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Part I: "Energy Dumping" Is A Myth

Let me state right here and now that there are two terms you're going to hear that have no meaning. If you haven't heard them yet, you will, if you spend any time at all on a shooting range or hanging around the wiseacres in gun shops. Both refer to popular myths among shooters about how a bullet kills, and are based on thorough misunderstanding of ballisitics and biology.

"Hydrostatic shock" is the idea that a bullet kills by setting up a "shock wave" in the incompressible water of which an animal's body is largely composed. "Energy dumping" is the concept that if a bullet stops within an animal, it will kill more effectively than one that goes through and exits, since it "releases its entire amount of energy within the body."

As intuitively appealing as these notions are, the fact is that a bullet kills the same way any other agent of penetrating trauma does. A bullet may act faster than a knife or an arrow, but like them it kills either: 1) by causing a rapid loss of blood pressure, depriving the central nervous system of oxygen; or 2) by physically interfering with nerve pathways; or 3) both.

The False Reasoning Behind The "Energy Dumping" Fallacy

The bullet does indeed have a good deal of kinetic energy, and the faster it's moving the more it has, of course. In the USA bullet energy levels are rated in "foot-pounds", a relatively obscure unit implying the amount of energy needed to move one pound of weight one foot.

European countries use the much more sensible (in the case of this post) metric system, and in this system the energy unit is the "joule". While both these units refer to energy of movement, the joule has the advantage that it can easily be converted to units used to measure heat. One calorie is equivalent to 4.1 joules, the calorie being a unit of heat. Specifically, one calorie is the amount of heat needed to raise one gram of water one degree Celsius. (The comparable unit in the US system is the BTU (British Thermal Unit), but converting foot-pounds to BTU's is not so straightforward as converting joules to calories.)

A bullet fired from a reasonably powerful handgun, say a hot 9mm Parabellum load, has an energy level of perhaps 500 joules at the muzzle.

So why do I care about converting muzzle energy figures into heat? Because if a bullet is stopped in its target, that's exactly what happens: its residual kinetic energy is, in fact released (or, as the wiseacres have it, "dumped") into the animal's body; but it's released as heat, in accordance with the laws of thermodynamics. (This is the reason why your car's brakes heat up when you stop: that energy can't be destroyed, it can only be converted to another form, and the "defaut" is to convert it to heat.)

The amount of heat liberated by stopping a bullet is surprisingly small: 500 joules works out to be about 106 calories. That would be enough to raise 106 grams (about 0.25 pounds) of water one degree Celsius (about 1.8 degrees Fahrenheit). That's not all that much, especially when compared to the size of animal it has to be "dumped" into.

A man is a pretty large animal (about the size of a deer) and 500 joules (or 106 calories) of energy diffused through the body of a 150-pound (68,100 gram) human would not suffice to raise his body temperature even one-one-hundreth of a degree Fahrenheit. And that is a maximum amount, which assumes the bullet is stopped and that the shot was fired at point-blank range. To have a noticeable effect on tissue temperature you would have to "dump" a great deal more energy than 500 or so joules: the amount of heat liberated even by the biggest and baddest bullet available is very far below the capacity of the body's water to absorb it. It should be obvious, then, that the theory of "energy dumping" is based on an exaggerated idea of how much energy a bullet actually has, and is meaningless as a part of the killing mechanism.

Believers in the "energy dumping" theory never seem to have an adequate explanation for the fact that there are many, many gunshot victims are still walking around with bullets that "dumped" all their energy, and are still inside the victims. Many people with such retained bullets received them at close range from large-caliber guns, and were therefore the unlucky recipients of lots of "dumped" energy, but they are still alive. The answer, however, is really very simple: they are still alive because they were lucky enough not to have received a hit in a vital area.

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Part II: "Hydrostatic Shock" Is An Even Bigger Myth

Proponents of the "hydrostatic shock" theory usually argue that animals are composed largely of water, and therefore a bullet causes a "shock wave" to be set up in them, which causes displacement of organs, and rupture of tissues. Their belief in this concept is bolstered by the spectacular splashes that expanding bullets make when fired into plastic milk jugs filled with water: they imagine that something of the same thing happens in an animal body. They are wrong!

First, animals aren't jugs of water, and don't resemble jugs of water in the least. Animals don't have uniform internal density, and the response of muscle to a bullet is very different than that of, say, the bones or the lungs. At the microscopic level, animals are actually very compartmentalized, and there is almost no "free" water (or any other liquid) to constitute a homogeneous medium in which a "shock wave" can be propagated for more than few millimeters. About the only places where large quantities of fluids are found sloshing around are in the spleen and liver, both of which contain sizeable volumes of "loose" blood.

Second, it has been demonstrated quite conclusively that most body tissues are very tolerant of momentary deformation and quite resilient. Unless a bullet physically cuts a blood vessel or nerve, little more than localized damage is done by its passage.

It is true that in passing through, a bullet does form a so-called "temporary wound cavity" of considerable size, which lasts for milliseconds. Inside this volume a "shock wave" does form, and it even displaces some organs. But the effect of the temporary wound cavity is small, and most tissues and organs resist this very brief deformation. There is certainly no possibility--as you will frequently be told by ignorant gunshop clerks--that you can "...hit a man in the arm and the shock will travel through the blood to his brain and kill him..." Blood is carried in blood vessels, and those vessels are tough. Anyone who has dissected a freshly-dead animal will testify to the strength of an artery: it takes a good deal of force to rupture one, and physical displacement for a few milliseconds isn't enough. It's perfectly possible to displace an artery by several inches permanently with no loss of function. To do significant damage the artery has actually to be hit by the bullet, preferably by the sharp edges of the expanded outer jacket, which will cut it.

Furthermore, there is no way the "shock wave" could "travel through the blood" because the design of the system is such that a) it permits only one-way flow; and 2) it dampens pressure oscillations of considerable magnitude. Arteries that carry blood to the body are very muscular structures and designed to resist considerable heads of pressure lest they burst. And as they get smaller and smaller, ramifying to all the organs, the resistance to flow increases greatly. Even if you were to set up a significant "shock wave" locally, it wouldn't get very far in the system before the increasing resistance to its passage would dampen it out completely.

The True Believers in the "hydrostatic shock" myth often point to the messy soup found inside the chest of deer hit in the lungs as "proof" they are right. But they are really pointing to a major hole in their argument. There isn't any "free" blood in the chest of any mammal: like blood elsewhere, it's in blood vessels.

The lungs are a sort of enormous capillary bed, with millions of small blood vessels lying between the gas-exchange surfaces. Most of the volume of the chest is air. The vast quantities of blood found in the chest cavity of a lung-shot animal weren't there when the shot was fired. The free blood found in the chest after a shooting got there because the bullet damaged the blood vessels running through the area.

An expanding bullet does a fearful amount of damage to the extremely delicate tissue of the lungs, but this region also includes major blood vessels (the aorta and pulmonary artery, to name two) which are usually damaged as well. These pour enormous quantities of blood into the thoracic cavity when they're ruptured. Contraction of the body musculature and the pumping of the heart (if it too isn't hit) will assure this. The blood in the chest cavity is the result of the damage, not the cause of it, and the "shock wave" isn't propagated through it at all.
 

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a number of years ago, 2 freinds and i went elk hunting and got a small rag horn bull. one friend was using a 30-06 and I was using a 45-70. When the bull was chased into us by another hunting party, my friend fired first at about 30 yds and hit the lungs low. my shot went into almost the same hole 30 seconds later at a differentangle, but also hit the lungs. niether of us hit anything like a major artery or the heart, so when we cleaned him out, there was very little blood in the thoracic cavity. Just thought I would toss that in there.
 

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Bump to top for conversation starting info.

Peace favor your sword,
Kirk
 

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I agree that the notions of "energy dumping" and "hydrostatic shock" from bullets are mostly misguided myths.

Yes, it's partly about how much total energy is applied to a body, but it's really more about how that energy is applied. The energy in, say for example, a 124 grain 9mm slug traveling at 1000 fps, really isn't all that much. If you're wearing soft body armor and take that slug right in the chest, virtually all of its energy will be "dumped" into your torso. It'll get your attention but it won't seriously injure you. And if the hydrostatic shock thing was real, wouldn't the "shock wave" have gone right through your soft vest and turned your vital organs to jelly? But there you are, rubbing your sternum and saying "Ouch, thank God for class 3 body armor".

But if you take that same slug in the chest without the body armor, you're likely to be killed or seriously wounded. Same energy being dumped into you torso, but now it's being applied in a way that penetrates rather than hits with blunt force. This disrupts tissue much more efficiently (especially nerve and vascular tissue, so it hurts and bleeds). Adequate energy is still needed but it's really more about penetration and disruption than anything else. Bullets that whistle right through a body without expanding, often lack lethality not because they fail to "dump" their energy but because they fail to disrupt tissue despite their deep penetration.
 

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Hydrostatic shock IS real. However it usually requires energy levels in the full on hunting rifle old school battle rifle range.
 

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Isn't the permanent wound channel evidence of hydrostatic shock ?
There was a vid on here more then a year ago about shooting prairie dogs.
They would 'explode' as the little critters body is too small to contain the temporary wound channel.
I always thought that was hydrostatic shock also.
 

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Isn't the permanent wound channel evidence of hydrostatic shock ?
There was a vid on here more then a year ago about shooting prairie dogs.
They would 'explode' as the little critters body is too small to contain the temporary wound channel.
I always thought that was hydrostatic shock also.
From a hunting rifle.

Huge difference of velocity between 3,000 fps and 1,000 fps.

eldar
 

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Arrows have no where near the kinetic energy of a bullet. A bow shooting a 400 grain arrow with a 100 grain broadhead at 250 fps has KE= 69.40 ft-lbs of kinetic energy.

"Gold Tip, an arrow company, recommends a minimum of 25 ft-lbs of kinetic energy to ethically bowhunt deer. They also state 55 ft-lbs of kinetic energy would is sufficient for most popular North American game species."

The above energy calculation and quote was taken from:
http://www.wasparchery.com/blog/calculate-the-kinetic-energy-of-your-arrow

So how does an arrow kill? The answer is it kills by bleeding. Traditional archers have learned that for traditional bows (long bows & recurves), the most efficient arrowhead is a two blade razor tipped arrow that is sharp enough to shave with. Heavy arrows are better than light weight arrows in causing the razor tipped arrow to cut its way through a body. The theory is to have the arrow cut completely through the hunted animal so that the arrow goes all the way through creating both an entrance wounds (cutting through ribs) and an exit wound causing massive blood loss. Most often the arrow is found on the ground on the far side of the animal. For a deer this requires a 40 pound bow. For a man this requires only a 30 pound bow. Holly Wood movie directors have done a disservice to hunters using archery equipment in their depiction of people getting shot with an arrow and are stuck like a pin cushion with arrows that did not go completely through the body.

Why a two bladed arrowhead and not a nail point (with razor side wing blades) arrowhead? Here is an experiment I have seen on a video. The man (Paul Brunner, author and professional instinctive shooter) had a 12 inch by 12 inch thick piece of leather. He put an arrow that had a nail-point (with razor side wings blades) arrow on the ground vertically with the arrowhead tip up. Then he pressed the piece of leather on it. This nail-point arrowhead didn't cut a hole in the leather. He did that same experiment with a two bladed razor tipped arrowhead and it cut through the leather like it was butter.

Because of the low kinetic energy of an arrow, there are some that claim that hunting with bow and arrow is an inhumane way of hunting. Have you ever seen blood and wondered where it is coming from, only to discover that you yourself have a cut? Then you wonder how and when did this happen because you didn't feel any pain.

I have read that the reason you don't feel pain is that this particular type of cut was caused by something very sharp not leaving a ragged painful wound. A two bladed arrow should be sharpened with files and a wheaten stone so well that it could be used to shave hair. I have read of examples of people cutting themselves with their two bladed razor tipped arrows. I've also read of people actually accidentally getting shot with a two blade razor tipped arrow and surviving only because help was nearby. In both types of examples, the people claimed they did not realize they were cut or even that they were shot because they felt no pain. That is until they saw their own blood.

So why does a deer run when it is shot by and arrow? It runs because it has heard - a not natural sound - the twang of a bow. Even if the deer was not actually hit with the arrow, it will run because it got scared by the noise a bow makes.
 

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So why does a deer run when it is shot by and arrow? It runs because it has heard - a not natural sound - the twang of a bow. Even if the deer was not actually hit with the arrow, it will run because it got scared by the noise a bow makes.
Not necessarily true.

The second time I went bow hunting I first shot under the doe I was hunting then, the second arrow went over its back.

The doe jumped after the second shot, ran a short distance, then returned to sniff the first arrow.

The third shot was the charm. She went straight down with a heart-lung shot.

My stand was twelve feet above the ground.

eldar
 

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Hydrostatic shock IS real. However it usually requires energy levels in the full on hunting rifle old school battle rifle range.
I'm gonna amend what I said earlier - hydrostatic shock generally doesn't happen with handgun rounds (as in my example above) because there just isn't enough velocity. But I recall reading somewhere that above roughly 2000 fps (rifle territory) you do get true hydrostatic shock. So yeah, you're right and I was sorta right ;)
 

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There was a vid on here more then a year ago about shooting prairie dogs.
They would 'explode' as the little critters body is too small to contain the temporary wound channel.
Glad I wasn't drinking a Coke when I read that! :p
 

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I remember years ago, I had this shareware game called Prairie Dog Hunt Pro '97. Shooting the little buggers was a lot of fun with the .22 , but when you used the PDH5000 Laser Pistol, they burst into flames! :p
 

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So why does a deer run when it is shot by and arrow? It sometimes runs because it has heard - a not natural sound - the twang of a bow. Even if the deer was not actually hit with the arrow, it MIGHT run because it got scared by the noise a bow makes.
Not necessarily true.

The second time I went bow hunting I first shot under the doe I was hunting then, the second arrow went over its back.

The doe jumped after the second shot, ran a short distance, then returned to sniff the first arrow.
eldar
Yeah, he should have added a qualifier, as I edited his post to read.....sheesh.:rolleyes:
 

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Depends on what you are thinking about when using "energy dumping" as to whether or not it's true or false when using it.

First term you hear that is just completely made up and imaginary is "knock down power" simple physics dictates that a bullet will never ever strike something with more force than when it left the gun...if a bullet were able to take someone off their feet it would do the same to the shooter.

But when you are talking about having a bullet impart more of it's energy into a target than say a nato round that just passes through clean and straight then yes it will cause more damage which is why we have hollow point, soft core and even pre-fragmented rounds. When a round imparts it's energy into a body heat is simply a product of deformation of the round not the speed or impact being converted. It's caused by the metal rubbing itself as it's deformed, try bending a coat hanger back and forth and see what happens.

A round that deforms will cause more energy transfer and is less likely to pass through, doing so it will either multiply in size causing more internal damage as it travels through, or just flat out frag itself sending bits into even more vitals and arteries causing more bleeding and internal damage.
 

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First term you hear that is just completely made up and imaginary is "knock down power" simple physics dictates that a bullet will never ever strike something with more force than when it left the gun...if a bullet were able to take someone off their feet it would do the same to the shooter.
If you're not standing just right, "braced body" position, with the firearm firmly and properly a 30-06 or a 12GA with 3" shells can (and has) knocked down people trying to shoot them.

Lots of videos on youtube.

Basically, there can be a fair amount of energy from recoil dumped into the shooter's shoulder and if their balance isn't perfect there's a chance they can be knocked down.

Better than that, even, I can show you (live and in person) ways to "knock down" a person with just the force of your thumb (right thumb. Left one's much too powerful), by just exploiting balance points.



And I know, personally, how painful shooting some of those "real man's" guns can be on the shoulder. A antique (WWI era) army riflery manual I read spent a paragraph or so talking about how the Springfield in 30-06 can hurt some men's shoulders and basically recommends improvised shooting pads.

Peace favor your sword,
Kirk
 

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Fully aware of how bad firearms can kick, been bruised plenty over the years by rifles and shotguns.

But a few points to make, when the energy from a shot is soaked up by the shooter that is just that much less energy the round has behind it, plus a small pointy object will absolutely never ever impact anything as hard as a large flat butt. You would have to be shooting rounds the size of the butt on the gun for one to land that hard of an impact on the target.

Generally the faster a round goes the less damage it actually does like a 5.56, usually just a clean pass through. Unless you are using something so fat that it totally fragments like a .17.

Generally the slower moving ones do more damage like a slug or 30.30 round
 

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Fully aware of how bad firearms can kick, been bruised plenty over the years by rifles and shotguns.

But a few points to make, when the energy from a shot is soaked up by the shooter that is just that much less energy the round has behind it, plus a small pointy object will absolutely never ever impact anything as hard as a large flat butt. You would have to be shooting rounds the size of the butt on the gun for one to land that hard of an impact on the target.

Generally the faster a round goes the less damage it actually does like a 5.56, usually just a clean pass through. Unless you are using something so fat that it totally fragments like a .17.

Generally the slower moving ones do more damage like a slug or 30.30 round
I think maybe you oughta check your physics facts again...
 

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Fully aware of how bad firearms can kick, been bruised plenty over the years by rifles and shotguns.

But a few points to make, when the energy from a shot is soaked up by the shooter that is just that much less energy the round has behind it, plus a small pointy object will absolutely never ever impact anything as hard as a large flat butt. You would have to be shooting rounds the size of the butt on the gun for one to land that hard of an impact on the target.

Generally the faster a round goes the less damage it actually does like a 5.56, usually just a clean pass through. Unless you are using something so fat that it totally fragments like a .17.

Generally the slower moving ones do more damage like a slug or 30.30 round
Sorry, but Bull's right. In classical Newtonian Physics, at the moment it leaves the barrel, the bullet is carrying just as much energy going forward as the rifle is going backwards under recoil.

You're confusing the impedance of frontal surface area of the bullet with, umm..., I'm not sure what.

Frontal surface area of the bullet is the most important factor that causes it to dissipate energy in a medium (air, flesh, water, etc.). That's why "fatter" bullets penetrate less deeply, ceterus paribus, and why many hunting and self defense bullets are designed to expand, increasing their frontal surface area.

If not for "air drag," a bullet will impact a target with exactly the same amount of energy as was imparted to the rifle as recoil. And "fat" bullets suffer more from air drag.

Of course, there is a lot more to wounding than just that, but, aside from that fact, Bull is right; your physics are off.

Peace favor your sword,
Kirk
 

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Let's consider a model in ideal circumstances.
If a bullet passes through an object then : entry speed - exit speed = energy transferred to the object.

So if a bullet gets stuck in an object all the energy that it has remaining is transferred.
But energy transfer does not equal knock down power.
Knockdown power is kit the ability to physically 'knock' somebody off their feet.
 
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