Muzzle velocity and stopping power

I’ve had two posts in the last couple of weeks regarding ammo selection for self-defense, one on the .38 Super for self defense, and the other denigrating the 10mm.  We also did an episode of Gun Nuts Radio that focused on terminal ballistic performance.  Out of all of this, one of the comments that will usually show up at least 10 times is where someone touting the .357 Sig or the 10mm will point and wave and stamp their feet about how much more muzzle velocity their part cartridge has.  Stop it.  I have linked to this image so many times that I’ve lost count, but here it is again.  Now, we’re not talking about hunting rounds here, because I’m not a hunter, so I’m going to confine this discussion solely to defensive ammo for two legged badguys.

Look at that graph.  See how every single round penetrates more than 12 inches and expands to roughly 0.50-0.60 inches?  The 9mm, the .40, the .357 McSilly, the .45 ACP all do exactly the same thing.  They all have a permanent wound cavity that is virtually indistinguishable from one round to the next.  So all that extra 100 FPS you’re getting the .357 McSilly or the 10mm isn’t actually going to make a difference in terminal ballistic performance.  When you’re thinking about touting a pistol cartridge because it’s a “better stopper” because of all the muzzle velocity/kinetic energy/magic it produces, remember this from the definitive resource on handgun wounding:

Kinetic energy does not wound.  Temporary cavity does not wound.  The much discussed “shock” of a bullet impact is a fable and “knock down power” is a myth.

If you want to carry the .357 Sig or the 10mm or some other boutique cartridge, that’s fine.  I’m certainly not going to stop you from running out and buying a Springfield XD in .45 GAP.  But don’t fool yourself into thinking that your bullet is going to do something special in terms of damage to the target.  If you’re using a modern, “service type” hollow point load, guess what – it’s going to penetrate 12+ inches and reliably expand regardless of whether it’s a 9mm, a .40, a .38 Special, a .357 Sig, a .45 ACP, or a 10mm.


  1. After looking at that image, I am quite comfortable knowing that if I am ever attacked by a large block of gelatin, any round I happen to have on me will do.

    Of course, add a bit of denim / leather jacket, some bones, muscle, and a tendon or two and then rerun those tests 😉

  2. On the whole, I agree with your position and summation., but some cartridge and gun combinations are intrinsically more accurate than others for different people and that is the KEY factor; Can you put the round where it needs to go while under extreme stress?

    (I’m not sure muzzle velocity is a factor in that question.)

    All The Best,
    Frank W. James

  3. Frank, now that’s something I definitely agree with. In my mind, the platform that someone chooses from which to launch their chosen projectile is of much greater importance than the projectile chosen. I always tell newbies to find the gun that you can use with speed and accuracy, and don’t worry about “stopping power”.

  4. I need to find the link, but there was a coroner in Atlanta that discussed the real effects of various calibers. He talked about the multiple perforations from the 9mm vs the absolute damage caused by the .45 or the .357 magnum.

    Ah, here it is –

    He has some great points, this one being my main reason why I don’t buy into the gelatin argument

    One of the benefits of working in a morgue is that I get to see what works and what doesn’t. Ballistic gelatin is good as far as it goes, but there’s nothing like seeing what a bullet actually does once it strikes bone, flesh, and organs. Suffice it to say, it doesn’t always mimic ballistic gelatin.

    He also agrees that a bb to the eye can be lethal and that he’s seen a headshot with a .44 Magnum that didn’t penetrate the other side of the skull.

    Of course, the best way to double the effectiveness of any caliber is to follow up with another shot.

  5. The only problem with a coroner studying bodies is that he’s getting guys that are already dead, and has no way of knowing how that person reacted to getting shot, how long it took them to die, etc.

  6. Caleb is correct. The coroner also has a horrible selection bias in that he doesn’t see the guys who live. I’m also somewhat wary of the coroners analysis as it is full of “everybody knows” statements that make me wonder where his personal experience ends and less empirically based knowledge begins.

  7. Its my understanding that certain rounds were developed specifically to meet certain requirements that were otherwise not met with an existing cartridge.

    The 357sig was designed with several requirements in mind.
    – Faster than a 9mm
    – Fit the same size frame as a 40s&w
    – shorter than a 38super

    It was designed exclusively with law enforcement in mind, and to be marketed to agencies both domestic and overseas. Many countries have regulations regarding the use of calibers other than a 9mm/.356 bullet. (Mexico comes to mind) So, the 40s&w is essentially outlawed.

    Not saying its a perfect cartridge, only that it meets a specific need. And as the test indicate, it is certainly sufficient as a “man stopper” in that it expands quite well in jello.

    Nope, don’t own one, and probably never will. But, that said, those that own them tend to appreciate their capabilities.

  8. The 357sig was designed with several requirements in mind.
    – Faster than a 9mm
    – Fit the same size frame as a 40s&w
    – shorter than a 38super

    All of these are marketing requirements and count exactly jack and shit towards wounding potential.

  9. There’s a version of that image I saw on a thread discussing 10mm once. They’d added in a 10mm shot and photoshopped in a nuclear explosion into the gelatin. It was pretty hilarious. 🙂

    I also find it interesting that when this comes out and the inevitable “I’d rather be able to shoot a lot” comments show up everyone ignores the double stack 45s. Of course they’re a minority, to be sure.

  10. I agree with most of what you said. But different rounds will have different results and a 9mm won’t perform just like a 10mm. The 10mm will have more velocity and penatration, but the 9mm will expand better. So in the end it will all depend on the ammunition you use and your accuracy.

    Custom Cast Bullets and Jacketed/JHP Bullets.

  11. Mike, I agree with that, but from a “functional” defensive standpoint, factory ammo in 9mm or 10mm is going to be designed to have the same terminal ballistics.

    Handloads are a completely different equation.

  12. PDB,

    You’ve left out a key criteria in the original development of the .357 Sig:

    EXACTLY duplicate the ballistics of the Marshall-Sanow top performer, the 125 grain .357 Magnum JHP, in a round that could be stuffed by the handful into a reasonably sized service pistol.

    Right approach or wrong approach — THAT was the approach. Take a known good perfomer in revolvers, and make a clone that works well in high capacity semiautos.

  13. My factory carry ammo gel tested out at 15.0 inches penetration and .84 inches of expansion, after 4 layers of denim. I suppose if your job doesn’t require math, 12 inches and 15 inches are approximately the same, and .60 and .84 are pretty close. But, referring to your beloved picture, I rather think that 15 inches would be somewhere past the right side of the image, right? Hmm. SO, why exactly is the number one performer — .357 Magnum — absent? It’s almost as if you are trying to hide something.

    Caleb scores another win with the guaranteed blog hit-o-matic: say something utterly indefensible and watch the sparks fly!

  14. Hooray, your carry ammo outperforms the FBI standard, which proves absolutely nothing other than your carry ammo outperforms the FBI standard! Way to miss the point, as usual. I’d recommend that you get your own blog, but I doubt anyone would read it.

  15. Hilarious as usual: make a claim with authority, then when that claim proven to be false, deny the distinction with authority. Throw in ad hominem attacks. You know, there’s a technical name for that particular psychopathology.

    Start a blog? Me? But Caleb, I don’t have narcissistic personality disorder. I’m a normal, well-adjusted person that doesn’t treat people like toys.

  16. That would be rad except for the part where you didn’t prove anything false. I suppose if you’re feeling pedantic I could have said “at least” 12 inches, but I figured we were all smart enough to figure that out.

    Guess I was wrong.

    Hey, isn’t the part of the conversation where your storm off in a hissy fit?

  17. Except “at least 12 inches” isn’t even the same thing as “outperforms the FBI standard”. How do you “outperform” a 40 battery test at various distances and barriers with a pass/fail result on each test?

    Do you even know what the FBI testing procedures were? Why was 10mm chosen, when 9mm would easily penetrate “at least 12 inches” on bare gelatin? Every tested load passed some of the tests, only two loads passed all.

    What were they? I’ll give you a hint — neither is on your “every caliber is the same” picture.

  18. Hilariously enough, I happen to have a copy of the FBI ballistic standards sitting on my desk. The standards mandate that in the bare gel test, the round must penetrate a minimum of 12 inches in bare ordnance gel, with 16 inches of penetration being “desirable”.

    At the time the tests were initially run in the late 80s, only two rounds “passed”, the 10mm and the .357. That would be important, if it wasn’t for the fact that since the FBI standards became the national law enforcement standard, many, many, many, many loads have passed the test including numerous loads in 9mm, .40 S&W, .45 ACP, and yes even .357 Sig.

    While the original results achieved in the 80s were interesting, we have seen significant advancement in bullet technology since that time; a fact which the FBI itself acknowledges as their current load in .40 S&W precisely duplicates the performance of the 10mm load selected back “in the day.”

  19. Wow, I’m impressed: you were able to write 3 factual paragraphs without a single logical fallacy. Let’s keep up the good work!

    16 inches of penetration is still desirable.

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