Previous Post
Next Post


By Clint

When I was young, my interest in guns was as any other child’s was. Namely an interest in the idea that guns made you strong. As I got older, I grew out of that, they weren’t strength, they were tools, and real strength was determined by other factors. At a time in my life where a young person’s interests are shaped, I got into video games. Guns weren’t interesting, cool, but not a fascinating topic, but one game I played changed that in an odd way.

Tom Clancy’s Rainbow Six got me interested in the topic of firearms. Though it wasn’t the idea of playing a super secret squirrel agent of an oddly named international anti-terrorist group that got me hooked. What caught my interest was a decision the player must make when gearing a character. FMJ or JHP? As a kid my response was “I dunno” but I was a curious kid, and I wanted to know. Which is better, and which should be used and when?

That’s what got me into guns. As I learned more, I came to research ammunition, and later, guns themselves. All while learning to brush aside what I call “Projectile Vomit”. Basically, this covers any comments being spewed by a person with a near religious fervor for a specific caliber, brand, or type of projectile, or an equally exceptional lack of understanding of ballistics, and no real information to back up the claims.

“A .45 caliber will kill the soul” “.40s suck” (this one’s actually probably true, but the hypothesis still qualifies) “FMJs are like ice picks, in the body, while Hollowpoints are like bombs” “.45 because shooting twice is silly” These are all examples of projectile vomit.

Now that I’m older, and looking into ammunition for a more hands-on version of the hobby, the projectile vomit is getting more and more sophisticated. Usually involving Dr. Sydney Vail, FACS vs. Dr. Gary Roberts, DDS, or vs. Or nearly any sentence that begins with “The FBI and IWBA.” The biggest instances of projectile vomit I’ve noticed in the area of ballistic research involves sectional density and momentum.

Sectional density is one I had to look up. I was familiar with tensile strength and elasticity and stress/pressure, but sectional density was a new one for me. So I looked it up, and hoo-boy did Wikipedia fail. The line “SD_Ballistics = Mass/Diameter^2 (approximately equal to) pressure” immediately showed me what I needed. (Funnier even, right after saying approximately equal to pressure, they got the derivation for the Pascal wrong).

The only instance sectional density would be approximately equal to pressure is if every bullet of a given caliber moved at the same velocity as every other bullet of the same caliber regardless of mass.

To explain, pressure is force applied to a given area ex. kg/(ms^2) (the Pascal) or lbf/in^2 (or PSI). Note that the description of the PSI is not a typo. PSI is not pounds (weight) per square inch; rather it’s pound-force per square inch. Both of these consider force, which is a function of mass and velocity (specifically the change in velocity over the change in time, aka. acceleration), whereas sectional density only considers mass. Why is this important? Simple, bullets fired from different cartridges have, both, different mass and different velocity.

This also transitions to the second mentioned issue of momentum. Momentum is the velocity of an object modified by the object’s mass and vice versa. Momentum doesn’t grant any special powers; rather it’s just an observation of two attributes of an object at a given moment in time. If you increase mass of an object by 63.33%, you have to retain at least 61.23% of the velocity, to get the same momentum (1.6333 * .6123 = 1.0001). For reference 63.33% is how much of an increase in mass you get, when going from a 90gr projectile to a 147gr. This means that you only increase the momentum from a 9mm, when you go to 147gr from 90gr, if your 147gr velocity is at least 61.23% of the 90gr projectile’s velocity.

Pop quiz: which has more momentum, a 77gr. SMK .223 at 2750fps or a 147gr. 9mm HST at 1050fps? Would you believe someone who told you that simply because of the increased mass, the HST has more momentum?

The projectile vomit comes when people claim that because of sectional density and momentum, the heavier the bullet, the greater the penetration. In other words, when the claim is made that light and fast is, due to physics, not capable of performing as well as slow and heavy, regarding penetration and reaching vitals you have projectile vomit. This quite simply can’t be true.

Because more momentum means it will take more force to slow an object, in a given timeframe, and both mass and velocity are factors, it shouldn’t matter which get’s increased vs. decreased as long as the correct proportionate change is maintained. Additionally as stress is the determinant for overcoming tensile strength, not sectional density, a lighter and faster bullet that has more energy to apply more force to the same area, will then apply more stress to an object, and obviously penetrate better. As stress is force per area not mass per area.

Does that mean that light and fast is the way to go? Maybe not. There are a multitude of factors to terminal ballistics, and obviously heavy/fast would be the ideal. A heavier projectile moving at velocities closer a light/fast round, would have more energy for use in the same area, more momentum, and more material to work with when expanding/fragmenting, but that’s not sectional density and that’s not momentum ignoring velocity’s role. What this does show is a level of projectile vomit that should make you take a step back and not necessarily take everything an institution or expert says as ballistic gospel, and instead look and rounds and their given attributes against others, without preconceptions and pre-decisions.

So, two questions for readers: First, what is the worst instance of projectile vomit you’ve ever heard? Bonus points if it’s this article and you can show me I’m wrong. I do love it when that happens. Second, do you enjoy researching the ammunition and what makes a round effective as much as looking into guns themselves?

Previous Post
Next Post


  1. Discussions about handgun caliber ballistics are the domain of the geardos.

    Better to focus on accuracy and speed, in that order.

    You can drool over ballistics but a miss is the great equalizer.

    Put several rounds of any good JHP ammo into center mass and let others nerd it out over 9 or 40 or 45

    • Are you the TTAG forum police? Damn, what is it to you if some people like to talk about calibers and their differences?

      You’re not required to weigh in (considerably, in your case. See what I did there?) on everything that someone else says here.

    • I like to phrase it “If you want stopping power, then why do you have a handgun?”

      You said it right. Speed and accurate hits.

      I gave up on the caliber wars and went 9mm because dangit I shoot it well and pretty fast to boot.

      To me, “I carry X gun in Y caliber” only tells me whether I can ask for a mag if my two run out.

      • I also use 9mm since I shoot quickly and it is well suited to that. I still like .45 acp due to the quietness of it and because of the Thompson.

    • You bring out that same red herring every time caliber is mentioned. 9mm = fast, shots on target, implying that you can’t also get quick shots on target with a .40 or .45.

      • I suspect that for the vast majority, is easier to be fast and accurate with a 9mm than with either the .40 or .45. It doesn’t mean that you can’t get fast with those, it’s just easier with the 9mm.

        • If you shoot fast and accurate with a 9mm Glock, and you like the feel, and it’s fun for you to shoot, go for it. Practice and get good with that Glock, because that will serve you better than a different pistol that doesn’t fit you as well and you have a harder time getting good with. Me, I prefer my old, all steel pistols and/or a big ol’ .45 caliber round, though I have to admit to liking the feel of a CZ75…..

        • I don’t use a Glock, loathe the things. Prefer a CZ SP01. If you like .45 there is the CZ97, though it has “only” 10 rounds per magazine.

      • True, and a whole other article. Most people do shoot most 9mms faster with comparable accuracy to most .45s but this is a function of the relative recoil. Given a shooter of fixed strength and skill and two pistols of the same weight and ergonomics they should shoot to the same level of accuracy but be able to do so faster with the lighter recoiling 9mm.

        However, if the comparison is between a very small and light 9mm and a large, heavy .45 the difference goes away. Also not all shooters have the same strength, skill and experience level. Some shooters can hit so fast and accurately with an air weight .44mag that to tell them they need to carry a 9mm is insane (Miculek comes to mind here). That among the common three; 9,40, and 45, the 45 is the most effective in pure performance on target isn’t even open to debate, the best possible loadings of 9mm don’t reach the performance of mid grade 40s and the hottest 40s can’t compete with hot 45s. This is where case capacity and bullet size/weight make the physics impossible to deny. After this, where performance is the only factor, one should use the heavier of the calibers that one can shoot with reliable speed and accuracy.
        This, however is a pure performance argument. The reality is that most 9mm ammunition marketed for SD is already sufficiently lethal, provided good shot placement, that more is not needed. That isn’t to say though that more isn’t desirable, and that is why .40s and .45s exist, to provide more. I’ll never exactly understand the physics defying arguments regarding 9mms Vs .45s other than to understand tuners Vs old school hot rods, it’s just something people like to argue about.

        To ‘projectile vomiting’: There is a need to explain the empirical evidence that larger, heavier bullets moving at mild velocities seem to result in more likely and more rapid incapacitation than smaller, lighter projectiles moving at velocities which on paper should give them equal energy. That this has been seen in both hunting and combat is irrefutable. What is wanting is some reasonable explanation of the phenomenon.

        I suggest that it’s a function of perceived impact. Lighter, faster rounds of smaller diameter might tend to deliver less perceived damage as compared to larger, heavier rounds moving more slowly. The ballistic conundrum might have a physiological explanation. I doubt we’ll ever know, since it would require the either the same person being shot in a similar location with various loadings of various calibers to report on it, or else a large sample of people shot in similar locations with various ammunition articulating their perception of the wound.

        • “45 is the most effective in pure performance on target isn’t even open to debate”

          Um, no. With modern ammunition technology, 9mm is the same as 40 and 45. Wound channel findings are identical, 9mm gives me a LOT more capacity, and faster shots on target.

          There is simply no reason to use 40 or 45.

        • If arguing over caliber is considered Projectile Vomit, then arguing over Glock vs. 1911 would have to be Projectile Diarrhea. James Yeager can take his 4th-grade sophistry and cram it.

        • @Lucas D

          Um JY is a veteran, former cop, and trains students from all over. I think he knows a thing or two about guns! If he recommends 9mm, I’m going to listen.

        • Never go full Yeager.

          1. He was canned from his hick town police department, oh, wait, not once, but canned twice. He wanted to create a SWAT team for the tiny town.

          2. He is not a veteran. Never served in the military. Pulled a stint as a contractor and managed to screw the pooch in a major way doing that.

          3. He happily takes the money of people who come to him for his brand of tactical ninja training.

          4. He is going to start shooting people!

          Never go full Yeager.

        • Can you really trust a guy that says all guns should be brand X? I personally love CZs but I know that they aren’t the best choice for everybody. If I would recommend a gun it would be what fits your hand (or a CZ).

        • RJ… wow. You need to branch out a little from your JY worship. And even if someone is a “former cop” who trains people, it doesn’t mean they know everything… or anything really… about guns.

          And your statement about calibers is ridiculous. Why would you think the same improvements in 9mm would not also be applied to .45? A 9mm may be able to expand to a .45, but a .45 can expand to a .70. I’m not saying one is better than the other in general, but if you’re looking for a larger perm. wound channel don’t expect the 9mm to perform the same as a .45 (low-velocity cavitation and all that nonsense is a whole other issue).

      • Not a red herring if it is true. Sure, I am fast with a steel framed .45, but I am faster with a steel framed 9×19 mm.

        EDIT: Meant as a reply to the *you bring out the same red herring” comment by Yeah.

        • It’s a red herring when it’s presented as axiomatic. The guy said something about using a .45 and Paul came out with 9mm being necessary for fast shooting.

          Go with what works for you; if 9mm is what works best for you that’s good, but anecdotal. It doesn’t mean that no one else can get results with larger calibers.

  2. Being a techie, this article was cool!
    My best friends dad was a flight surgeon and a POTG whom I have great respect for.
    He has taught me volumes about ballistics, sectional density, ft/lbs of energy (both giving and receiving), flight path, wind doping….
    We have really neat discussions like this article while spending time reloading.

  3. I’m not certain I understand the question correctly, try this and see if it is a player in your game.

    During my long life, I have had repeated run-ins with people who INSIST that when a projectile leaves the barrel it immediately begins to rise, and then in some distance begins to drop. I haven’t been able to get anyone tell me just what causes this blatantly impossible rise, nor how a projectile spinning at 100,000+ rpm even knows which way is up or down, so that its internal control can decide which way it should go. But I have never convinced even one of these people that when the projectile leaves the barrel it immediately ceases accelerating and begins decelerating, and at the same time it begins to accelerate downward (a function of gravity, not rifle position, ie, if the gun is held upside down it does not alter which direction the bullet moves in) at 32 ft per second squared. Explain all day that they are talking about how the sights are set, a completely separate question upon which the shooter has significant input (Same cartridge, do you set it for 1″ high at 50 yards, or 2″?). Absolutely not, I am an idiot, EVERYBODY knows the bullet rises, then falls.

    I find that amazing, and I think it falls into your description of “projectile vomit”.

    • The US Army has a basic training graphic which depicts the trajectory of a 5.56 bullet relative to the sight plane of an AR. I think that is where the “bullet rise” idea got its start. When I was in basic training, I am pretty sure the marksmanship instructors actually told us that the bullet rose (as Sand Hill marksmanship instructors aren’t necessarily ballisticians).

      • As a source, I can believe that, but just where does the sight plane part just disappear? And why can’t I find anybody who believes that who can actually think?

        • It’s not that the bullet is actually rising as in, against gravity. It rises relative to your sight plane. It’s easier to explain with a drawing, but if you look through a rear and a front sight towards empty air, and fire the gun (as long as the bullet doesnt veer left or right), that bullet will rise up into your sight plane, then arc down back into it. This means the bullet crosses your sight plane at 2 points, these are called the near zero, and far zero. An example of this in use would be sighting M4s in at 25/33 meters, and the far zero being 250 or 300 yards. Because of the bullet rising up and then coming back down onto your sight plane, you can have the near zero for CQB, and the far zero for long range engagements. Hope this helps!

      • It’s like in 8th grade chemistry when the basically tell you that atoms have a specific number of “hands”, and when they hold hands they form molecules. It’s not really correct but it is sufficient for what you need to know at the time.

        • And that kind of crap is exactly what is wrong with science education.

          I’ve been involved in teaching chemistry for over 25 years, and I have NEVER once, not one single time, talked of forming molecules as “holding hands.”

          Why not just give the correct information to begin with? It’s not that hard.

          “Be very, very careful what you put in that head because you will never, ever get it out.”

          –Attributed to Cardinal Thomas Wolsey

    • I don’t know the conversations you’ve had with people. Never known you to lie, though, so I’ll accept that they proceed as you describe. Still, if it gets to the point where someone’s calling you an idiot, an obvious emotion-driven falsehood, then the conversation has already gone of the rails. Since you have the greater knowledge in those conversations, sorry, but I’m blaming you for ineffective explanation.

      People are reacting to you out of frustration twice: once because you’re contradicting something they’ve “known” for years, decades even, and again because they do not understand the concept you’re explaining. It’s fun (a little too fun in Paul’s case) to tease people for their miscomprehensions, but ultimately it does none of us much good to perpetuate myths of any sort about firearms; whether about their function, effect, history, legality, and so forth.

      A bullet’s trajectory vis-à-vis the line of sight/line of departure dichotomy is not the most complicated topic in all of firearms scholarship. Heck, at a rudimentary level, it doesn’t even require mathematics to explain; unlike MOA, which seems to blow people’s minds from the term “minute of angle” itself. Diagrams and patient explanation really should accomplish your goal with trajectories. It’s great that you’re out there having the conversations, though, and not giving up. Please keep it going.

    • With a properly zeroed rifle (especially one like the m16 where the sights are higher than the barrel by a couple inches) the sight plane will be aimed at your target and presumably parallel to the ground and the barrel will be pointing slightly upward. The bullet rises because it is pointing slightly up and will intersect your point of aim at 50 meters. It will continue arcing up until about 200 meters then it will begin to fall back down and intersect your point of aim again at 300 meters. Nobody throws a baseball directly parallel to the ground they arc it so it goes up, then comes back down.

  4. ” what is the worst instance of projectile vomit you’ve ever heard?”

    “Texas is not a gun friendly state.”

    • Agreed. People, typically those who don’t live here and have never visited Texas for any significant period, often say that. They employ a number of techniques in their sophistry.

      They’ll compare Texas to some ideal state that doesn’t even exist and then declare Texas woefully inadequate. Even worse, they’ll compare Texas in real life to the ridiculous “Wild Wild West” image they still hold from watching old T.V. westerns as a kid, then again declare Texas lacking.

      Alternatively, they’ll compare Texas to their favorite oh so gun-friendly state, except they’ll leave out important points of comparison altogether, and/or they’ll make errors in the points they do compare. Another trick of the Texas-haters is to compare states strictly on paper, as though there’s never ever been in all of recorded human history any deviation whatsoever between what the official written law is, and what the realities of its practice on the ground are.

      If you rank all 50 states and D.C. for gun-friendliness on a consensus weighted index consisting of multiple important and relevant criteria, avoiding the pitfalls mentioned above, you’ll find that Texas tends to rank easily in the upper half of states and typically in the top twenty. But hey, no need to take my word for it. People are free to google most gun friendly states. You’ll find rankings by various entities, such as Guns & Ammo, rank Texas respectably.

      For a more tongue-in-cheek approach, check out Brady Campaign’s State Scorecard. It’s letter grading, not ranking, so you don’t really know precise differences between same-grade states. Still, it’s fun as a negative measure. For the record, Brady gives Texas an “F”, which I interpret as “Freedom.” Shockingly, or not, even Brady’s favorite states like California, New York and Connecticut only earned grades of “A-“. This once and for all demonstrates that nothing short of outright disarmament through door-to-door disarmament and pogrom will ever be enough for these people.

        • Sooo……….you find a fault, which I readily conceded exists, and declare that Texas is not “Guntopia”? Nice. That’s a play on words with “Utopia” which, as I recall, refers to an imaginary place representing a perfect society; as depicted in Sir Thomas Moore’s 16th century fictional work of the same name. I’m certain you’ve read it.

          From my post: “They’ll compare Texas to some ideal state that doesn’t even exist and then declare Texas woefully inadequate.”

          Dude, you failed on the very FIRST point I just made! Epic fail. Just walk away.

        • @Derp – Houston

          “Dude”; you characters who post, then declare yourself the “winner” are ridiculous. I’m glad you like my portmanteau of gun and utopia. I am not comparing Texas to some mythical, nonexistent, impossible standard. I gave a very basic example: you can’t open carry.

        • Flail about all you want. It’s not about me winning anything. It’s about your comment stating the obvious and agreeing with mine, but with a twist of pointless attitude, and your comment’s failure to contribute any value to the thread. I acknowledged Texas was not the best in my own post. Your big contribution was what? The most common, known-to-everyone element of Texas’ gun laws, and executing the very error I discussed in the original post? Enlightening display. Thanks for stopping by.

          As always, I’ll let you have the last word, since I already know you can’t let it go and won’t take prudent advice just to walk away.

        • Okay, let’s go with high cost carry permits with equally expensive training requirements. There’s a whole multi-post series here on TTAG on what have to do to get a CHL. It’s about four times the cost and time required to do the same in Washington. Other states are even cheaper and faster.

          Or we can talk about 51% or 30.06 signs, whereas other states no anti-gun signs have any force of law.

          Texas is average. Good on some things, not great on a lot of things.

      • I don’t even really care about open carry. I would put us ahead of any state with a registry or mag size limits, which I bet would make us number 8 at least. The biggest pro gun state, hands down. Suck on that, ‘murca!

    • Ohio sounding in: I can legally walk down the street with a pistol on my hip, can you? if fact I’m about to take the dogs out to the public park next door, I don’t feel like a cover up in this fair weather so I’ll let my 1911 shine. When you can do that, you can say you live in a gun free state. So long as they are a dirty secret, you’re not free.

  5. @Larry, have you ever looked closely at a bullet? They have little wings that pop out and cause the bullet to rise to maximum ballistic efficiency when it leaves the barrel of a firearm.

    Geesh, I thought everyone knew this.

    • Ditto, what I know about ballistics is which way the bullet goes, how much it drops and that it hurts.

      Bet all the techies enjoyed this one.

  6. Bullets do rise when the firearm is pointed upward to meet the line of sight of the sight or scope. Shot horizontally, bullets immediately fall due to gravity.

    Looking at a trajectory chart which shows a rise (to meet the line of sight), it is easy to see how people get confused.

    • Makes no sense, how do they rise? They get shot out of the barrel and fall as gravity does its thing on them. sight line is straight, while trajectory is parabolic. This means that the sight line crosses the trajectory twice. What happens between those two points (where it is crossed by the sight line) can be understood as the bullet rising, while in reality you are just aiming below point of impact.

      Or were you being sarcastic?

      • Rise is caused by foward thrust and vertical lift, think bird.

        Bullets only have forward thrust, which can be angled upwards to create the same effect as rise. But, it’s not rise, think rocket.

      • Please reread. Bullets rise when the firearm is pointed upward to meet the line of sight of a scope or sight. This is because the sight/optics sit above the bore. If you point a scope/sight horizontally toward a target, the firearm must be pointed up in order to hit the target that the sight is pointed at. In relation to the ground the bullet will rise.

        Plotted out on a trajectory chart, the bullet rises to meet at the zero point–again, because the firearm is pointed upward.

  7. In practical fighting terms, Paul is right. Shot placement, number of good hits and shooting speed is far more important than which hollow point you use.

    Things become more complicated at extreme ranges in terms of flight characteristics and terminal effect.

    • Obviously you want to hit with whatever caliber you use. Who says that no one can connect with anything larger than 9mm?

      • First off, I didn’t mention any specific caliber. However, since you asked, there is no sense in hitting someone with a bullet only to do minimal damage. Only give the bad guy more time and incentive to attack you.

        • First off, you were saying Paul is right, and he was doing his usual thing, which is to dismiss talk of any caliber other than 9mm by talking about “fast shots on target”. Therefore, I asked why it is implied that the same shots can’t be achieved with .40 or .45.

          Thanks for playing.

      • Anon, You seem to have a severe reading comprehension problem.

        Rabbi said that Paul was correct in that “Shot placement, number of good hits and shooting speed is far more important than which hollow point you use.”

        Neither Paul, nor the Rabbi said anything about 9mm until you brought it up.

        Maybe you should go out and play and let the adults talk.

        • You’re the one with the comprehension problem, and a minding-your-own-business problem.

        • I too must be having a reading comprehension problem. I searched for “fast shots on target” and did not find in in Paul’s post, only your’s Anon. Neither did I find where Paul stated that 9mm was insufficient. He only said “Put several rounds of any good JHP ammo into center mass and let others nerd it out over 9 or 40 or 45.” which not dissing 9mm as far as I can comprehend.

          Perhaps you could illuminate my errors Anon?

        • @Rabbi

          You must be having an issue, as you’re saying the polar opposite of what occurred: I never said that Paul was “dissing” (to use your hip vernacular) 9mm, but rather that any time it is suggested that other calibers exist, he deems the conversation to be unnecessary, and launches into a diatribe of how 9mm is the bestest because you can fire quick, on target shots with it.

        • Anon,

          I guess I don’t get that interpretation from “Put several rounds of any good JHP ammo into center mass and let others nerd it out over 9 or 40 or 45”

          Seems to me, that he is saying that the caliber, 9,40 or 45, does not matter. What did I miss?

  8. what is the worst instance of projectile vomit you’ve ever heard?

    You may want to reconsider that question.

    • Please reread the 8th Commandment, Pope Paul. Or do you need me to post your apology to the synod?

  9. I love bullet talk and convincing myself I’m gaining something by carrying a .45, but it doesn’t really matter. It’s a handgun, just rhythm drill whatever you are shooting at and call it good.

    The thing is, too many people train to combat the hoodlum or criminal that they will never encounter, and fail to train against their true assailant, those evil shadows being heart disease, obesity, high blood preasure, and generally a lack of physical aptitude…

    By all means, train hard and keep those rounds center mass, but maybe go for a walk and try a do a pull up every now and again, and then step it up from there…

    To tie it all together, the biggest projectile vomit I read and see are all these “operators” on tactical life and other sites doing tactical this and tactical that but can barely fit into their body armor and are huffing and puffing after a string of fire…

  10. I had an argument once with a person who insisted that a projectile would always travel farther if fired from a rifled barrel rather than a smooth bore. After a few minutes of trying out the concepts of seal, spin-induced vortices, energy loss to inducing spin in the first place, and the like, I couldn’t actually get her to give a reason for why she believed this. (I was genuinely non-sarcastically curious, since it was a purely theoretical socratic argument on my part)

    In the end, she insisted that she was right because she was a physics major and had a 140 IQ. I told her that must be nice, and changed the subject.

    • She might have a point. A non-spinning bullet has a greater tendency to tumble, which wreaks havoc with range and accuracy. However, invoking her putative IQ and her major labels her as perhaps not the best person to have a relationship, or discussion, with.

    • There may be some truth to her theory. A “spinning” bullet is more apt to stay straight, on it’s way to the target. A projectile coming out of a smooth bore would be more likely to wobble after traveling a ways. which would of course slow it down.

      • In practice, and on average, we are agreed, and that’s at first what I thought she might base an argument upon. My question, however, asked if the unspun projectile might travel farther, under the unlikely, (but common in discussion of physics principles) assumption that the projectile was either perfect (I.E. no wobble), or that a given defect in the projectile actually affected the un-spun projectile on a lucky shot such that it deviated slightly upwards or generated some amount of lift which would otherwise be neutralized by spin-stabilization. It was an intentionally silly socratic question meant as an engineering challenge amongst bored collegians at dinner.

        However, as Mr. Unknown points out, the lady was not interested in being other than unpleasant, and clearly had no knowledge of elementary logical fallacies (I.E.: it would be equally Illogical for me to argue that the slug would go farther by citing my experience writing patents on aerodynamic features for a major aerospace corporation).

        Debates are a lot more fun if the participants realize they don’t have to add personal stakes. Up to that point it was an academic investigation, but after making an argument from authority, she put her expertise under judgment, and risked humiliation if proved wrong. I disengaged at that point, since I had only posed the question as a diplomatic effort to engage her on a topic of interest to her major because she was a friend of a friend, and new to our group.

  11. Almost any long gun beats a pistol for terminal ballistics. If you subscribe to big and slow, choose a 12 gauge using a slug. In a short range gunfight it’s hard to beat a 12 gauge with 0/0 buckshot. So many choices. So little time. Choose, then train to win. As a friend says, several rounds of any caliber with any bullet in the face and everyone looses interest in the fight.

  12. Worst instance of ‘projectile vomit’ I’ve encountered is still the ‘.45 kills the SOUL’ garbage.

  13. The “I won’t trust my life with plastic guns” thing is pretty ridiculous.

    I mean, if you just don’t like polymer guns, fine.

    But, you’ll strap your child into a plastic car seat, drive a vehicle covered in plastic, or what about pacemakers and plastic joints and bones…. Doc tells you that you need a pacemaker, what are you going say, “I ain’t trusting some plastic POS with my life…”?

    Let’s not pretend like we all don’t trust our life’s to plastic everyday once the gun talk starts.

  14. Every gun or ammo review I’ve read has given muzzle velocity decreasing within a few feet after exiting the barrel. Thereby negating a bullet rising. I’m no physics expert and I’ll leave it to you geniuses to determine whether light/fast is better than slow/heavy. Every gun owner should read “terminal ballistics as viewed in a morgue”. The author is a big fan of slow and heavy. I’ve never shot anyone so I can’t give a personal insight. How many people have YOU shot Rev McCain?

      • As do you and the rest of us. Is that not the point of the comments section? Also, I’ve noticed that your verbal pH has dropped rapidly over the past few months. Why?

        • “As do you and the rest of us. Is that not the point of the comments section? “

          Ostensibly, but Paul decrees what people can and cannot talk about. It is obnoxious as hell.

        • What the hell is verbal pH? And what happens when it drops? And who the hell are you? And why am I asking so many questions?

          • Your comments have been more acidic than usual. Just an observation, not an attack.

        • @Tietonian, when I spoke to RF last week, he mentioned that I was getting mellow in my dotage and lamented the fact that he hadn’t been forced to “moderate” my comments lately. So I’m thinking that my pH is trending toward 7.

          As far as Pope Paul is concerned, my feeling is that if I want to know what some pseudo-clergyman with a high collar and low intelligence thinks about something, I’ll watch Al Sharpton.

          • As I don’t read the comments on every article, I suppose he would know better.

            We are in agreement on the “pseudo-clergyman” bit, but for different reasons I’m guessing.

            Any chance of you writing anymore articles for TTAG? Maybe another serial like the Daily Digests?

        • “As far as Pope Paul is concerned, my feeling is that if I want to know what some pseudo-clergyman with a high collar and low intelligence thinks about something, I’ll watch Al Sharpton.”

          We need to hang out, Ralph, because I want to buy you all the beers for that line.

    • Interesting read but entirely anecdotal. Some hard data from all over the nation, documented thoroughly would a much better read than someone saying “I prefer a .45 ACP and I’ve seen a whole lot of one-shot kills with it so that’s why I prefer it”. I suppose if your capacity is limited by bogus law, go with the biggest you can field, when it’s not a factor, does it really matter if you have to shoot more to neutralize a threat?

      • All studies of terminal ballistics on human targets in real self defense gunfights are going to be anecdotal. There is simply no way to perform that experiment in a controlled, repeatable fashion.

        Evan Marshall’s publications of real data is an interesting start. Fackler’s studies are excellent as well. Forget the horse snot ‘war’ between these two factions and take ALL data as data.

        There is more data here:

        Studying real gunfights with .45 (and any other caliber, but just to use an example) lays to rest ALL this caliber war projectile vomit stuff.

        Sometimes the pet theories are found to be true. Sometimes they are not. Remember Jared Reston found out he was in a gunfight when he got shot in the jaw by a .45, was shot an additional 6 times while he was returning fire and he lived to tell the tale.

        .45, .40, 9, .357, etc, etc have all failed; they have all succeeded.

        First rule: have a gun.

  15. If words could be considered projectiles, then anything coming out of Dianne Feinstein’s mouth.
    I love to pick on here because I spent many years in Kalifornia.

  16. The followup shot.

    The followup shot is BS. The emphasis on it is breathless nonsense. In caliber choices it seems to be deemed as a vastly more important factor than first round shot placement. People actually choose a caliber/handgun for it’s supposed ability to provide the magic followup shot.

    This is my primary reason for dismissing .40 critics. .40 critics who dismiss a full sized combat handgun in forty as ‘too snappy” yet heartily recommend a lightweight, single stack 9mm with 124 +P’s.

    You seldom hear the same crowd bagging on the 10mm, instead opting to remain is awe of it’s magnum level power.

    The same mob scoffs at revolver carriers and the .357, but in a different way. ” “How quaint” they might say with a smirk, but with the forty, they lose their minds entirely.

    The followup is BS for defensive shooters, and it’s only real usefulness is for shooting games with timers running.

    • Well, as the fly said as he crawled across the mirror “That’s one way of looking at it”

    • Huh?

      Doesn’t matter what caliber you are using, you should be training to get two well placed shots on center mass and then keep that firearm out, finger on the trigger, hopefully, pressed all the way to rear so you can get off another shot from reset, making completely sure the threat is neutralized and actually down. Keep shooting until the threat is stopped.

      What kind of Hollywood nonsense is it to tell people they should be focused on one shot?

      Good grief.

      The level of stoopid in these conversations is nothing short of amazing, as people make fools of themselves trying to defend their choice of caliber.

      This kind of thinking will get you dead, quick, fast and in a hurry.

      If you are not willing to “deploy your weapon system” with accuracy, speed and violence of action, just go sell it.

      • I’m really curious about what aspect of people who would engage in a caliber debate strike you as unserious or stupid. It seems to me that vigorous debate about anything regarding SD is a good thing as it would serve to weed out bad ideas and reinforce good ones.

        I realize you’re just a contrarian who’s stock in trade is belittling others. I suppose even pompous, misinformed misanthropes have a place in the debate.

        As for useful advice you fail:

        “Doesn’t matter what caliber you are using” a .45 has a 17% greater per shot stop average.

        ” you should be training to get two well placed shots on center mass and then keep that firearm out”
        Absolutely incorrect and dangerous, you should continue to fire on a threat until it either disappears (behind cover, has run away or is incapacitated).

        “finger on the trigger, hopefully, pressed all the way to rear so you can get off another shot from reset,”

        Again, ludicrous. What you should do is continue firing as rapidly as accuracy allows until either the threat is stopped or the weapon is empty. Any other plan defies logic and ignores a century of gun fighting experience.

        “Keep shooting until the threat is stopped.” This is the only good advice to come out of your misbegotten statement. One should continue to fire until the threat is stopped, not in two round increments but as fast as accuracy allows until the threat is stopped or ammunition is exhausted.

        I don’t know what the Hollywood rule is, but that you’ve never engaged in combat with pistols is quite obvious. Bad idea follows bad idea. Has it occurred to you that you might get someone killed by espousing garbage where good advice is needed? Do you care? Is self aggrandizement worth more than altruism?

        “This kind of thinking will get you dead, quick, fast and in a hurry.” Would have made a great title you your post, since what followed is apt to get someone killed in a DGU. I really can’t believe you’re evil and thus ignorant will have to suffice. Perhaps you’ll learn something about CQB before discussing it again.

        • Oh, well, ok, I’ll play along,

          “I’m really curious about what aspect of people who would engage in a caliber debate strike you as unserious or stupid.”

          Stupid because every single thing that can possibly be said in caliber wars has been said, many times over. Last thing we need is another caliber war discussion, but just read what I said. It should satisfy your “curiosity.”

          “a .45 has a 17% greater per shot stop average.”

          There are so many variables in this kind of assertion that it is nearly meaningless. What you seem incapable of understanding is that “stopping power” is relative, and, even to use the concept “stopping power” is misleading to begin with. The KEY is not caliber, it is accuracy and speed to time on target effectively.

          “What you should do is continue firing as rapidly as accuracy allows until either the threat is stopped or the weapon is empty. Any other plan defies logic and ignores a century of gun fighting experience.”

          Idiotic reaction, based on your apparent total ignorance of

          “Keep shooting until the threat is stopped.”

          But of course, that was not what you posted, you were obviously just trying to advocate for .40 SW with some stupid notion that it is a “one shot/one stop” type of round.

          Now you try to deflect from this nonsense.

          Oh, well, whatever.

          Enjoy your caliber wars.

  17. In answer to the OP question.

    This thread.
    I might have said “This article” but I started skipping ahead pretty early. I like my word problems kept to a single paragraph.

  18. Rember kinetic energy = mass *(velocty)^2 /2 So faster and lighter might be better. (but since energy is conserved I guess fired w/ the same powder the heavier one won’t be going too much slower)

  19. F = MV, but Mass provides more Force than Velocity.

    Here’s why: Velocity decreases rapidly during penetration, while Mass does not.

    Penetration doesn’t just occur at the point of impact; but continues to occur as the projectile continues to impact its target (considering it has thickness).

    A simple fact of physics. Why is it that nobody ever mention that these days?

    • Arg – I meant P = MV, and that Mass provides more Momentum (not Force) than Velocity, and therefore greater penetration.

      • First, one of the things I was trying to get at was, both mass and velocity apply equally to momentum. It’s a product of two numbers, so as long as proportionate changes are kept, the impact on momentum would be the same.

        Second, velocity only changes as force is applied. Force is the measure of work, so the more work done, the more force applied. Additionally, force is also known as the change in momentum. In both cases (Light/fast or slow/heavy) if the same work is done, which means the same ammount of tearing, the same change in momentum should occur, and the velocities should work out to magically be at points where momentum is the same. This is, of course, assuming that mass doesn’t change, and that two projectiles of equal dimension (not mass of course) perform the same ammount of work.

        It’s not actually magic, but meh.

    • No body talks about it because it’s inconvenient. For many the 9mm must be superior and any calculation that indicates differently must be erroneous. Just as mass is immutable the concept of initial and maximum diameter escapes some 9mm aficionados. Bear with it, like most aberrations it will eventually fade away.

  20. This is in response to RJ Re: 9mm Vs .45 in absolute performance.

    The most powerful commercially available 9mm loading is from Grizzle ammo with a 90 grain slug moving 1625fps and turning in 528ftlbs of energy. This round is a phenom and quite out of the ordinary for a 9mm. If you use this round you’re getting close to mid range .45ACP ballistics. .45ACP ballistics in commercial loadings top out with the RBCD Ammunition offering that drives a 90grain projectile 2036ft per second for 881 ftlbs of energy. Yes, that really is an energy gain on par with simply using a standard .45 and adding a standard 9mm hit to it. It’s so much more energy that the 9mm doesn’t even compare, especially since it necessarily always comes in a narrower diameter bullet.

    This theme repeats across more likely loadings, the .45 can be cooked to far more powerful loadings than the 9mm is capable of. As I’ve said before, chemistry and physics are immutable no matter now badly you wish it weren’t so. 9mms are great guns, but they are not and cannot ever be as powerful as .45acps. Not so long as physics matters.

    So, in conclusion, there are reasons to use 40 and 45, and no, with no ammunition conceivable, let alone commercially available is the 9mm as powerful as either a 40 or a 45. Isn’t, cannot be, wont be, physically impossible and proven by math. Just stop with the 9mm is as powerful as a .45 forever because it is forever a fallacy.

    If you like 9s, awesome, it’s a great cartridge that performs well in SD situations with appropriate ammunition. However it’s not as capable as a 40, which isn’t as capable as a .45, and none of them can do what a .44mag does (really, it’s hideous what the difference is).

    Just because you really like your 9 doesn’t alter physics and mathematics. Do a little research, learn a little something, and don’t just insist that it is the way you wish it was.
    This was a pretty good try, best there can be, since anyone who did research would realize that the .45 is ballistically superior to the 9mm and stop arguing before they posted.

    • So, you seriously don’t think that James Yeager and Chris Costa have researched 40 and 45? Why do those two guys serve our country with 9mm and train all of their students with 9mm then?

      I stupidly bought a 40 and a 45 last year but sold them and switched to 9mm. I get a lot more capacity and faster followup shots, with more rounds downrange. Also, when I take my G19 to James’ classes this summer, I’ll be able to run it longer since 9mm doesn’t need to be cleaned as often.

  21. Look the solution to all this debate is simple. Get a MAC-10. All you have to do is aim at the knees, and pull the trigger one time. Recoil and muzzle climb will take care of the rest. The muzzle will likely be aimed at his head when the magazine runs dry.


  22. Now I am going to open up a serious can of worms.

    ” … when the claim is made that light and fast is, due to physics, not capable of performing as well as slow and heavy, regarding penetration and reaching vitals you have projectile vomit. This quite simply can’t be true.”

    Au contraire mon ami. If the response of the target medium is dependent on the impact velocity of the projectile, then fast-and-light may indeed penetrate better or worse than slow-and-heavy with the same momentum. Research “non-Newtonion” liquids such as a cornstarch solution. Push your hand slowly into a cornstarch solution and you penetrate all you want. But try and punch or smack the cornstarch solution with a high velocity blow and the cornstarch stops your hand at the surface. To what extent body tissues have such properties I do not know.

    A more important factor: how does the body respond to a light-and-fast versus a heavy-and-slow impact? I am not sure. It wouldn’t surprise me at all that our central nervous system responds with much greater intensity to certain impact speeds than others. Keep in mind that the greater the response of an attacker’s central nervous system, the higher the probability of stopping your attacker.

    I would love to see someone research those two important aspects of terminal ballistics. I have a strong inclination that there will be an optimum impact speed and weight for stopping an attacker.

    • I think you’re onto something. I’ve proposed that a possible explanation as to why the empirical data suggests when force is equal, a slower, heavier slug tends to produce faster stops (fewer rounds fired) than a lighter, faster slug has something to do with perception of the impact/wounding mechanisms.

      You’ve just suggested a possible explanation for the mechanism behind my explanation. This is why I love TTAG.

  23. By the basic momentum equation p=m*v (p is momentum, m is mass, and v is velocity), the 9mm HST has about 75% of the momentum of the .223 round mentioned. Interesting stuff.

  24. OK, here’s a way to put all this debate to rest.

    Go to Africa. Someplace that has Cape Buffalo and brush. You’re going to need an outfitter or guide.

    Or hunt large dangerous game here in the US with an outfitter – something like grizzly or moose.

    Tell them you’re going to use a .22-250 AI, pushing a 50gr pill at over 4,000 fps instead of a more commonly used rifle round – eg, something flinging a bullet heavier than 200 grains, better closer to 300 (or more) grains.

    See what the outfitters think of your idea. See how much longer you’re going to be a client of your outfitter when you insist that sectional density doesn’t mean anything.

    Or ask people in Alaskan brown bear country what they prefer for defense against brown bears. Here, I’ll tell you, because I have: 12 gauge shotguns with slugs, about 500 to 700+ grains of lead in a tidy package.

    Let’s get back to mass vs. velocity in a more abstract, but meaningful way: Let’s look at both ends of the spectrum of mass vs. velocity trade-off.

    Too much of the ballistics discourse on TTAG involves pistol calibers and DGU’s. All commonly used defensive pistol calibers have spotty performance where “one shot stops” are required. Real world results show the efficacy of large masses, even at slower speeds, and the real world I’m talking about is the world where we’re taking on something that will cause you to die from Hobbesian brute force, not some criminal intent.

    Let’s take two extreme examples to finish proving the efficacy of mass vs. velocity.

    Toss a railroad locomotive worth of mass at someone at, oh, 100 feet per second. This is absurdly slow for a projectile, much slower than even the velocities out of primitive weapons like bows, slingshots, etc.

    100 feet per second, by the way, is about 68 miles per hour – faster than most freight trains move. Do many people survive being hit by a train at even 50 MPH? Nope. Not even when they’re surrounded by an auto body or even a truck frame. Mass wins. Would a grizzly or cape buff survive getting whacked by a locomotive at 100 feet per second? No. They’d just be a bigger mess on the tracks, that’s all. There are films on Youtube of cows, deer, moose, et al, as well as Class 8 trucks, being hit by trains. The train barely even notices hitting a cow. I’ve seen a cow hit by a coal train moving at, oh, 40MPH. Cow goes flying through the air in a graceful arc, landing as a mashed-up leather bag of dead cow. Mass did that, not velocity, and that’s because when you study kinetic collisions between two bodies, you find out through application of physics that in a collision, the heavier body in the collision “wins.”

    Let’s take the other extreme as an example: A neutron discharged from radioactive decay. Let’s not worry about the exact velocity, as it will depend upon the particular radioactive decay involved. Instead, let’s just agree that it is very fast.

    Does the nearly insignificant mass of the neutron affect its ability to penetrate? Not at all. It is moving at such a velocity that it will go through you – or dangerous game. Through and through. Will it cause damage on the way through? Yes, but not enough to make a human, much less dangerous game, even notice the passage of a single neutron through the body. Unless you have a large number of neutrons creating such a huge combined disruption of body tissues, the ability of neutrons to pass clear through a body individually doesn’t matter, and their high energy, which is almost entirely attributable to their high velocities, is of little importance. Does the human punched through-and-through by the neutron even notice the penetration? Probably not. Unless you pile on the neutron flux to a level where it causes cellular disruption on a level that will cause organ failure or nervous system disruption, the human being punched through-and-through by the neutrons will not be stopped from moving.

    Given these two ends of the mass vs. velocity argument, which results would you prefer? Those of a cow being hit by a locomotive, or a neutron passing through a mammal?

    I use heavy bullets because I prefer the results from heavy masses, even at low speeds, and I never can seem to get a locomotive to follow me around where I need it most.

    • Uh, just some napkin math going at the moment, but It seems like your example is a bit skewed in favor of the train.

      Due to the difference in mass, the neutron would have to be travelling a few times faster than the speed of light to have similar momentum. At which point I belive comic books teach me the world explodes.

      Also the biggest part of that argument is your whoopsy-ing stress for velocity. If the object is smaller it requires a much reduced ammount of force to defeat the tensile strength of an object. So of course a neutron will penetrate, it’s 1amu or 1.6726×10^-27 kg. It takes virtually no force to pass through an object. Force is a measure of work that can be done, so no force means no work. An example of work would be tearing apart a vital organ. Instead, the neutron will pass through the object nicely.

      Better example. Train vs 30mm GAU-8 Avenger 30MM .395 kg projectile. Train comes in at about 680000kg going 30.48m/s yet still the “Small” 30MM projectile going 1,070m/s is going to do some massive damage. Imagine what would happen if you increased the velocity in this case to the similar difference that you see in mass. .395kg projectile going 58.5 million m/s


      • I chose the neutron example deliberately, since so much emphasis in DGU ballistics is now based on penetration. OK, neutrons from radioactive decay penetrate clear through tissue, a couple blocks of ballistics gel and quite possibly even a concrete wall or two behind the initial target body. I’d say we’ve got the penetration angle covered there. And their velocity is about as high as we’re going to see before we start to violate physical laws. Their mass is so slight that the “recoil” that one would feel from firing a neutron mass, even at those velocities would be nothing. Oh, and you could fit a whole lot of them into even a single-stack magazine. Ta-da! The ideal DGU pistol, right?

        As you point out, of course you cannot match the momentum of a train with a neutron. That’s exactly my point. There comes a tipping point in ballistics where one finds that the road travelled by Roy Weatherby is a dead end – probably about 4,500 fps or thereabouts. That’s the highest muzzle velocity that one can get from even light bullets before you start seeing jacket failure from rotational forces on some bullet designs. Maybe the new solid copper bullets would provide a bullet that could be pushed to higher velocities, but due to limitations on chamber pressures (about 70 kPSI) before case failure, there’s a real limit to how fast we can accelerate a bullet in the typical 24″ of barrel length.

        There’s a reason why hunters of large and/or dangerous game learn to prefer mass over velocity. A .22-250 is going to make a real mess for the hunter of Cape Buffalo, whereas if he went afield with an ancient Four Bore, he’s probably going to do OK. Things like the Four Bore didn’t come about because someone said “Hey, let’s see how many guys can handle this!”

        No, the Four Bore came about because Cape Buffalo and elephants didn’t simply crumple and fold when hit with an Eight Bore, and shooting them with smaller rifle rounds proved to be not only ineffective at stopping a charge, but an exercise in inciting problems.

        re: the GAU-8. Most of the effectiveness of the GAU-8 comes from the exploding or pyrophoric projectiles it uses. They also maximize projectile mass by using DU, instead of copper-jacketed lead. If they were using projectiles of a design similar to what we see in the .50 BMG ball rounds, they’d be more effective than the .50, but nothing like what the GAU-8 is known for today. DU projectiles sort of prove my point: Even when the designers had an awesome rate of fire available to them, they also chose to maximize projectile mass, which increases sectional density (remember sectional density? It was supposed to be projectile vomit, according to the OP).

        Taking the DU issue one step further, look at kinetic energy anti-tank/anti-armor rounds now in common use in tank sabot rounds. DU is again used to maximize mass, as well as to provide pyrophoric properties. When the sabots fall away, leaving a long, skinny but heavy DU dart, you’ve got a very high SD indeed, which is required to penetrate armor plate.

        • Again you’re comparing oranges to turnips. The more mass and velocity you turn out, the better you do. The more force you have, and the more force for the same area means more stress, and therefore a greater ability to damage. Remember when I said Fast/heavy would be ideal?

          With DU rounds, they get velocity. They shoot those rounds so fast, that the easiest next improvement is mass. But take it in a senario where velocity isn’t a given. Would it be a good idea to use DU rounds in a .45, buping the mass to about 386gr yet trying to stay in safe pressure ranges? As a thought experiment only, and ignoring anything but the mass increase.

          When you compare the .22-250 to the 4 bore, you are again comparing something with massive mass and a still high velocity to something with insignificant mass and not a high enough increase in velocity to bridge the gap. So again, counter example.

          Which would you rather: 1800gr 4 bore at 1330fps or a .50BMG at 1/3 the mass (600gr) and just over 2x the velocity (3080fps)?

          And again clarifying, I’m not saying fast/light is good or slow/heavy is bad, rather that it has almost become institutionalized to ignore half the equation. Which cuts out a potential avenue of reasearch and ballistic study. While also teaching people to scream “But physics!” when they ignore half of the physics.

        • On a charging dangerous animal? I’ll take the 4 bore, in a double rifle.

    • I prefer to go with observed results over theoretical, when the observed results can be properly obtained and properly observed. I appreciate where Dyspeptic Gunsmith is coming from with a heaviest & slowest vs. lightest-and-fastest object in the universe comparison, but I think it’s a lot easier to create a simply-observable result.

      I approached this question from a perhaps more practical aspect, which is — how do we compare the damage of the lightest and fastest projectile I can reasonably get, vs. the heaviest and (accordingly) slowest projectile that I can get, that will BOTH deliver the SAME kinetic energy to the target?

      Accordingly, I used a rifle with the smallest, high-velocity round I had in my stash, a .22LR with an Aguila SuperMaximum. It’s a 30-grain hollowpoint, rated on their website at 1700 fps, although I don’t know what kind of barrel they used to get that number; from my rifle it delivered 1457 feet per second. Being a hollowpoint, it would be more likely to expand quickly and slow down faster, thus (to use the vernacular I hate) “depositing more of its energy in the target”.

      I shot a chicken with that .22LR, and it made a nasty wound, blew a 2″ wide hole in the chicken and shredded the shoulder bone it passed through. At 1457 feet per second and 30 grains, that represented about 140 foot/lbs of kinetic energy.

      For the slow & heavy, I then used a 14-pound bowling ball, and dropped it onto the chicken from a 10-foot height. At impact, the bowling ball was traveling at about 25 feet per second, delivering approximately 140 foot/lbs of kinetic energy.

      The amount of damage delivered to the target is not the same. 🙂

      As a final thought experiment, I leave you with this — you can throw a pebble a whole lot faster than you can throw a heavier rock. If someone with a knife was charging you and your only hope of defense was to reach down and grab either a pebble or a rock to throw at the attacker, which would you choose?

      • First, love the videos, I’ve watched all of the 9mm ammo quest so far. One of my few subs.

        In every example I’ve seen where two objects present with the same potential energy (Kinetic energy is a measure of work done, potential energy is a measure of work that can be done), but different work is done, there is a usually obvious reason.

        In the chicken example, the .22 shows the true peril of over penetration, that is, not having the ability to do the work it has the potential for. While using a HP helps, and allows for the .22 to do more work than a standard projectile, in the end, it obviously can’t do all the work it’s potential energy allows as there’s nothing to act on. This is why frangible varmint rounds exist. To allow for the most energy transfer possible on such a small target with such low resistances.

        The bowling ball doesn’t have that issue because of it’s diameter. It creates more compressive stress than sheer stress preventing the penetration, but causing an anvil-esque effect. Good for smooshing chickens, but not something so impressive that the military will switch their sidearms for bowling balls.

        However, it does show the varying effectiveness of different types of energy delivery methods (HP vs FMJ vs JSP vs Jacketed frangible) and the trade off between ability to penetrate vs ability to do work.

        As to the final thought experiment. I’d point out that a gun fires what is essentially a small fast rock. Delving a little deeper. Why do you assume that the pebble goes as fast, let alone faster, than the rock? Is it likely that a professional baseball pitcher will throw a baseball slower than they could throw one of those plastic ball pit balls?

        This really is an interesting topic. Honestly at this point, while I hope I’m right, I wouldn’t be sad to learn that I’m wrong.

  25. “To allow for the most energy transfer possible on such a small target with such low resistances.”

    Granted there are bullets that are designed to transfer the most energy possible. But energy transfer isn’t the same thing as wounding, and there are many cases where much LESS energy transfer results in MUCH MORE devastating wounding.

    Energy is the ability to perform work, but as we say in business, you shouldn’t confuse “activity” with “progress”.

    Simple example — a baseball, thrown by a pro, can reach 100mph, and if it slams into a player it will “deposit” 100% of its energy into that player’s body. At 5 oz, that’s 105 ft/lbs of energy deposited direclty into the player’s body. Yet we see this happen frequently, and usually there is no permanent damage at all. Maybe some bruising, maybe in the worst case a cracked rib, but that’s it. Now take the example of a .22LR bullet fired from a handgun, at the same player. At impact it’ll have 100 ft/lbs of energy, but if aimed at the heart, it will likely penetrate clean through, puncture the heart, and result in the player’s death. Same energy, different work done, different results.

    Or, here’s a hopefully more graspable example — let’s use 12-gauge shotgun loads. A shotgun loaded with an ounce of #8.5 birdshot fires that ounce of lead at 1,240 feet per second, and that payload contains 1,495 ft/lbs of kinetic energy. The pellets aren’t going to spread out very far in a potential home defense scenario, so let’s presume that every one of those pellets hits your target — that will result in the target absorbing 1,495 ft/lbs of energy. None of the pellets miss, and none will overpenetrate, so the end total entirety of the energy transferred to the human invader is 1,495 ft/lbs of energy.

    Alternatively, you could have loaded that shotgun with a 1 oz Brenneke slug. Exactly the same payload weight, exactly the same velocity, and exactly the same potential impact energy. But, the slug is going to destroy the target — a 12 gauge slug is one of the deadliest projectiles a human could be hit with. And, furthermore, the slug is going to “waste” much of its energy on overpenetration. A 12-gauge Brenneke slug should penetrate 27″ of gel. If we consider a human torso to be 11″ deep, the Brenneke would still be going over 632 fps when it exits — meaning it will retain 388 ft/lbs of energy after it’s exited the body. That energy would be “wasted”, since it’s potential available energy that was not put to work to damage tissue — but … does it matter? Hardly. The slug will have blasted a huge hole clean through the target and shredded bones and organs and everything else in its way, while using 1100 ft/lbs of energy to do it. The birdshot will have used all 1495 ft/lbs, and will have created a nasty shallow wound, but the odds are that the birdshot wound will be a lot more survivable than the slug wound would be.

    “Why do you assume that the pebble goes as fast, let alone faster, than the rock?”

    I don’t assume; I went out and tested it with my chronograph. 🙂 Threw a 670-grain rock, and a 2600-grain rock, both river rock of comparable density and overall shape. I was consistently significantly faster with the 670-grainer than I was with the 2600-grainer.

    “Is it likely that a professional baseball pitcher will throw a baseball slower than they could throw one of those plastic ball pit balls?”

    Of course not, but that’s not relevant to my example, because the density of the pebble and the rock are the same in my example. A baseball is a lot more dense than a plastic pit ball.

    But let’s limit it to a more reasonable comparison — a 1 oz rock, vs. an 8 oz rock. If we assume that your arm is an engine capable of delivering a certain maximum amount of thrust to be applied to the rock, which will be the more devastating projectile? I mean, it’s a silly question, we all know the answer — we’re going to throw the heavier rock.

    In ballistics terms, I’m basing it on this: If you apply an equal amount of force to propel an equally-dense object, the lighter object will be propelled faster than the heavier object. At an equivalent PSI rating of 35,000 PSI and using a SAAMI test barrel, the SAAMI specifications state that a 9mm cartridge will propel an 88-grain .355″ diameter lead “pebble” at 1,500 feet per second, and that same cartridge at that same PSI will propel a 147-grain .355″ diameter lead “rock” at 985 feet per second.

    Interestingly, the 88-grainer has a lot higher kinetic energy (440 ft/lbs) than the 147-grainer does (317 ft/lbs) but I know which projectile I’d trust more to get the job done. Just like if I had to throw a rock, I don’t care how fast I could throw that little rock, I want to use the big rock because I know it will do more damage.

    • Thank you for taking the time to respond I am enjoying this. I hope it’s not grating or frustrating for you.

      A couple things: Energy transfer is a terrible term that I try to avoid as much as possible for this very reason. It confuses what actually happens. I used the word “work” a lot in my first response to you, because that’s what matters. The goal is to do work on the target. Specifically work on the parts that allow the target to keep doing what you don’t want them to. Disrupt those vital parts, and you stop the action. An applied example would be self-defense. Lethal threat comes in, projectile does work on a part of the central nervious system, and lethal threat is stopped.

      Potential energy is useless if it isn’t converted into meaningful work, and not all potential energy is “Converted” to work. The baseball example is a very good example, and a good parallel to the light/fast slow/heavy discussion. The baseball actually doesn’t do all the work that it’s potential energy allows. It sounds counter-intuitive because once it lands it has no more potential energy, but it’s true. Good example is to find a solid wall that you’ll never be able to dent, break, or knock over, and attempt to do just that. Try and go straight through the wall until you’re so tired you can’t move. You’ve done 0 work on that wall. Open a door an you’ve done more work on that door than you have on the wall. -That’s- the example of activity vs progress in pure physics.

      In the bowlingball vs .22 example, there was only so much chicken that the diameter of the .22 could interact with, meaning it couldnt do as much work. With the baseball vs .22, it was a matter of tensile/compressive/torsional strength. The baseball couldn’t defeat the strength of the target, and was unable to provide any meaningful deformation meaning very little work actually done. Due to the smaller diameter of the .22, the round was able to apply more stress, overcome the strength of the target, and provide meaningful deformation.

      That’s why I consider “9mm is all you need, all modern bullet’s perform the same” type comments as projectile vomit as well. Ammunition is a series of trade offs. Bigger diameter means more ability to interact with a target, and more work done on the target, with the disadvantage of having less efficient work, and thus a more difficult time of penetration. It’s also why I feel jacketed frangible rounds, like DRT ammo, may possibly be viable self-defense rounds, but that would take a little more research before I’d put them over the 147gr HST’s you and TNoutdoors made me a fan of. There’s definitely potential in that design though.

      My whole point with the article is that velocity is almost ignored when making ballistic considerations. I wasn’t speaking of caliber like 9mm vs .45. Rather, simply touching on some of the more basic physics whoopsies that become ballistic gospel somehow. Mass is the only part of momentum. Penetration is dependant on mass per area not force per area, and the measure of force per area is somehow equal to the measure of mass per area. That type of comment, which is sadly commonplace, is the type of thing I think needs to be turned from. I also wanted to hear some of the funniest caliber related claims.

  26. “That’s why I consider “9mm is all you need, all modern bullet’s perform the same” type comments as projectile vomit as well. ”

    That type of talk is utter nonsense, I totally agree. There’s a picture that goes around that shows all the calibers penetrating equally, which tends to be used to support that argument, but it drives me a bit batty because it doesn’t take into account two very fundamental things:

    1. The total amount of crushed tissue is much greater with a larger bullet, and
    2. Sometimes bullets DON’T expand. And when that happens. a .45 that doesn’t expand will destroy a full 50% more tissue than a 9mm will.

    I agree that velocity is important, but I don’t agree that you can get equivalent performance by just pushing a smaller bullet faster. It may sound good in a textbook, and it may look good for Liberty to show “the world’s fastest handgun ammunition”, and it may look impressive that one round shows a higher KE figure than another round does, but when it comes to coroners and autopsies and surgeons and hunters, that question has been thoroughly researched and is already settled.

    You hit the nail squarely on the head when you said that in the debate between “light/fast” and “slow/heavy”, that the ultimate winner would be “fast & heavy”. That, however, usually isn’t a choice we get unless we’re using a rifle (and a main reason why I adore the FAL, AR10, and .308, and why my RJM with a 300-grain bullet at 1700 fps is one of my favorite handguns). Drawback, of course, is all those weapons are huge, have much higher recoil, and the ammo is huge and heavy… there’s always tradeoffs.

    Then there are other considerations that don’t get talked about much, but should. Such as that tiny little bullets are far more susceptible to “course changes” and deflection than larger bullets are. A big heavy bullet is much more likely to stay on course and hit what you aim at. A little bullet can be thrown off course a lot easier. I have shot a tremendous amount of bullets into tissue simulants and I can say that it is far, far, far, far more common to see .22’s and .380’s veer off course, than it is to see .40’s and .45’s veer off course. And that’s without bones in the mix; add a bone in there and you increase the likelihood of deflection, but the lightweight bullets are vastly more likely to be deflected than the heavy bullets are.

    “It’s also why I feel jacketed frangible rounds, like DRT ammo, may possibly be viable self-defense rounds”. Having tested DRT, and Liberty, and G2 RIP, I can say that they all do have the potential to be a viable self defense round… and they all have the potential to be a complete failure as a self defense round. And for those reasons, I would never, ever want to RELY on that type of bullet construction. They MAY work, and they may work great when they do work. A DRT or RIP to the throat would be almost certainly incapacitating or fatal. But if you hit any intervening object, or your target is obese, then there’s a very high chance that those rounds will fail to do any substantial incapacitating work on the target at all. The RIP might still get some work done because it has a 49-grain solid base, but the Liberty’s base is a thin disc of only 26 grains, and the DRT has no substantial base at all.

    If you hit a hog on a side shot in the ribs with a DRT or Liberty, it’s probably going to prove quite effective. If you hit a human from the side, and the bullet has to go through his arm or shoulder first, the DRT or Liberty or RIP trocars are going to separate and dissipate pretty much entirely within the arm, leaving very little to continue on towards the vital organs. Even the best of the bunch, the RIP, results in a relatively tiny little bullet that’s about the size of, and half the weight of, a .380 FMJ. Compared to a (relatively) gigantic HST at nearly an inch in diameter and 3x the weight, there’s simply no question as to which has the more potential to incapacitate, and to do so through more situations, more conditions, on a wider variety of potential targets.

    If you haven’t had a chance to read it, I highly, highly recommend the book “Bullet Penetration” by Duncan MacPherson. He’s a physicist, a rocket scientist and ballistics expert, and he explains very thoroughly and in depth about velocity, energy, the physics of collisions, and the particular aspects that involve and revolve around collisions involving bullets and flesh. It’s not an easy book to get ahold of, but I would think someone of your obvious math background might really appreciate it.

    • Thanks for the recomendation, I’ll look for that.

      I’m not a fan of liberty, or RIP ammo due to the projectile designs. DRT and ammo of similar design looks potentially promising due to the jacket that prevents fragmentation for the first portion of the bullet’s entry. I have, in person, seen deer taken with ammo ranging from .243 to 30-06, and the videos I’ve seen of deer being cleaned after being shot with a 39gr and 55gr DRT suprised me greatly.

      I won’t say it was equivilant, because that would be a lie. One deer taken with a .270 lost it’s entire ribcage and had most of it’s organs and blood on the ground. Cleaning was very easy in that case. What did stand out about the DRT, was the ability to penetrate the ribs or shoulder of a deer, cause massive damage in the case of the shoulder hit(destroying the bone and causing massive muscle damage), while still fragmenting and tearing the heart apart, damaging lungs, and disrupting other organs like the liver. I had initially expected the fragmentation to be captured by a deer’s shoulder, but that didn’t end up being the case.

      Due to the demonstrated ability of the .223 to defeat the muscle and bone of a deer shoulder, if the handgun DRT type ammunition shows similar penetrative ability prior to expansion, it should win in every senario where it gets a shot to the torso, head, or really any uninterrupted shot, while also being able to defeat intermediate inorganic barriers. (sorry long sentence, really long) If it can defeat those outer defenses, it’s expansion allows for more potential tissue crush.

      It’s main trade-off seems to be the inability to defeat the incredibly powerful “Forearm” Barrier. There seems to be two camps regarding this issue. The “who cares” camp and the “I care” camp. I’m not quite sure which camp I’m part of. It could be potent self-defense ammo, or it could just be relegated to impressive sporting ammunition.

      Suffice it to say, I’m not ready to jump on it’s bandwagon quite yet, but I’m also not ready to lump it with G2’s stuff. The RIP’s almost immediate expansion is counter productive to the “Radically invasive” intent. It would be a slightly different story if they intended to market it as an interesting novelty round, but as it is, and as they try to make it seem, it’s really an unmitigated falure.

      As to DRT, the “timer” created by jacket separation seems to allow for enough penetration, prior to expansion, to defeat most biological barriers prior to expansion. Depending on the handgun caliber’s ability to do the same and the lack of ability when it comes to passing through undesired biological barriers in between the shooter and target (Meaning an arm in the way) there may just be too many hurdles to overcome.

      However it is an interesting design and there may just be some potential in that design direction. In my opinion at least.

Comments are closed.