9mm vs .45 — which really IS better?

Yes, I’m diving into the “9mm vs .45” war.  No, I don’t care that you have a preference.  (I don’t care in that it doesn’t matter to me, though obviously it should matter to you.)  Yes, I realize that many people will immediately hate me no matter what I’m going to say next.

Before I jump in, though, here’s my question to you:  Do you know what current research says about ballistic effectiveness when comparing modern self-defense rounds between 9mm, .40S&W, and .45ACP?

If the answer is “No” then your opinion is useless, whether it happens to be right or wrong.  You see, here’s the deal:  Your ignorant opinion (ignorance:  lack of knowledge, which is not the same as stupidity) is simply not as valid as someone else’s knowledgeable opinion.  This doesn’t mean that you might not be right, and the other person can’t be wrong—but it DOES mean that if you start by saying “Well, I don’t know much about it, but I think…” —-then the rest of your sentence really should be— “….that I should shut up and learn about the subject before I express my opinion.”  If you happen to be right in your opinion, it is purely due to luck, since you have already admitted you don’t know what you are talking about.

Do you have a caliber preference in terms of self-defense round?  Probably.  Is that preference based on “feel,” personal expectations, personal experience, opinions heard on the internet, opinions heard from friends, or wide-scale research data?

Because while you are welcome to go with whatever your preference is, the only reason list above that is valid for reliable results is the last one—wide-scale research data.  How it “feels” doesn’t tell you anything.  Personal expectations based on what?   Personal experience—well, once you’ve shot 1000 people with varying rounds for comparison purposes, get back to me.  Opinions heard on the internet or from friends?  Please.  I’ve heard people advocating disassembling a handgun one-handed and putting the parts in a bag on the dashboard while coming to a stop on the highway when pulled over by the state patrol in order to make the LEO more comfortable with the firearm.

(No, I’m not kidding about that.  I wish I was.)

So why should you listen to my opinion?  Because I’m right?  How about because I’m telling you not to take my opinion as gospel, and instead telling you to look at what the research says, and what it means.



I realize that is actually considered sacrilege to the “.45acp is God’s Own Round” crowd and the “9mm capacity makes all the difference” crowd and the “.40 is the best of both worlds” crowd.  (Not to mention what the 10mm Manly Man are like on this topic.)  And yet—opinions based on lack of fact mean nothing.

Oh, good lord, I forgot the .357Sig fanatics.  Yeah, them too.


I’m bringing this up because I have a friend who carries a Glock 30 in .45acp all the time.   He likes to shoot IDPA matches, but realizes that particular gun is non-optimal for the IDPA game for all that IDPA touts itself as being for “real concealed carry” training.  In SSP or CDP he is at a “compact gun” disadvantage, and in SSP he is at a serious recoil disadvantage.

He asked me about switching to a 9mm for IDPA, and I asked him (since I knew he carried his G30) if he wanted IDPA to be for trigger time with his carry gun, or instead wanted to work on winning matches.  After all, while trigger time is always good, the grip on a full-size 9mm Glock is different from the grip on a G30, and if he wanted to work with both, it was going to take even more practice.  So, did he want to mazimize his SD practice and also play at IDPA, or did he want to practice with two guns, work on SD, and work on IDPA at the same time?  He decided that was really the question, and started thinking about it.

(I realize that at this time, the people who carry 5 different guns and rotate them out weekly or have the “you should be able to handle EVERY gun!” attitude will be wondering why this is a problem.  For you folks, never mind.)

Back to what my friend was thinking about:  When I thought about it, I really wondered if that really was the right question.  What if, instead, the real question is:  are you completely wedded to the idea of a .45acp for self-defense?

You know what current research says about modern self-defense rounds in 9mm, .40S&W, and .45ACP?  It says that 1) all are marginal in effectiveness, 2) reliable physiological stops only occur due to disruption of the central nervous system (CNS), 3) those calibers work equally well (or rather, equally badly) for shots placed in the CNS, and 4) all calibers (including .22) work equally well for psychological stops.  Oh:  5) Heavier bullets (in pistols) work slightly better to defeat intermediate barriers, if your lifestyle happens to be such that you often have to shoot through doors and windshields.

(How many .45/.40 folks just said, “Well yeah, see, mine is better” I wonder?)

How often DO you want to be able to shoot through intermediate barriers?  (Unless you have a job that potentially requires it, of course.)  Don’t people who think about normal citizen self-defense usually worry about the exact opposite?

So here’s the thing:  unless you have a job that requires you to have slightly better than pretty bad barrier penetration, there is no effective difference between 9mm, .40S&W, and .45ACP.  For physiological stops, they are all very bad unless you get a precise CNS hit, whereupon they all work equally well.  For psychological stops, they all work as equally well as a .22 LR out of a Beretta Bobcat.

So truthfully, my suggestion to my friend?  Think about carrying a G17 or a G19 instead of that G30, and use a G17 or a G34 in competition.  The grip, trigger, and recoil will all be similar, you’ll have more rounds for self-defense (without giving up much of anything in effectiveness), and you’ll be more competitive in IDPA all at the same time.

That isn’t to say that everyone should carry a 9mm.  You should carry whatever you like!  This merely is my solution to my friend’s problem, and YOU may not have this problem.  You may just like the feel of a 1911 in .45acp better plus you think JMB was the last True Prophet.  Or you may like the .40 because muzzle blast, recoil, AND capacity should all be maximized simultaneously.  Or maybe you like 9mm because…..well, there’s probably a reason out there somewhere to like 9mm.

Pick what you like.  But 1) don’t base your decision on some supposed “advantage” to one caliber in terms of effectiveness—there isn’t one, and 2) don’t let your personal preference get in the way of making the most logical choice for all the reasons you might need a gun.

And quit telling me that your caliber is better than the others for random nonsense reasons that have no basis in reality.


(No, I haven’t forgotten about the “How to Learn To Shoot” series—part IIA will be coming relatively soon.)

3 thoughts on “9mm vs .45 — which really IS better?

  1. Of course, seeing how you’re using facts and data, no one who needs this advice will actually pay attention to it. Lord knows I can rarely get any of the diehard “I don’t shoot anything that doesn’t start with a 4” people to listen.

    As for your friend, since he can make the sights and trigger on his G30 match the sights and trigger on a G34, just getting the G34 is probably a more cost effective option. I have a G34, G35, and a G21. They aren’t that different.


  2. Does anyone, ANYONE really believe that there is “no” psychological difference between a .22LR and a hot .357M or .45+P hit? Anybody at all? Really? **shaking my head**

    Would anyone, ANYONE, really, bypass a .45 with 8 rounds of +P in it to pick up a 9mm with 8 rounds of +P in it, if they KNEW that they were ten seconds away from a handgun fight to the death? Anybody at all? Really? **shaking my head**

    Depending on the situation, level of activity, clothing worn, weather, etc. , I may choose CCW with anything from an Airweight J-frame .38 to a compact 9mm to a full-size .45. I am not stuck on any particular cartridge or pistol, BUT, each does have advantages. There ARE effective differences, especially now with some (ignorant AND stupid laws) limiting magazine capacity or NJ’s forbidding ALL hollow points(!). Just sayin’, my friend. Shoot straight, fast and hard.


    • So what you are saying is that all the current research is wrong?

      Or perhaps we have a definition problem. You say “does anyone, ANYONE really believe that there is “no” psychological difference between a .22LR and a hot .357M or .45+P hit?” —and the answer is, “depends on what you mean.”

      Research shows really clearly that there is no difference in the effectiveness of psychological stops between any particular caliber. This is not the same thing as saying there is no difference period. Merely that there is no difference in the effectiveness in terms of causing a psychological stop.

      So yes, many people believe that there is no difference in effectiveness in that respect. After all, the point of a psych stop is that the person could have continued, but didn’t do so even though they were physiologically capable of doing so.

      As for who would bypass a .45 with 8 round of +P in it to pick up a 9mm with 8 round of +P in it—-quite a few people. Simply, 9mm is easier to shoot accurately and quickly. Considering that there is no difference in effectiveness between the two calibers, AND it is easier to shoot accurately and quickly, plus to get a physiological stop you need hits to the CNS quickly–LOTS of people would probably choose the 9mm if they were used to it and normally shot it.

      “There ARE effective differences, especially now with some (ignorant AND stupid laws) limiting magazine capacity or NJ’s forbidding ALL hollow points(!). ”

      Other than the last point (no hollow points), what effective differences are there? Meaning, what differences in effectiveness are there? (Sure, a .357M is a lot louder, and a lot faster than a 9mm. So, more kinetic energy, and more momentum than a 9mm. But that doesn’t seem to actually correspond to effectiveness differences.) Can you point out any research showing any? (My post specified modern hollowpoint ammunition. So obviously, that doesn’t hold for NJ’s stupid laws.)

      You say that each has its advantages, from 9m to .45. In terms of actual effectiveness, what advantage does a .45 have over a 9mm? (I note: I’m not saying people shouldn’t carry a .45. My point is that people can carry whatever they like, because current research is saying that they are all good, as long as you can be fast and accurate with them.)


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