The myth/ truth of "WASTED ENERGY"

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  • Vanguard.45

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    On many of the gun forums, whenever a discussion of sufficient penetration of bullets vs. the overpenetration of bullets on a body arises, I often see posts similar to the following:

    "The bullet is transferring a tremendous amount of energy into the target as it decelerates in the body. For me over penetration is considered wasted energy since the bullets energy is not competely transferred into the target."


    One camp, reflected in the quote above, seems to believe that a bullet which penetrates deeply, but not through and through, somehow "dumps" more energy into a body since the round stops before exiting.

    The other camp, the one to which I tend to subscribe, believes that a bullet which blows through a target tends to dump lots of energy all the way through the target and also leaves another hole through which more blood/ air might leak out of the goblin.

    So, in your opinion, which is it? Does the 44 Magnum tend to transfer more energy to a target during a "through and through" than a .45ACP coming to rest in the body? Or, does the deceleration of the round somehow contribute to some sort of "energy dump" due to the round coming to a stop?

    My opinion is that the 44 Magnum ripping through a person would tend to send a shockwave through them from front to back and would continue to have energy emitting from it as it continued on its merry way past the target! Yes, the 44magnum has more energy to give to targets past your primary one, but isn't a through and through the epitome of the maximum transfer of energy to that primary target resulting in the round continuing to destroy tissue all the way through???

    I am not here to address the issue of environmental considerations (i.e. bystanders hit by overpenetrating bullets) in this discussion, because, of course, one must consider this in choosing a defensive handgun. However, I am simply wanting to talk about the myth/ truth of this idea of "wasted" energy or bullets coming to rest in the body somehow "dumping" more energy into the body because they have come to rest.

    What are your thoughts? If you are being charged by a 300 lb. goblin and have the .45 in one hand and the 44 Magnum in the other, which do you feel confident would do more to slow him down/ dump more energy into him?

    Vanguard.45
     

    DeadeyeChrista'sdad

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    I'd be happy with either. That said, I belong to the through and through camp, and do consider over penetration to be not my problem if things are already bad enough that I have to squeeze the trigger. I don't mean to sound reckless, but I definitely want two holes in my bad guys.
     

    Bigtanker

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    My uneducated opinion.

    Bullet "energy" is kinda like stopping power. Doesn't matter. As long as it penetrates deep enough into the target, hitting vital things, it has enough energy.

    More a little later when I have time.
     

    BigBoxaJunk

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    I don't think I'll ever stop worrying more about being able to have my bullets hit where I want them to than to worry about what they do when they get there.

    But most here on INGO are probably much better shots then I am.
     

    BehindBlueI's

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    "Energy dump" is BS and is not creating any sort of "extra" wounding in most tissue. In terms of handgun rounds, temporary stretch cavity is just that, temporary, and is like you pinching your skin and lifting it up. It moved, it deformed for a bit, but then it just snapped back and left no sign.

    In short, you're asking the wrong question. It's very much like stating car #1 has 350 ft/lb of torque, car #2 has 500 ft/lb of torque, who wins the drag race? You can't tell with just the "energy" and no other information. Equally, you can't tell which bullet is more damaging based on "energy" numbers, let alone some notion it "dumps" energy into tissue and damages it.

    To steal from DocGKR:

    Physics. Its real. Kinetic energy is simply a measure of the work potential of a projectile. As noted above, although part of the equation, kinetic energy in and of itself it is not a predictor of incapacitation effectiveness. Recall:

    -- Bullets cannot physically knock down a person by the force of their impact.
    -- Kinetic energy or momentum transfer from a projectile to tissue is not a wounding mechanism.
    -- The amount of "energy" deposited or momentum transferred to a body by a projectile is not directly proportional to the amount of tissue damage and is not a measure of wounding power.
    -- Wounds of vastly differing severity can be inflicted by bullets with identical kinetic energy and momentum.

    What a bullet does inside the body--whether it yaws, deforms, or fragments, how deeply it penetrates, and what tissue it passes through is what determines wound severity, not KE!

    Your absolutely ideal bullet would penetrate completely through your target then immediately stop. There is no benefit, from a wounding perspective, to leaving the bullet in the body. The flip side is most of the bleeding does stay inside the body, it doesn't gush out. An extra hole on the back isn't twice as much bleeding.
     

    snapping turtle

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    When trying to get a rem 700 classic in 17 rem to shoot well. (Had 17 caliber chatter tooling marks in rifling) the idea was just in the first range of thought. Save the hides one hole in pelt. On fox and coyotes it did seem to plant well hit ones right in the tracks. In on one side and not out the opposite side. Massive bullet expansion also. I would say that when dealing with very small calibers traveling very fast the all energy expended into the animal seemed to work very well. The rifle had horrid copper fouling would shoot great for 7-10 shoots then you would have to clean clean clean out the copper. Wisdom might say that a 22-250 could do so on a wolf size animal. Maybe the 25-06 on say a pronghorn ect.

    The 222 rem I have never found the prefect one hole in loading for coyotes not to mention a smaller fox. Aside from a few shot that have hit high around the spine seldom have the coyotes drop on the spot like the 17 rem but the round is no where as explosive or quickly expanding as the 17. Normal for the 222 are through shots a jump a small run and a roll when they pile up.

    Now in self defense never really though about it. Pull trigger until threat is eleminated.
     

    LarryC

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    Beyond Blue Eyes said it well. The fact a bullet travels through a body has little bearing on the damage it really causes. IE: The .223 / 5.56 round is a classic example. If the bullet is not tumbling, has a small diameter and traveling below the speed of sound, it may cause very little tissue / organ damage, if it stays in or exits the body. That is why they designed the bullet to tumble. However a high speed rifle can cause a great deal of damage due to the "shock wave" generated by the bullet even without tumbling or expanding. Another issue is the proper expansion of hollow point and other hunting / self protection cartridges. These are normally designed to do great damage by expanding so that a larger diameter wound cavity is created causing greater tissue damage and bleeding. So bullet design, diameter, velocity, expansion all enter into the equation, most of these are far more important than whether the bullet exits or remains in the body.
     

    oldpink

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    The idea of hydrostatic shock with conventional handgun rounds (the above cited .44 Magnum) is a moot point because of the relatively low velocity of bullets from such rounds.
    Compared to centerfire rifle bullets moving along in the 2500fps or above range, handgun bullets are slowpokes, so they depend almost entirely upon the crush cavity created by the mechanical displacement of tissues from the expanding bullet passing through them.
    Since you mentioned the theoretical advantage of .44 Magnum over .45 ACP, you might be interested to know that the statistics indicate the best .45 ACP loads rate very near the top (90%+) range for one-shot stops, while I'm not aware of any .44 Magnum round that gets much beyond the 85% one-shot stop statistic.
     

    NIFT

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    BehindBlueI's got it right, and the OP is very short on knowledge of terminal ballistics.

    Knock-down power is a myth.
    Stopping power, synonym to knock-down power, likewise, is a myth.
    Hydrostatic shock is a myth. Hydro means water, and static means at rest or constant motion. Regardless, anything that smacks of ballistic pressure waves has been proven nonsense.
    Kinetic Energy is a mathematical construct and is not a wounding mechanism. On top of that, kinetic energy is a lousy proxy for wounding. More kinetic energy can, easily be associated with reduced wounding, and increases wounding is, often, associated with lower kinetic energy.
     
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    JAL

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    "Energy dump" is BS and is not creating any sort of "extra" wounding in most tissue. In terms of handgun rounds, temporary stretch cavity is just that, temporary, and is like you pinching your skin and lifting it up. It moved, it deformed for a bit, but then it just snapped back and left no sign.

    In short, you're asking the wrong question. It's very much like stating car #1 has 350 ft/lb of torque, car #2 has 500 ft/lb of torque, who wins the drag race? You can't tell with just the "energy" and no other information. Equally, you can't tell which bullet is more damaging based on "energy" numbers, let alone some notion it "dumps" energy into tissue and damages it.

    Your absolutely ideal bullet would penetrate completely through your target then immediately stop. There is no benefit, from a wounding perspective, to leaving the bullet in the body. The flip side is most of the bleeding does stay inside the body, it doesn't gush out. An extra hole on the back isn't twice as much bleeding.

    This is why I concern myself more with shot placement with a good JHP than whether I'm using a .380 ACP, 9mm parabellum, .45 ACP, .45 Colt, or a .357 magnum. My favorite handguns are the 1911 .45 ACP 230 grain and .357 magnum 158 grain but the smaller 9mm (124 grain) and .380 ACP (90 grain) will do just fine. The .45 Colt with 225 grain Hornady LEVERevolution JHP is growing on me even though it's a single action wheel gun.

    OTOH, at 4-7 yards, a 12 gauge with 2-3/4 inch #4 buckshot anywhere in the thorax should end it. One shot. Immediately. Approximately two magazines of .22LR fired all at once . . . plus the wad as a bonus.

    John
     

    oldpink

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    This is why I concern myself more with shot placement with a good JHP than whether I'm using a .380 ACP, 9mm parabellum, .45 ACP, .45 Colt, or a .357 magnum. My favorite handguns are the 1911 .45 ACP 230 grain and .357 magnum 158 grain but the smaller 9mm (124 grain) and .380 ACP (90 grain) will do just fine. The .45 Colt with 225 grain Hornady LEVERevolution JHP is growing on me even though it's a single action wheel gun.

    OTOH, at 4-7 yards, a 12 gauge with 2-3/4 inch #4 buckshot anywhere in the thorax should end it. One shot. Immediately. Approximately two magazines of .22LR fired all at once . . . plus the wad as a bonus.

    John

    Up close (20 yards or less with a full choke), 12 gauge with one of the various sizes of buck remains the most decisive one-shot stopper of them all, but shot placement is still paramount, as you rightly state.
     

    randyb

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    The energy you feel in the recoil of the gun shooting the bullet, is the same amount of energy from the bullet. At handgun velocity the 'stopping power' is determined by the amount of tissue destroyed by the path of the bullet. So shot placement, bullet construction, and number of rounds placed into the target have much more effect than energy. As a hunter I have found two holes better than one in how far a deer travels before falling. I prefer an in and out. Handgun rounds and what damage they do is like comparing a Honda accord going 40 mph vs a ford focus going 45 mph and arguing how much more damage they do compared to the 'rifle round' of a corvette travelling at 110 mph or a 'shotgun' 18 wheeler travelling at 50 mph.
     

    HoughMade

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    My uneducated opinion.

    Bullet "energy" is kinda like stopping power. Doesn't matter. As long as it penetrates deep enough into the target, hitting vital things, it has enough energy.

    More a little later when I have time.

    With low velocity projectiles like almost all pistols and some old school rifles (45/79 for instance), I believe this is exactly correct.

    With high velocity rifle projectiles when we are talking about appreciable hydrostatic shock in addition to penetrating and physically hitting and cutting vitals, there may be some "lost energy" if all of the energy is not spent imparting hydrostatic shock to the tissue.

    in other words, I'm not so sure it matters that much except for maybe​ in the most extreme of circumstances.
     

    two70

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    On many of the gun forums, whenever a discussion of sufficient penetration of bullets vs. the overpenetration of bullets on a body arises, I often see posts similar to the following:

    "The bullet is transferring a tremendous amount of energy into the target as it decelerates in the body. For me over penetration is considered wasted energy since the bullets energy is not competely transferred into the target."


    One camp, reflected in the quote above, seems to believe that a bullet which penetrates deeply, but not through and through, somehow "dumps" more energy into a body since the round stops before exiting.

    The other camp, the one to which I tend to subscribe, believes that a bullet which blows through a target tends to dump lots of energy all the way through the target and also leaves another hole through which more blood/ air might leak out of the goblin.

    So, in your opinion, which is it? Does the 44 Magnum tend to transfer more energy to a target during a "through and through" than a .45ACP coming to rest in the body? Or, does the deceleration of the round somehow contribute to some sort of "energy dump" due to the round coming to a stop?

    My opinion is that the 44 Magnum ripping through a person would tend to send a shockwave through them from front to back and would continue to have energy emitting from it as it continued on its merry way past the target! Yes, the 44magnum has more energy to give to targets past your primary one, but isn't a through and through the epitome of the maximum transfer of energy to that primary target resulting in the round continuing to destroy tissue all the way through???

    I am not here to address the issue of environmental considerations (i.e. bystanders hit by overpenetrating bullets) in this discussion, because, of course, one must consider this in choosing a defensive handgun. However, I am simply wanting to talk about the myth/ truth of this idea of "wasted" energy or bullets coming to rest in the body somehow "dumping" more energy into the body because they have come to rest.

    What are your thoughts? If you are being charged by a 300 lb. goblin and have the .45 in one hand and the 44 Magnum in the other, which do you feel confident would do more to slow him down/ dump more energy into him?

    Vanguard.45

    BBI and others nailed it but to elaborate further, given the same caliber with the same energy the bullet that stays in the target will have transmitted more energy to the target than the one the exits, however, with handgun rounds the total energy is low to begin with and the difference in the energy transmitted to the target between the two bullets is marginal. With rifles the energy transfer difference would be much greater but even then, for most purposes a second hole in the target is more beneficial than more energy transfer. IRC, a bullet needs to be traveling at around 2200 fps, depending on bullet diameter(with smaller diameter increasing the necessary velocity and vice versa) before energy transfer has any appreciable effect.
     

    rhino

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    A big problem is that too many people who use the word "energy" don't know what it means either in a practical sense or from a physics/engineering standpoint. As BBI mentioned in his quote, energy is simply the ability to due work. In terms of mechanical kinetic energy, it's a just a concept until it actually does the work or it transforms into another form of energy. When a bullet hits something, a substantial amount of the energy is lost as heat and does no useful work. Kinetic energy is only conserved in elastic collisions (which is actually related to the definition of an elastic collision), which don't exist except on paper (although collisions of atoms and subatomic particles can come really close to being perfectly elastic).

    I do not imply that kinetic energy is not vitally important in this situation. It is, because the amount of kinetic energy possessed by the projectile is the absolute maximum amount of work that can be done to penetrate and damage tissues. How that works gets done is the rub. Hint: it's about the tissues doing work to decrease the momentum of the projectile.

    If we want to discuss this in a consistent manner, we stop using the word energy and instead should be talking about momentum and impulse, which is the transfer of momentum. When you fire a gun, you do not feel the kinetic energy of the bullet (and gases). In fact, the kinetic energy of the gun (if it's allowed to move freely) is not equal to the combined kinetic energy of the bullet and the gases. When you fire a gun, you feel the transfer of momentum (impulse) from the bullet and gasses moving one way and the gun moving in the opposite direction in reaction to the motion of the bullet/gases. The gun transfers momentum to your hands/body. Your body then reacts by moving as well. And your body transfers momentum to the Earth.

    Wounding mechanisms are very complicated because human tissues are a complicated, heterogeneous medium when considering a body.
     
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    Vanguard.45

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    BBI and others nailed it but to elaborate further, given the same caliber with the same energy the bullet that stays in the target will have transmitted more energy to the target than the one the exits, . . . .

    This is exactly the sentiment with which I disagree.

    How is "transmitted energy" expressed on tissue? It is expressed by causing damage to it. A bullet that plows through the entirety of the body has transmitted energy all the way through the body, whereas the bullet that stops in the body stops precisely because it has run out of energy to transmit. When it stops, it is no longer transmitting energy and no longer causing damage.

    Now if you want to say a bullet that stops in the body has transmitted A GREATER PERCENTAGE OF ITS ENERGY (as in 100% of its energy), then that makes sense, but the bullet that keeps on driving through past where the other one stopped is transmitting more energy (and causing more damage to the target).
     

    two70

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    This is exactly the sentiment with which I disagree.

    How is "transmitted energy" expressed on tissue? It is expressed by causing damage to it. A bullet that plows through the entirety of the body has transmitted energy all the way through the body, whereas the bullet that stops in the body stops precisely because it has run out of energy to transmit. When it stops, it is no longer transmitting energy and no longer causing damage.

    Now if you want to say a bullet that stops in the body has transmitted A GREATER PERCENTAGE OF ITS ENERGY (as in 100% of its energy), then that makes sense, but the bullet that keeps on driving through past where the other one stopped is transmitting more energy (and causing more damage to the target).

    As I stated in my previous post, I'm assuming same caliber and same energy for both bullets. As you rightly point out the bullet that stops in the tissue has run out of energy to transmit. The corollary is that he bullet that penetrates completely has not and continues on transmitting energy outside of the side tissue until it comes to a stop. Since the assumption is that both bullets started with the same energy, the one that quits moving in the tissue will have transmitted more energy to the tissue while the other bullet transmitted a portion of its energy outside of the tissue. It is faulty to assume that energy transmitted equates damage, especially with handgun rounds for the reason already explained by BBI and others.
     

    BehindBlueI's

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    How is "transmitted energy" expressed on tissue? It is expressed by causing damage to it.

    The engineers can explain it better than me, but that's not correct. Energy transfer and work are different things.

    Transferred energy can be accomplished in several ways, but what's being discussed in wound ballistics as "energy transfer" is talking about the stretch cavity. Kinetic energy is transferred to elastic energy*. As Rhino pointed out, kinetic to heat energy is another type of transfer energy, but not one we look at in terms of wounding.

    Human tissue has a certain elasticity it will accept without injury. I think we've covered it, but if you pinch your skin and pull, your skin will stretch but will return to it's original shape without damage until you exceed its tolerance. So you can transfer energy as both heat and elastic energy without causing any damage. That's your "shockwave" from your original post. At handgun levels, it's not relevant to wounding except in certain organs with low elasticity limits.

    *I may not be getting the terms correct from an engineering/physics standpoint. You're turning motion of the bullet into motion of the surrounding non-crushed tissue which stretches and then returns as a result.
     
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    First my thoughts are, what is beyond the target that would also be destroyed.
    My second thought is, I think about that idiot lying on the operating table having the doctor digging the bullet out.
    Then having the damage being sewed up.
     

    WanderingSol07

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    Take any bullet and shoot it through a body. The body should absorb X amount of energy no matter how fast the bullet is going and how far it goes after leaving the body. The optimal amount of energy would get the bullet just out of the body on the far side (exit). Any more and energy is wasted on the bullet going on.

    Of course we always want enough energy so the bullet goes through no matter what it encounters on its travel, soft tissue, bone, Iphone, or clothing. So more than enough seems logical.

    Does hollow point fragmentation (more holes after being hit, but smaller than original bullet size) work better than a single slug because you have multiple chances of hitting something vital? How far does a hollow point go into tissue before fragmenting?
     
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