The hydrostatic shock theory?

[Odd Job]

JohnKSa says

I have neither the resources nor the inclination to attempt to verify his results given that I'm not at all certain there's much of a way to turn the results into something practical in terms of handgun stopping power. I saw his experimentation and theory primarily as expanding the understanding of terminal ballistics by providing explanations for effects that are fairly commonly observed but not well-explained by other theories of stopping power.

I understand.

Vern says

If we did that (examine the brain of a gun shot deer for evidence of hydrostatic shock) we'd end all debate and gun forums would wither and die.

We still got 9mm vs .45 and also birdshot for home defense

 

[Pasteur]

The experiment has been performed shooting deer in the chest and inspecting the head for vascular damage.

In the present study, vascular damage was observed in the brain that was visible to the unaided eye and that resulted from a remote ballistic impact to the thorax in human-sized animals.

Here, qualitative results are reported for a small field study that isolated a thoracic mechanism for TBI caused by a high strain rate insult in white-tailed deer (Odocoileus virginianus, mass 49-80 kg) in a natural environment. In each of three cases, petechiae were present on the surface of the frontal, occipital and/or left parietal lobes, along with capillary damage in the choroid plexus. The location of the projectile impact to the thorax seemed to affect the degree of damage. This may be due to the proximity to the great vessels. The data reported here provides direct evidence of a thoracic mechanism resulting in gross injury to the cerebral vasculature.

See:
Cerebrovascular injury caused by a high strain rate insult in the thorax. Amy Courtney, Michael Courtney. Cornell University Library. Medical Physics. 2011. arXiv:1105.4738v1

Another interesting 2011 paper reviewing the evidence:

History and evidence regarding hydrostatic shock. Michael Courtney, Amy Courtney. Neurosurgery. February 2011 - Volume 68 - Issue 2 - pp E596-E597.

A myth is an assertion which has either been disproven by careful experiment or for which there is no historical or scientific evidence in cases where it is reasonably expected. Belief in remote effects of penetrating projectiles may have originated with hunters and soldiers, but their reality is now well established in a broad body of scientific literature...

 

[Vern Humphrey]

MRIs are often used in autopsies. It "may" tell enough and it's not as messy

I checked. Mountain View Custom Butchery doesn't have an MRI.

 

[Mike1234567]

I checked. Mountain View Custom Butchery doesn't have an MRI.

LOL!! I'm sure they don't. But "research" facilities do when it fits their needs.

 

[Odd Job]

Pasteur says

Here, qualitative results are reported for a small field study that isolated a thoracic mechanism for TBI caused by a high strain rate insult in white-tailed deer (Odocoileus virginianus, mass 49-80 kg) in a natural environment. In each of three cases, petechiae were present on the surface of the frontal, occipital and/or left parietal lobes, along with capillary damage in the choroid plexus. The location of the projectile impact to the thorax seemed to affect the degree of damage. This may be due to the proximity to the great vessels. The data reported here provides direct evidence of a thoracic mechanism resulting in gross injury to the cerebral vasculature.

Thanks for providing that, Michael Courtney (I know you are traveling incognito, but you and I both know that it is well known who "Pasteur" is)

If what you have reported is true and if the experiments were conducted with integrity and the appropriate veterinary input also, let me be the first to publically state:

Michael Courtney has proved that there is a direct link between gunshot injuries to the thoraces of deer, and findings of cerebro-vascular damage in those deer. That means there must be a ballistic pressure wave.

I am simultaneously astounded that you have waited so long to do it, yet stepped forward and done it nevertheless.

EDIT: it would have been nice to have a control deer taken by arrow, from the same population, and nice also to have these tests done with handgun projectiles matching your original PSI requirement, but nonetheless this is significant and a step in the right direction.
Who did the necropsy?

 

[Loosedhorse]

That means there must be a ballistic pressure wave.

I am simultaneously astounded that you have waited so long to do it, yet stepped forward and done it nevertheless.

Why are you not "astounded" at yourself for not having "stepped forward" and referenced this study? If we're going to criticize someone for showing up "late" with pertinent info, then we should criticize everyone else for not knowing about it. It wasn't hidden.

I'd prefer just to thank Pasteur: thanks! The study is here.

We already knew that there was a ballistic pressure wave, before the mentioning of this study. We already knew that sometimes deer collapse at the moment they're hit. What this study shows is the consistent (over just three animals) finding of grossly visible small vessel injury in the CNS in deer taking thoracic hits with a .257 rifle bullet.

What we don't know is still a lot. Why was the pattern of vascular damage different in each animal? How did each animals behave after being shot--did one collapse immediately, or run and plow its head right into a tree? Is the CNS vascular injury attributable ONLY to the bullet? What relationship does such injury have to supposed BSW-medated collapse? What would happen with a handgun round? Should we assume that similar cerebrovascular injury happen in humans?

Just trying to keep track of (and differentiate among) what we know we know, what we think we know, and what we know we don't know.

 

[Vern Humphrey]

LOL!! I'm sure they don't. But "research" facilities do when it fits their needs.

The closest research facility is at Toad Suck Ferry.

 

[MachIVshooter]

We already knew that there was a ballistic pressure wave, before the mentioning of this study. We already knew that sometimes deer collapse at the moment they're hit. What this study shows is the consistent (over just three animals) finding of grossly visible small vessel injury in the CNS in deer taking thoracic hits with a .257 rifle bullet.

What we don't know is still a lot. Why was the pattern of vascular damage different in each animal? How did each animals behave after being shot--did one collapse immediately, or run and plow its heads right into a tree? Is the CNS vascular injury attributable ONLY to the bullet? What relationship does such injury have to supposed BSW-medated collapse? What would happen with a handgun round? Should we assume that similar cerebrovascular injury happen in humans?

Well, I definitely agree with you here.

One question: Was the study only three animals, or were there more and "in each of three cases" refers to three out of however many where the hemorrhaging was present? I went to the site provided, and that information is not available. Can we access the rest of the study?

Your best point is that we don't know how the animals reacted, and so don't know if the BPW (not argued) causing hemorrhaging (contested) causes immediate or extrememly rapid incapacitation (widely doubted).

Additionally, since it was "in their natural environemt" and therefore lacking controls, how do we know that, as you said, the deer didn't plow into something and cause the injury that way? And if not, how do we know that it was BPW and not extreme blood pressure that was the result of an adrenaline response to the trauma that caused the vessels to rupture? Since adrenaline not only increases heartrate and BP, but is also a vasoconstrictor, how do we rule out it's effects on these animals?

Perhaps a stretch here, but could it even have been that these three deer were bucks during the rut, and the injuries were caused by smashing their heads together prior to being shot?

I've said before and I'll say again that I don't personally and haven't seen anyone else question the presence of the BPW, but what it's effects are. I really don't think the testing in a natural environment can prove that it was the BPW that caused the petechiae. Can't rule out other possibilities without a more controlled experiment.

 

[Odd Job]

LoosedHorse asks

Why are you not "astounded" at yourself for not having "stepped forward" and referenced this study? If we're going to criticize someone for showing up "late" with pertinent info, then we should criticize everyone else for not knowing about it. It wasn't hidden.

Well I didn't see it, it's as simple as that. Evidently, neither did you or you would have posted it yourself way before we got to page 8 of this thread.

MachIVShooter asks

Additionally, since it was "in their natural environemt" and therefore lacking controls, how do we know that, as you said, the deer didn't plow into something and cause the injury that way?

Controls would have been nice, yes. And some timing for when they dropped. The cherry on top would have been a number of handgun-shot deer with cerebral flags, and one or two controls shot with arrows and no flags.
Nonetheless he is on the right track now, can't be too churlish about it. It's a small sample, but that is tangible evidence if the proviso in my previous post is met.

 

[JohnKSa]

So show us how it's done.

The paper shows how to do the calculations you are interested in and you can find information about force, energy, momentum and their relationships all over the web.

Courtney's theory is flawed...

No and no. No, it's not "Courtney's theory". No, it's not flawed.

The real problem is that you have some sort of mental block about kinetic energy. I honestly think that you believe someone invented it, and the equations that deal with it, just to screw with people who are trying to understand terminal ballistics--in order to make things confusing and misleading. It's simply not true, and until you get past that issue you're not going to make any progress in the direction of understanding the basics of projectile physics.

 

[MachIVshooter]

The real problem is that you have some sort of mental block about kinetic energy. I honestly think that you believe someone invented it, and the equations that deal with it, just to screw with people who are trying to understand terminal ballistics--in order to make things confusing and misleading. It's simply not true, and until you get past that issue you're not going to make any progress in the direction of understanding the basics of projectile physics.

Kinetic energy was one of the fisrt things I understood about ballistics, and for a long time when I was younger, I placed too much importance on it.

As we all know, there is a lot more to terminal ballistics than energy. And if you were to dig through my posts deep enough, you'll find that I have emphasized before that KE is a good measure of the ability to do work. I've said more than once and almost verbatim that a higher KE allows a bullet to be either driven deeper, expanded wider or a combination of the two.

This concept does not elude me.

However, back to the 100 ft/lbs in .02 ft:

Quoted from the site you linked for the equations:

Even though the application of conservation of energy to a falling object allows us to predict its impact velocity and kinetic energy, we cannot predict its impact force without knowing how far it travels after impact.

Just as I said, we cannot know the force if we don't know the time (or velocity). We have distance and KE, but we need time (or velocity from which to calculate time) since force is a product of time, distance and mass or, more simply, acceleration (or deceleration) and mass.

That site also does not show us how to calculate the force applied by an energy exerting object that travels a certain distance but does not stop in that distance. I'll be content if you can solve for it as I mentioned earlier, or if you can point me to somewhere where I can, because I've been looking and had no success in coming up with any formula other than the one I derived using another for conservation of energy.

Until then, I maintain that using the standard force=time/distance*mass tells us that a bullet that deposits that energy in less time will produce greater force. Hence the 9mm round that depostis 100 ft/lbs over .02 ft in 17 microseconds exerts greater force on the target than the .45 ACP that deposits the same 100 ft/lbs in 26 Microseconds.

Noteworthy is that the difference in force between the 9mm and .45 loads is proportionate to the difference in momentum (after the energy loss).

I'm all ears for whoever can explain how something else mitigates the difference in force I came up with when the energy transfer occurs in the same distance over different times. I'm not being a smart@$$; I really would like to know if there's something I didn't factor in that will show both of those loads to produce 5,000 pounds of force, regardless of their different velocities and resulting different amount of time spent in the target delivering the energy.

It did strike me as quite a coincidence that the velocity loss of each was so close to shed 100 ft/lbs, though I didn't plan it that way; I just picked two common, standard loads.

No and no. No, it's not "Courtney's theory". No, it's not flawed.

So creating examples with inelastic collisions is only flawed if I do it?

 

[JohnKSa]

The website says:

we cannot predict its impact force without knowing how far it travels after impact.

But, of course we can if we DO know how far it travels after impact.

So with kinetic energy and penetration (how far it travels after impact) you can calculate impact force.

We have distance and KE,

Penetration distance and KE is enough. I gave you the equation, Courtney uses it, I gave you a link to a website that explains it.

So creating examples with inelastic collisions is only flawed if I do it?

Courtney's examples do not make any unjustified assumptions.

Your examples assumed that all the energy of the projectile was turned into acceleration of the target. That doesn't happen in the real world and therefore it's not surprising that your numbers appear to be unrealistic. (Assuming the calculations are correct--I'm not going to check them because whether they're correct or not the assumptions you've made will mean that your interpretation of the results will be totally unrealistic and therefore confusing to you.)

force is a product of time, distance and mass or, more simply, acceleration (or deceleration) and mass.

Kinetic energy is also a function of time, distance and mass, and can be expressed in terms of acceleration and/or deceleration as well. I gave you the relationships in an earlier post and if you don't believe me you can verify them elsewhere on the internet.

The units of Force are mass x distance / time / time
Mass, distance and time

The units of Kinetic energy are mass x (distance / time) x (distance / time)
Also mass distance and time

If you divide the units of Kinetic energy by distance you have the same units as Force.

Or, said another way, if you multiply the units of Force times distance you have teh same units as Kinetic energy.

KE = F x D

F = KE / D

http://www.school-for-champions.com/science/work_energy.htm
"Work is force times distance
The definition of work is that it equals force times the distance traveled while that force is being applied or

W = Fd"

"Work is kinetic energy"

http://hyperphysics.phy-astr.gsu.edu/hbase/work.html
"Average impact force x distance traveled = change in kinetic energy"

http://galileo.phys.virginia.edu/classes/109N/lectures/momentum.html
"work = force x distance"

http://www.ftexploring.com/energy/PE-to-KE.html
"Kinetic energy was converted to mechanical work (force acting through a distance"

http://www.lightandmatter.com/html_books/lm/ch13/ch13.html
"W = Fd"
"The change in kinetic energy associated with the motion of an object's center of mass is related to the total force acting on it and to the distance traveled by its center of mass "

http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/forces/kineticenergyrev1.shtml
"work done (joule, J) = force (newton, N) × distance (metre, m)"

http://www.livephysics.com/tools/cl...ated-to-impact-force-from-falling-object.html

"Average impact force x Distance traveled = Change in kinetic energy"

 

[MachIVshooter]

Yeah, nevermind. While you were writing that, I went back over my figures and reminded myself why you don't do that stuff when you're exhausted.

I made a couple of errors in bullet velocities because I didn't write them down, and that accounts for the discrepancies I had. It all adds up now.

This bit of confusion stems from never trying to equate pound force with bullets, because I was never trying to accelerate an object I was shooting at, so the number seems relatively useless. And it really is, since you can't quantify what that pound force becomes after impact. There is no breakdown for what percentage of it will expand a bullet, what percentage will damage the target, what percentage will move the target, etc., so it's purely academic.

The reason I questioned Courtney's figure with such ferocity is that, being someone who has a great deal of experience with applied force in my occupation and who has fired hundreds of thousands of rounds over the years, it seemed erroneous that something like a bullet could generate such force, yet barely be able to move something like a block of wood weighing only a few pounds. And honestly, it still doesn't seem right when we consider that a .22 LR can produce ~140 ft/lbs and stop only an inch or so (making ~1,650 pound force) into a bowling pin that weighs maybe 3 1/2 pounds, yet cannot drive that pin off of a table. I know that force is used up somewhere, but I'm sure most would agree that it seems something making enough force to accelerate a 1,650 pound mass to 32 FPS in one second should be able to move that damn pin off the table!

It would be interesting if we could find a sensitive enough accelerometer to attach to said bowling pin and see what it's accelertion is during the few microseconds the bullet is applying the force.

Thank you, though, for those sites. They'll be useful in the future, because the long hand of this stuff takes forever and, as I proved and ended up with egg on my face, leaves room for error.

 

[winfried]

Energy is the key to damage, momentum to the weapon

Hi all, I do not have the time to read all this, but I spent my time working with the problem.
Have a look at the pictures, pressure is indicated by the "blow-out" near the wound channel.

Mechanical damage as well as hydro shock can be observed far from the bullet path.

Kinetic energy is the potential t o do damage, the deposited energy is an indicator of the damage.

As far a force (or power some of us will call it), a .223 will penetrate 100 to 150mm typically in a gelatine block causing much damage without penetration. A similar .22 bullet of much lower velocity will penetrate the gelatine block with ease. For those who understand, no explanation is needed, for those who do not understand, no explanation is possible.

One more thing, gelatine tests giving a comparable performance for different bullets, but are never an indication what will happen in a body.

Regards

 

[Mike1234567]

Nice post, winfried. Do you have more visuals? A picture is worth a 1000 words when trying to explain and prove something.

 

[MachIVshooter]

Mechanical damage as well as hydro shock can be observed far from the bullet path.

It most certainly can, and none of that is in question. We know that bullets passing through flesh create damage both by contacting the tissue directly and by creating pressure that in turn creates a cavity, and the damage caused by the cavity is a result of the tissue's ability or inability to stretch that far. Small temporary cavity in elastic tissue=a little bruising, while large temporary cavity through inelastic tissue=horrific damage.

However.......this thread is about the remote effects or lack thereof with a ballistic pressure wave that propagates through the vascular system in a living creature and, as much fun as shooting chunks of meat is, it tells us nothing of those effects.

Mr. Courtney is hell-bent on proving that a ballistic pressure wave can cause remote cerebrovascular damage that accelerates incapacitation, but there is a great deal of distance between finding small vascular hemorrhages in the brains of some deer shot with high velocity rifle bullets in an uncontrolled field experiment and proving that a service caliber handgun can cause neurological incapacitiation of a human with remote BPW.

I believe (and I think the general concensus at this point concurs) that 1)it is going to be exceedingly difficult to isolate the effects of the BPW from all the other effects of being shot in a place where the BPW is close enough to a major vessel to even be a factor and 2) That the effect or lack of effect the BPW has really isn't going to change the fact that service caliber handgun effectiveness is dependent on penetration and shot placement.

As was pointed out earlier:

Let's take hydrostatic shock theory first. In order to generate the most possible hydrostatic pressure in the target, you want to put the shot into areas of the body that have the most fluids, organs, etc, center of mass. That way you get enough of a pressure wave to travel through the bloodstream, damage the brain, and incapacitate the target.

Now for the internal bleeding/organ failure theory. You want to put your shot in the areas of the body to do enough damage to the internal organs as possible, in order to cause bleeding severe and rapid enough that the target loses the ability to function and is thusly incapacitated.

So in short, if you believe in the hydrostatic shock theory, you aim center of mass.

And if you don't believe in the hydrostatic shock theory... you aim center of mass.

 

[PowerG]

That pretty well sums it up, MachIV. Common sense would indicate there could be effects from the pressure wave, but there is a big difference between the most common self-defense handgun calibers and hunting rifles, and it's obvious that many shootings have taken place where the shock presupposed by proponents of that have obviously had little or no effect on the bad guys. So for me, I'll put more trust in COM bullet placement, and if the shock wave ends the encounter faster, so much the better...but I know for a fact that permanent cavities through vital organs tend to work rather well.

 

[rhodco]

Gee, with all the physicists and scientists in this one gun forum we should be able to solve all the world's problems now.

All I know about this subject is what I saw when shooting a metal newspaper vending machine we found in the woods. My 9mm 124gr +P Speer JHP @ 1200fps made an impressive dimple from about 11 yards away. But, my .45ACP 230gr FMJ @810fps punched all the way through from the same distance. Several times from different angles we proved to ourselves that the .45ACP was doing much more damage with each shot than the 9mm could.

Now I know what to use if I'm ever attacked by a metal newspaper box.

 

[SN13]

I'd imagine that "Hydrostatic shock" happens at different velocities for different calibers.

Because bigger bullets displace more tissue per inch of penetration, so the tissue would have to move faster to get out of the way for two bullets of different caliber but identical speed.

 

[JohnKSa]

I would like to publicly apologize to MachIVshooter for treating him less than respectfully on this thread.

Clearly he has a strong interest in this topic and equally obviously he's willing to spend time and effort learning about the physics and mathematics involved, all of which is commendable.

It was wrong of me to respond harshly instead of taking the opportunity to be more constructive in how I addressed his comments. I will do better in the future.

That the effect or lack of effect the BPW has really isn't going to change the fact that service caliber handgun effectiveness is dependent on penetration and shot placement.

I think this is a reasonable statement. At this point it seems that BPW might provide a way to shade the odds a bit in one's favor by choosing calibers that the Courtney's research/calculations indicate create BPW magnitudes sufficient to have a good chance of causing significant neurological effects.

Assuming, of course, that such a choice doesn't result in tradeoffs that are unacceptable or unwise for a particular shooter.

In other words, pick something out of the service pistol/self-defense caliber class with adequate penetration, that you can shoot well, load it with premium self-defense expanding ammunition, aim for the center of mass and shoot as many times as it takes to cause cessation of hostilities. Sound familiar?

I do not intend that statement to belittle or dismiss the research and experimentation the Courtneys have done. I believe their research is helpful because it explains effects that are commonly observed but not well-explained and because it expands our knowledge and understanding of terminal ballistics. I look forward to more research and experimentation on this topic as I hope the entire firearm community does.

There is certainly a lot that we still don't understand about terminal ballistics and it's unfortunate that there are strong and well-respected voices in the established community of terminal ballistics researchers that seem to be willing to speak out scathingly against anything that disagrees in the slightest respect with their pet theories and published ideas regardless of whether or not it seems to have a good basis in fact & science. We need to be careful to balance our skepticism with a level of open-mindedness that allows us to at least examine and evaluate new ideas objectively as opposed to dismissing them out of hand as some are wont to do.

 

[Panzercat]

Is this thread still going on?

 

[winfried]

Hi, a 14 year old boy had driving a tractor when a .22 rifle discharged accidently. The bullet graced the neck only. All important blood vessels were missed.
The boy was stitched up and kept for three days observation. He was sent home but died 4 days later. Autopsy showed that microscopic bleeding in part of the brain, as the result of hydro shock was the cause of death.

Furthermore you people have the most complete study of woundballistics in the Library of Congrees. The book is called

 

[winfried]

Sorry, the book is called WOUND BALLISTICS by Maj Beyer. To produce this book today, would probably cost US$ 20 Million. In it every aspect under discussionhere is dealt with.

Pressure waves, damage of nerves far from wound channel, broken bones as a result of a bullet passing nearby.

Furthermore when somebody talks about shot placement and center of mass, how do you define center of mass? If you mean the upper torso, there is not much chance of disabling somebody. Any shot below the lungs will be instantly disabling.

Regards

 

[winfried]

I agree with the statement that researchers often do have a pet theory and fail to look right or left. Also for the researcher who knows, he can prove today one fact and tomorrow the opposite fact without being dishonest.
For instance, it is easy to prove that a .223 bullet (soft point or FMJ makes no difference) will penetrate at least 10mm mild steel plate. By making a different arrangment the .223 will only pnetrate 3mm mild steel.
Or a 8gram 9mm FMJ fired from a 3" 357 will not realy make a dent, but a small mark on a 10mm steel plate. Then with different arrangement the latter bullet will penetrate 8mm of mild steel.
How is that for confusion? Easy to prove by anyone.
However, reading other peoples research papers, observing autopsies and filling the gap with own research, there is not really a mystery to wound ballistics.
In the USA there are two problems, one is the imperial system in use and the other is the nonsense brought about by the 1904 Thompson Lagarde tests, then quoted wrongly by somebody and then Hatcher developing the idiotic RSP formulae, which is easy to understand but as wrong as can be.

Regards

 

[winfried]

"About 03h we received a radio message that a bushman tracker had returned to one of the camps with a chest shot from an AK and wuld be brought into Runtu hospital by helicopter. On notification that the patient had arrived and was in theater, we found him standing there smoking a cigarette with his rifle over the shoulder. He had a wound on the left chest in front and in the back. We took x-rays and found indeed that it was through and through wound. We cleaned and closed the wound and kept him for a week in case an infection would come to pass. This did not happen, but during that time we found out, that the bushman was wounded early morning the previous day. He tracked the terrorist during the day for about 12 hours. He said he could have shot his prey a few times during the day, but he wanted to shoot him in the abdomen so that his opponent would die painfully and slowly. Just before sundown he could get his shot placed and then walked back another eight hours back to base."