Ballistics by the inch

Handgun caliber and lethality.

This post is NOT about gun control, even though the article which it references specifically is. I don’t want to get into that discussion here, and will delete any comments which attempt to discuss it.

Rather, I want to look at the article in order to better understand ‘real world’ handgun effectiveness, in terms of the article’s conclusions. Specifically, as relates to the correlation between handgun power (what they call ‘caliber’) and lethality.

First, I want to note that the article assumes that there is a direct relationship between caliber and power, but the terminology used to distinguish between small, medium, and large caliber firearms is imprecise and potentially misleading. Here are the classifications from the beginning of the article:

These 367 cases were divided into 3 groups by caliber: small (.22, .25, and .32), medium (.38, .380, and 9 mm), or large (.357 magnum, .40, .44 magnum, .45, 10 mm, and 7.62 × 39 mm).

And then again later:

In all analyses, caliber was coded as either small (.22, .25, and .32), medium (.38, .380, and 9 mm), or large (.357 magnum, .40, .44 magnum, .45, 10 mm, and 7.62 × 39 mm).

OK, obviously, what they actually mean are cartridges, not calibers. That’s because while there is a real difference in average power between .38 Special, .380 ACP, 9mm, and .357 Magnum cartridges, all four are nominally the same caliber (.355 – .357). The case dimensions, and the amount/type of gunpowder in it, makes a very big difference in the amount of power (muzzle energy) generated.

So suppose that what they actually mean is that the amount of power generated by a given cartridge correlates to the lethality of the handgun in practical use. Because otherwise, you’d have to include the .357 Magnum data with the “medium” calibers. Does that make sense?

Well, intuitively, it does. I think most experienced firearms users would agree that in general, a more powerful gun is more effective for self defense (or for offense, which this study is about). Other things being equal (ability to shoot either cartridge well and accurately, concealability, etc), most of us would rather have a .38 Sp/9mm over a .22. But when you start looking at the range of what they call “medium” and “large” calibers, things aren’t nearly so clear. To borrow from a previous post, this graph shows that the muzzle energies between 9mm+P, .40 S&W, and .45 ACP are almost identical in our testing:



Note that 10mm (and .357 Sig) are another step up in power, and that .357 Mag out of a longer barrel outperforms all of them. This graph doesn’t show it, but .38 Sp is very similar to 9mm, .45 Super is as good as or better than .357 Mag, and .44 Magnum beats everything.

So, what to make of all this? This claim:

Relative to shootings involving small-caliber firearms (reference category), the odds of death if the gun was large caliber were 4.5 times higher (OR, 4.54; 95% CI, 2.37-8.70; P < .001) and, if medium caliber, 2.3 times higher (OR, 2.25; 95% CI, 1.37-3.70; P = .001).

certainly seems to carry a lot of import, but I’m just not sure how much to trust it. My statistical skills are not up to critiquing their analysis or offering my own assessment using their data in any rigorous way. Perhaps someone else can do so.

I suspect that what we actually see here is that there is a continuum over a range of different handgun powers and lethality which includes a number of different factors, but which the study tried to simplify using artificial distinctions for their own purposes.

Which basically takes us back to what gun owners have known and argued about for decades: there are just too many factors to say that a given cartridge/caliber is better than another in some ideal sense, and that each person has to find the right balance which makes sense for themselves in a given context. For some situations, you want a bigger bullet. For other situations, you want a smaller gun. And for most situations, you want what you prefer.


Jim Downey


July 29, 2018 - Posted by | .22, .25 ACP, .32 ACP, .357 Magnum, .357 SIG, .38 Special, .380 ACP, .40 S&W, .44 Magnum, .45 ACP, .45 Super, 10mm, 9mm Luger (9x19), Data, Discussion. | , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,


  1. They did a pretty dang good job on the statistical side if things. The separation of factors before evaluation of “caliber” was a great way of conducting the study. However, I have a problem with their definition of”lethality”. They acknowledged that multiple hits and their placement were more dangerous than a single hit but they neglected to factor in the number of hits per caliber. Follow up shots are easier with a smaller caliber especially for unpracticed shooters. I can think of several possible reasons why this analysis excluded this factor. One, they didn’t know that “caliber” effects accuracy. Two, the data wasn’t available on the number of shots taken compared to the number of hits. Or three, if that was included in the analysis it would change the desired results.

    Comment by Adam Peterson | July 30, 2018 | Reply

    • All good points. Thanks for sharing your thoughts!

      Comment by James Downey | July 30, 2018 | Reply

    • The FBI at one time stated the the 13+ round 9mm pistol was the most leatheal handgun in America. This was due to the combination of magazine capacity, controllabiltly, lethality of the round.

      Comment by Jack A Furbush | July 30, 2018 | Reply

  2. A caliber is one inch, the bullet diameters are in the. Less than one inch a Naval gun 5inch .54, us 5.54 caliber, the bigger and the faster, more damage, but all depends on velocity

    Comment by Raymond Gatley | July 30, 2018 | Reply

  3. Handgun or any gun shot wound is potentially fatal. The caliber of the bullet ( size ) is not as important as what the bullet hits and deamages or destroys. Blood loss is the most common cause of a fatal gun shot wound, there for the size of the bullet is irrelevant. The end result is the same. Style and velocity my make death come faster, but the victim will be just as dead. The fact that more people in America that die from a gun shot are killed accidentally by the .22LR than all of the center fire rounds fired in anger. The common myth that it makes a real difference what handgun and round selected is also dispelled by the fact that today we have so many to choose from and they all work equally well

    Comment by Jack A Furbush | July 30, 2018 | Reply

  4. Study is essentially useless on a few counts.

    1 the study only tracked Criminal shootings which I suppose eliminates self defense and police shootings.

    2 the study measures lethality which is ultimately not as relevant as stopping power.

    3 doctor should know more seti Firearms effectiveness then my gunsmith should do appendectomies.

    Comment by Mark Laderwarg | July 30, 2018 | Reply

  5. You are missing such a huge part of all the ballistic data. The only reference I saw was muzzle velocity doesn’t mean anything in the end you need to look at all the coefficients size of bullets powder behind it foot pounds so much more like I said the only thing I saw was one graph on muzzle velocity like I said there’s so much more to it you haven’t complete data there for your conclusions are based on limited data. I think the biggest Factor in The lethality is actually going to be shot placement

    Comment by Chris | July 30, 2018 | Reply

  6. Thank you for this. When I originally read this on Vox, I was horribly confused about how they ended up with 7.62 ending up in the large caliber category and .32 in the small caliber. Also. .223 was never mentioned at all. I just didn’t know what they were trying to say

    Comment by Mark | July 30, 2018 | Reply

  7. As far as I’m concerned any well placed shot can be lethal no matter what caliber or cartridge you use.

    Comment by Robert McFrederick | July 30, 2018 | Reply

  8. I was surprised by my concealed carry permit instructor for him to say that a 22 could be more lethal than a large caliber shell, you don’t have the knockdown but the bullet doesn’t immediately exit the body it bounces around inside and takes out several organs.

    Comment by Craig | July 30, 2018 | Reply

    • Shot placement trumps bullet size, also as a certified sworn law enforcement person,dcjs va.most leos I know do not go to work hoping to get in shootout,only rookies and armchair troopers.

      Comment by Offier Douglas | July 30, 2018 | Reply

      • No one ever said that shot placement is not paramount. However, when similarly and properly placed the larger caliber will trump the smaller ones.

        I’ve been a cop for over 33 years and only in my retired armchair for a few.

        Comment by Mark Laderwarg | November 5, 2018

  9. As a person who carries weapons as a condition of my employment dcjs va,sworn and certified,most leos,I know do not go on duty hoping to get in shoot out,shot placement trumps bullet size.The only people I here about talking about gun fights are those who go the other way when rounds start flying.

    Comment by craig Douglas | July 30, 2018 | Reply

  10. Jim,
    I’m glad you pointed out the misuse of the word “caliber.” That bothered me because I don’t think the author recognized his error. If you follow his thought process a 45 acp would be more lethal then say a 300 win mag, since it’s a larger caliber.
    Obviously caliber alone tells us nothing about potential lethality without also knowing the weight of the bullet and the velocity produced.

    Additionally I didn’t follow his connection to the phrase, “guns don’t kill people….” The article never addresses that the phrase is referencing the fact that guns are inanimate objects not whether or not they are lethal.

    Comment by TYLER CAMPBELL | July 30, 2018 | Reply

  11. This is funny, I went to ballistics by the inch to try to compare different calibers and different barrel lengths, to see overlap.

    My reason is to figure out what to use in the present day Barbie dolls of handguns, Glock 21, 22 and 23. The 21 is a large frame .45 which can take a 10mm conversion barrel and a bunch of other less common chamberings (the Glock 20 is similar but less compatible, it can’t go up from 10mm to .45 without a new slide), the 22 is the full size version of their smaller frame gun in .40 S&W so it can do 357 Sig and 9mm conversion barrels and the 23 is the compact version of the 22, just a shorter barrel and shorter grip, otherwise almost the same and with the same vibrant aftermarket.

    I think I have settled on 10mm and 357 Sig because 10mm is very close to the top of what can be done in a large frame pistol and much more common than anything that can best it and 357 Sig seems to pack the most punch in smaller frame pistols while beating most .45 ACP in terms of energy. That’s what I call overlap.

    I think it would be interesting to see you do more editorializing about the trade offs between different calibers and maybe look in to ballistics gelatin as a way to quantify ballistics performance beside velocity and energy.

    I personally think energy correlates very well with terminal effect but it’s hard to convince people when comparing a 125 grain .355″ vs a 230 grain .451″.

    Comment by Dan | November 4, 2018 | Reply

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