bad thing. ”

    Obviously, this is why you need to carry 10mm, as they hit like a train driven by a lightningbolt from Zeus and can take down a charging bull whale with one shot.

  7. There are numerous examples of individuals being stopped with a .22 or a .25. There are also numerous examples of individuals being hit multiple times with .40/.44/.45 etc. bullets and it doesn’t phase them–at least not for a while. Therefore, hit them where it counts and keep hitting them until they stop! There is no such thing as bringing too much ammo to a gunfight. Also remember, the first person to stop shooting in a gunfight is most likely going to be the loser!! You don’t want to be the first one to stop shooting because you ran out of ammo.

  8. The 1911 45 caliber weapon was made for one reason, to kill a human. 9mm is light, easy to shoot and it is what I carry but I love the 1911 45. In the end, I agree with you

  9. Let’s throw in a bit of economics analysis too. Not dollars and cents, but the economic analysis of how and why people do things, which includes dollars and cents. Nine mm is cheaper to shoot, so, on balance, people will do more of it in training, thus making it more likely that they CAN hit. Nine mm is also eyes, ears, and hands, so people will do more training and will be less likely to flinch when they have to pull the trigger. Again, this makes it more likely that they will hit the target when they really have to. Finally, let’s look at the economics of the bad guy. If the good guy is shooting at you and missing, but the bullets keep comming, then you are even more motivated to get moving. Yet another score for the 9mm with its increased magazine capacity. I know that the same can be said of the mouse calibers, but you do want the round to work if it hits, so let’s not go there.

  10. Caleb’s Rules never mention capacity, but he mentions it after.

    What if capacity is capped by law? Does that change any opinions? If we compare Glock’s lineup, Caleb is saying he’d rather have 17 rounds of 9mm than 13 rounds of .45ACP. What about 10 rounds of 9mm compared with 10 rounds of .45? Would any of you that choose 9mm for capacity reasons choose a bigger caliber if you were capacity-limited?

    1. I’d rather have 10 rounds of 9mm because it’s cheaper to train with and easier to shoot well.

  11. 9 mm will get the job done and then some in a short distance defense situation. It’s my everyday gun and is perfect for carry. If I am hunting or hiking near the Mexican border (joke) I would prefer a .45 with a few extra clips

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