Why Bullet Statistics are Useless

What matters when choosing your self defense ammo?  Is it the muzzle energy?  Is it the velocity?  Is it the bullet weight?  Which of these statistics is most important?

NONE OF THEM.

(cue the internet howler monkeys, lining up to scream and throw poop at me, but stick with me for a minute please…)

Bullet weight, in and of itself, is not an indicator of terminal performance.  Neither is muzzle energy.  And neither is velocity.  In fact, they’re all interrelated — if you use a heavier bullet, it’s likely that the velocity will go down (and, when velocity goes down, muzzle energy usually goes down).  It’s easier for a cartridge to throw a lighter bullet faster than a heavier bullet, so for any equivalent powder charge, the lighter the bullet, usually the faster it travels, and the faster it goes, the more likely that the muzzle energy will be quoted as higher (since the formula for energy is (velocity squared x mass x 0.5), so any increase in velocity is going to have a much bigger impact on total energy figures, than any similar increase in weight would.)

Some manufacturers take advantage of that, making deliberately ultra-light projectiles, which will then travel faster than other manufacturers’ projectiles, which lets them quote much higher muzzle energy and velocity figures.

But what does that mean?  Not a whole lot.  What matters isn’t the velocity, or the mass, or the weight of the bullet — what matters is: what does the bullet do when it hits the flesh?  How deep does it penetrate? Does it reach and disrupt the vital organs? Or does it just impact on the surface or make a nasty flesh wound?  Does the bullet expand to a larger size? Does it stay on target or does it wander around and veer off course?  Does it plug up with clothing and fail to expand?  Does it stop in the body or does it zip right through?

Those are what matter.  And you can’t figure out ANY of those answers by studying weight or muzzle energy or velocity.  For example — assuming an identical powder charge, ANY 124-grain bullet is going to have identical weight, muzzle energy, and velocity as ANY OTHER 124-grain bullet.  So a 124-grain full-metal jacket is going to have identical weight, muzzle energy, and velocity as a 124-grain hollowpoint.  But their terminal performance will likely be extremely different.  In fact, that’s really the point behind Winchester’s new “Train & Defend” line — they’re making the identical same ammo in self-defense and practice rounds.  But even though the weight, energy and velocity are identical between the two, the “Train” rounds would be lousy choices for personal defense, as compared to the “Defend” entries in their lineup.

Let’s take it to a silly extreme — if you were to pack 124 grains of corn flakes into the shape of a bullet and jam that into a 9mm cartridge, and successfully fire it, it would have the same muzzle energy and same velocity and same weight as a premium 124-grain Federal HST bullet.  But which do you think would be a more effective manstopper — an HST, or a wad of corn flakes?

The specs printed on the box don’t matter (much).  What matters is what happens when the bullet hits the flesh.  How it rips, cuts, tears or crushes flesh, and how much flesh it destroys, and how reliably and repeatably it does so, are what determines what makes a successful handgun bullet.  Not the ft/lbs of energy printed on the box.

Standardized testing (especially of multiple rounds) is designed to answer those questions.  But even then, there’s a further variable that has to be accounted for, and that’s what barrel length you’re using.  A test from a 4.6″-barrel service/duty pistol might show brilliant results for one particular type of ammo, but if you’re using a 3″-barrel concealed-carry pocket pistol, that exact same ammo might perform miserably from your pistol.  An example might be a 147-grain bullet that travels at 1000 feet per second from that 4.6″ barrel, and expands hugely, and penetrates 14″ — that’d be great.  But the 3″ barrel likely can’t impart that much velocity, so the identical same ammo might travel at only 900 feet per second, which might be too low to force the bullet to expand, so it might fail to expand and end up zipping right through your target, penetrating 32″ or more, which means it’d have (comparatively) very little terminal effect on your target, but would instead pose a big risk of overpenetration.  Same ammo, very different results — so testing can be informative, but only if the testing is comparable to what you’re going to be using.

So don’t be swayed by marketing, or by numbers printed on the box.  Look for some qualified testing that shows how the bullets really perform.  And, ideally, look for testing that’s done from a comparable-sized pistol as what you’ll be using.  And the more the testing conforms to industry standards, the more informative it will be.

I wish it was easier.  I wish we really could just look on the box and see meaningful statistics (barrel length, penetration depth, and expansion size) but the manufacturers don’t list that; instead they give us weight, velocity, and muzzle energy… and those aren’t actually useful in helping us know what’s really important: how much damage will this bullet do to human flesh if you (heaven forbid) you ever found yourself in a situation where you needed to use it against an attacker.

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8 thoughts on “Why Bullet Statistics are Useless

  1. www.tiwler.com

    You really make it seem really easy along with your presentation but I find this topic to be actually one thing which I feel I’d by no means understand.
    It sort of feels too complicated and extremely extensive for me.

    I am looking forward on your subsequent publish,
    I’ll try to get the hang of it!

    Reply
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  3. rw walden

    i think he is saying stats about stuff other than shot placement, expansion and penetration are useless for making a decision about what to carry and what to ammo to shoot. also, it is dangerous to predict performance from one circumstance to a different one; every combo needs to be tested by the individual making the decision (testing can be a data review and live fire of the desired combination…not everyone can set tests like STb).

    cheers,

    Reply
  4. Richelle

    Hi there this is kind of of off topic but I was wondering if blogs use WYSIWYG editors or if you have to
    manually code with HTML. I’m starting a blog soon but
    have no coding skills so I wanted to get advice from someone with experience.

    Any help would be enormously appreciated!

    Reply
  5. Aaron

    Just curious if two bullets both reach 12″ and both expand to .50″ but one is traveling faster or is heavier, or carries more energy will it do more damage or the same as the other round? Wasn’t sure if the body responded to the energy transfer or not. I know pistol rounds does not travel fast enough for hydrostatic shock but the same question could apply to a rifle as well.

    Reply
    1. Shooting The Bull Post author

      You ask an interesting question, with a complex and theoretical answer, and one that I don’t feel fully qualified to answer. For example — if you had a bullet that expanded to .50″ and fully penetrated the body, and you had another bullet that expanded to .50″ and fully penetrated the body, would one do more damage than the other? Seems like the simple answer is “no”, but if we compare a .50-cal FMJ against a 9mm hollowpoint, no doubt the hollowpoint would do much more damage on its way through. Bullet construction plays a big role in how much damage is done; a sharp-edged expanded hollowpoint can shred flesh that a smooth-nose FMJ would just slip through, causing comparatively very little damage.

      So — how can you possibly get two different bullets to stop at the same spot, expanded to the same size, but have different velocities or different weights? Something is going to have to change in the bullet construction. A very lightweight bullet at enormous velocity might be able to penetrate as far as a very heavy bullet at a slower velocity, for example. Using the Schwartz formula, a 230-grain bullet that expands to .50″ and reaches 12″ deep penetration needs just 364 feet/sec of velocity to do so. And it would carry just 67 ft/lbs of energy. Now, to get that kind of depth and expansion from a super-light bullet (say, 50 grains), you’d need nearly 10x the velocity(!) It would require 3700 feet/sec to push a .50″ expanded 50-grain bullet to 12.00″ penetration. And that would mean 1,520 ft/lbs of energy(!)

      What would be the practical differences here? Well, according to the calculations, the mass of the permanent cavity of destroyed tissue would be the same in both cases (32.89 grams of tissue destroyed). But the size of the temporary stretch cavity would be enormously different — the big bullet, at such low velocity, would probably create little observable temporary stretch, and certainly not enough to actually do any damage. It is generally regarded that you’d need over 2,000 ft/sec of velocity to create a temporary stretch cavity that would begin to overcome the elastic limit of flesh and actually start tearing the flesh, instead of just stretching it out. At 3,700 ft/sec, I’m sure that the size of the temporary cavity would be so large that it would be a major contributor to damage done, not through the bullet cutting a hole, but through the tissue being stretched beyond its ability to bear and it just ripping instead.

      Now, the two extremes listed here are not really practical comparisons; 364 fps vs. 3,700 fps is such a stretch that it’s hard to imagine how you could have both. Generally a .45 ACP (230-grain) is going a lot faster than 364 fps (usually 850fps+) and a .223 rifle (50 grain) is usually going slower than 3,700 fps (Federal makes a .223 JHP in 50-grain size that travels around 3,300 fps). Which would be the more potent manstopper? The .223 round, at that massive velocity, will likely create much more tissue damage than the pistol round, because of the secondary wounding effect of the temporary cavitation.

      But that’s a rifle for you. Rifle wounds are in a completely different class than handgun wounds…

      Reply
      1. Aaron

        I wasn’t really wanting to compare a rifle round to a pistol but was just saying we could talk rifle vs rifle or pistol vs pistol. I see your point and appretiate the explanation. Let’s compare a 115 Grn 9mm +p at 1250 or so vs a 147 grn at 1000. If they both ended up the same diameter and depth would there be any difference in the damage done? One is traveling faster the other heavier, I was just curious in a comparison like this if it mattered at all which bullet you chose.

        Reply

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