The hydrostatic shock theory?

[Shawn Dodson]

Ballistic Pressure Wave? - http://www.firearmstactical.com/images/gymnast.mpg

Ballistic Pressure Wave? - http://www.youtube.com/watch?v=r8eK...w.m4carbine.net/showthread.php?t=34407&page=2

 

[Eb1]

All of those shots were poor shot placement on the animal IMO. The heart is lower on a pig. Also that is why you shoot a pig in the ear.

 

[JohnKSa]

The dependance of tissue types or the presence of different tissue types can hurt the theory also. In the torso the lungs won't be a good material for the propagation of a pressure wave because of air spaces in the alveoli.

That seems a logical extension of the assumptions. And it doesn't hurt the theory, it actually provides a possible explanation of why the effect isn't seen reliably even with solid torso hits. You would have to hit an area with a large blood vessel surrounded by a certain type of tissue in order to have a chance of seeing the effect. Hit an area with the right type of tissue but no large blood vessel--no significant effect. Hit an area with a large blood vessel but not enough of the right type of tissue--no significant effect.

The shot then has to be confined to the mediastinum below the level of the apex of the arch of the aorta. You may as well confine it directly to the heart and major vessel roots if that is the case.

There are a lot of very large blood vessels that run through the abdomen, and lots of fluid-filled tissues there as well.

But ANY wire couples SOME energy in an RF field.

Efficiency is not the issue here.

The ability to couple AT ALL is the issue.

No, both would be important. The question was why a torso hit would cause an effect in the brain while a neck hit didn't show a stronger effect. If the neck doesn't have the kind of tissues that couple projectile energy into blood vessels very well then that lack of coupling efficiency could mean that a hit in the neck might result in a weaker effect to the brain even though it's closer to the brain than the torso.

 

[Odd Job]

LoosedHorse says

What? Why in the world would it be surprising that ESWL produces hematuria? And why would BSW be at all simliar to ESWL.

People undergoing ESWL already have renal lithiasis: crystaline stones in the calices or ureter--good reason for hematuria already! A total of perhaps 2000 shockwaves are delivered with a total energy of perhaps 150 Joules (both figures are sometimes exceeded). That's about 110 ft-lbs, delivered to a focal volume as small as 450 cubic mm. If successful the lithotripsy breaks the calculus so that the pieces (and their sharp edges) pass through to the bladder. If slightly misaligned, the energy is not delivered to the stone, but to the adjacent renal structure.

So why shouldn't there be bleeding? Heck, there are sometimes renal hematomas after ESWL! But why should we presume ESWL is anything like BSW? My guess is if you focused ESWL enrgy at the surface of the brain, you could produce red blood cells in the CSF--but so what?

Yes, I am saying that if the ESWL can cause damage to the kidney which produces haematuria then this ballistic pressure should be able to do the same. My assertion is that the former is not surprising and the latter would not be surprising either, if it existed according the parameters of the theory.
I have assisted the urologists with the setting up of these units in theatre: unless it is an all-in-one unit, it is done by iso-centring a radio-opaque spike to the "focus" of the ESWL by means of fluoroscopy. I would do the fluorsocopy set up.
I've been in the theatre when they do this procedure and I have placed my hand in the curvature of the unit while it is operating.
If you stand there and watch the machine and the patient you can get an inkling about the likely cause of the haematuria in these cases (not pre-existing, but as a result of the procedure).
The patient has to breathe, yes? The kidneys (believe it or not) move with respiration. Even with the best gating of ESWL pulses to respiration you are going to get some unwanted damage. It's pesky details like that which seem to crop up in your mind if you have actually worked in a hospital.

One thing that ESWL does teach us about the theory of BSW? ESWL is only possible because shockwaves propagate through the human body with minimal loss of energy; that seems to be a mark against the idea that the shockwave is "dampened" as it passes through tissue.

Do you actually believe what you just posted?

(If I have perhaps misunderstood, and you mean that ESWL of gallstones routinely leads to hematuria, then I apologize for my foolishness. If I have not misunderstood, then perhaps I must pass the fool's cap along...)

You have misunderstood more than that, apology accepted.

 

[Odd Job]

JohnKSa says

That seems a logical extension of the assumptions. And it doesn't hurt the theory, it actually provides a possible explanation of why the effect isn't seen reliably even with solid torso hits. You would have to hit an area with a large blood vessel surrounded by a certain type of tissue in order to have a chance of seeing the effect. Hit an area with the right type of tissue but no large blood vessel--no significant effect. Hit an area with a large blood vessel but not enough of the right type of tissue--no significant effect.

and

There are a lot of very large blood vessels that run through the abdomen, and lots of fluid-filled tissues there as well.

Interesting musings, not part of Courtney's original theory. What tissues do you reckon are needed around these blood vessels (and by extension, where do you think people should be aiming if they want to maximise the potential for a BPW incapacitation)?

 

[Loosedhorse]

Yes, I am saying that if the ESWL can cause damage to the kidney which produces haematuria then this ballistic pressure should be able to do the same. My assertion is that the former is not surprising and the latter would not be surprising either, if it existed according the parameters of the theory

Since you used it on me: do you actually believe what you just posted?

The energy of ESWL is focused in one small spot: in EXACTLY the right place to cause hematuria, and only used in a patient who ALREADY has good reason to have hematuria even without ESWL. If you can't see how that's different from BSW, then I'm sure I can't help.

Oh, and I take it you have no evidence of routine hematuria in patients who have had ESWL for gallstones? I did ask...I guess you were just too embarrassed to answer? (I personally thought the incidence was about 5%.)

if the ESWL can cause damage to the kidney

Are you saying that it damages the kidney GENERALLY, as opposed to damaging only the tiny volume of the kidney into which the energy is focused? You have presented no reason to supposed that.

Do you actually believe what you just posted?

Of course: if the shock wave was significantly dampened in the body, then a) the renal stone could not be disrupted, because the energy would not reach it, AND b) the intervening tissue between the skin surface and the calculus woud be damaged as it absorbed the energy.

But neither of these are the case, because shock waves ARE efficiently propagated through the tissues. From Medscape:

The efficacy of ESWL lies in its ability to pulverize calculi in vivo into smaller fragments, which the body can then expulse spontaneously. Shockwaves are generated and then focused onto a point within the body. The shockwaves propagate through the body with negligible dissipation of energy...[emphasis added]

Maybe you should call them up and tell them how wrong they are?

Oh, don't worry: the fool's cap looks good on you--like you were born to wear it!

It's pesky details like that which seem to crop up in your mind if you have actually worked in a hospital.

This is the internet: why should I believe that you have worked in a hospital? Why should you believe I haven't? These appeals--believe what I say because of who I say I am? Pretty tiresome.

 

[JohnKSa]

Interesting musings, not part of Courtney's original theory.

You've characterized them properly, in my opinion, as musings.

In a sense it's extended from some of Courtney's experiments where he used water as a coupling medium to transfer BPW from the bullet to the test subject.

What tissues do you reckon are needed around these blood vessels (and by extension, where do you think people should be aiming if they want to maximise the potential for a BPW incapacitation)?

It makes sense to me that the more the situation is like a blood vessel in a bucket of water with a bullet being shot into the water, the more coupling will take place. I doubt connective tissue, bones, or even muscle couple very well; I'd guess that soft tissue like the liver, pancreas, maybe fatty tissue couple a lot better.

As far as the latter half of the question, I'd say it's premature to look at BPW in that light at this time. I don't believe it's understood well enough to recommend that people to start altering their handgun self-defense tactics in an attempt to achieve it.

The only thing I think is advisable, in light of the possibilities offered by BPW, is to use expanding ammunition in handguns as long as it doesn't unduly limit penetration. Of course that's been pretty well accepted as the prudent course of action long before anyone began discussing/debating BPW.

I'm very interested in BPW because it explains some anomalies and contradictions that turn up when the theories of stopping power put forth by the "permanent wound channel is everything" crowd are beaten against reality. But I'm less interested in it (at least at this time) as a practical method for trying to significantly improve the chances of stopping an attacker with a handgun.

 

[Shawn Dodson]

I'm very interested in BPW because it explains some anomalies and contradictions that turn up when the theories of stopping power put forth by the "permanent wound channel is everything" crowd are beaten against reality.

When "beaten against reality" there is greater evidence against BPW as a mechanism of incapacitation than evidence to support it.

 

[JohnKSa]

When "beaten against reality" there is greater evidence against BPW as a mechanism of incapacitation than evidence to support it.

Coupla things...

I think anyone who has ever hunted enough or even watched enough hunting shows has seen animals drop instantly from a shot to the body even though the bullet obviously didn't come anywhere near the components of the central nervous system. That is clearly evidence that the CNS was insulted/damaged via some means even though neither the permanent nor temporary wound channel impinged on the CNS. Does it happen all the time--nope, but it DOES happen.

Which gets to my second observation. It seems there's often confusion/obfuscation about the specific definition of what constitutes "evidence against" something. It's one thing to say that there is evidence that a particular effect isn't a consistent or dependable mechanism for incapacitation--and that's true of a number of terminal effects that unquestionably do exist. It's another thing entirely to go the extra step and say that same evidence is also evidence that the effect isn't a mechanism for incapacitation at all--yet it does not seem to be uncommon for that distinction to be blurred.

 

[tipoc]

It's unfortunate, in my opinion, that these discussions can tend to jump to the edges of what is known and move straight past what is known and observed when that is interesting enough. Some of Courtney's observations are at those edges and have little evidence to support them. I wish him luck in his studies because one way or the other they can be of value but in terms of developments in ammo I don't think that there is much there.

In the video I link to below the fellas over to Brass Fetcher have used 20% ballistic gelatin in order to enhance the visual effect. 10% is what is normally used for testing because that most closely resembles the density of human tissue. The gelatin blocks sit on 1"x1" blocks and the spaces between them are also 1"x1" or so they have told me.

http://www.youtube.com/watch?v=h23T1XS7tUo

Note what the bullet does.

You can view more here...

http://www.brassfetcher.com/index_files/Page1950.htm

In addition to the damage caused directly by the bullets passage there is also damage caused by the rapid and violent expansion of gelatin (or tissue in a mammal) as the bullet forces material out of it's way and in all directions. This action creates, violently, a temporary stretch cavity that does cause damage to tissue and bone not directly touched by the bullet. This damage and the amount of it is what the debate is about.

There is, or should be, no debate about whether damage is caused by the "wave" or "hydraulic" action, whatever one may call it, caused by the passage of the bullet to tissue not directly touched by the bullet. The damage has been too often observed and documented over generations for folks to realistically deny that tissue is damaged. (A good many hunters stuck with the 30-30 on deer over more modern, smaller and faster rounds, due to the destruction of too much tissue by the latter and the loss of edible meat.)

The problem is that the extent of the damage varies quite a bit. It matters where the bullet strikes. It matters how well hydrated a person or animal is. Temperature matters. It matters whether the animal or person being struck is at rest or violently active at the time they are hit. Caliber, velocity and bullet construction obviously matter. By "matter" I mean that these factors and others effect the extent of the damage.

So can there be remote damage to the nervous system as a result of the "pressure wave" created by the bullets passage as Courtney posits? Yep there could be. Col. Chamberlin, who Courtney cites, thought so. Chamberlin also thought it could not be relied on for incapacitation because of the many variables that I mentioned. What could be relied on was where you put the bullet and the choice of caliber and bullet type.

tipoc

 

[Loosedhorse]

Yep there could be. Col. Chamberlin, who Courtney cites, thought so. Chamberlin also thought it could not be relied on for incapacitation because of the many variables that I mentioned. What could be relied on was where you put the bullet and the choice of caliber and bullet type.

Can I have an "Amen!"?

[Just one more word about hematuria: this paper (discussed in this review) found that over 50% of patients did NOT have hematuria--gross or microscopic--after they had received...penetrating injury to the kidney itself!

So the absence of hematuria = no renal injury theory takes a big hit! (Of course, it could be another Czech student, perhaps?)]

 

[Odd Job]

JohnKSa says

As far as the latter half of the question, I'd say it's premature to look at BPW in that light at this time. I don't believe it's understood well enough to recommend that people to start altering their handgun self-defense tactics in an attempt to achieve it.

The only thing I think is advisable, in light of the possibilities offered by BPW, is to use expanding ammunition in handguns as long as it doesn't unduly limit penetration. Of course that's been pretty well accepted as the prudent course of action long before anyone began discussing/debating BPW.

I'm very interested in BPW because it explains some anomalies and contradictions that turn up when the theories of stopping power put forth by the "permanent wound channel is everything" crowd are beaten against reality. But I'm less interested in it (at least at this time) as a practical method for trying to significantly improve the chances of stopping an attacker with a handgun.

As an extension of Courtney's theory then, it needs a lot of work and experimentation to prove. I don't know if it is possible to do.
I'm at least glad to see that you don't seem to be advocating placement of shots in the abdomen.
If people stick with adequate penetration and good JHPs, that is all that can be asked. But with the (supposed/proposed) limitations that you set out earlier in your extended theory, I think it is a moot discussion.

 

[Odd Job]

This is the internet: why should I believe that you have worked in a hospital? Why should you believe I haven't? These appeals--believe what I say because of who I say I am? Pretty tiresome.

Actually it is about experience, research and relevant observations.
I've been there. I can tell by your posts that you have not.

Oh, don't worry: the fool's cap looks good on you--like you were born to wear it!

You just keep thinking that. I'm not going to bother with you any longer.

 

[Norrick]

I don't know the claimed specifics but I do believe it has some wounding effects. Disruption of valves who is to say. I remember hearing about a man who induced a stroke because he was pushing too hard while going #2. I know that the first time I tried doing a jump on my snowboard I belly flopped onto packed snow and the hit to the abdomen sent a sudden rush of pressure to my head. I had a bad headache for the rest of the day and I hadn't even hit my head.

I think in order to produce that effect a bullet would need to hit center mass (where all the fluids and blood are pooled, so to speak)so I don't think the added shock will have any substantial added effect on the already poor chances of said badguy/animal.

 

[MachIVshooter]

The vagus nerve originates in the brainstem, so anything that suppresses the brainstem will suppress the vagus nerve.

First, Vagus vs. Vegas; Have you ever posted from a "smart phone"? "Vagus" isn't in it's dictionary, and I don't always catch things that have been auto-corrected. Your snark, however, is not appreciated.

Secondly, the Vagus nerve is one of twelve cranial nerves, and it does not originate in the brain stem. Wiki actually has a pretty good (short) article on it:

http://en.wikipedia.org/wiki/Vagus_nerve

Third, the parasympathetic nervous system most certainly can control the release of adrenaline.

Of course: if the shock wave was significantly dampened in the body, then a) the renal stone could not be disrupted, because the energy would not reach it, AND b) the intervening tissue between the skin surface and the calculus woud be damaged as it absorbed the energy.

Do you understand the difference between a hydraulic shock wave and an acoustic shock wave? You cannot compare the sound waves used to crumble kidney stones to the shock waves generated by a ballistic impact. They aren't whacking the kidney in order to generate a stone-busting pressure wave; The accoustic waves that a Lithotriptor produces are intensly focused and have greatest effect on more dense and rigid objects, while a BPW would affect soft tissue much more and have little or no effect on bone, etc.

I think anyone who has ever hunted enough or even watched enough hunting shows has seen animals drop instantly from a shot to the body even though the bullet obviously didn't come anywhere near the components of the central nervous system. That is clearly evidence that the CNS was insulted/damaged via some means even though neither the permanent nor temporary wound channel impinged on the CNS. Does it happen all the time--nope, but it DOES happen.

Seen just as many run a good distance with their heart split in half-so would that clearly be evidence that a functioning circulatory system is not necessary for motor function? Because using the smae logic, that it the conclusion we arrive at.

I've also shot a number of animals in the head and watched them run-this definitely flies in the face of any BPW theory for instant incapacitation, as the only release for the pressure developed there is the bullet hole itself. Best example has been feral cats; Two of them were very much alive and moving quickly and deliberately after taking a .22 LR bullet through the cranium at literally point blank range (less than 10 feet).

It also seems that you're asserting under the assumption that there is no significant nervous system outside the scope of spinal cord and brain. In reality, there are many LARGE nerve bundles throughout the body that, when struck by the bullet or secondary missles, or when acted on by a significant temporary cavity resulting from GSW, certainly can cause the animal to act as though he's been struck by Thor's hammer. I'll again reference the 12 cranial nerves. So unless you dissected the animal and verified that absolutley no vital organ or nerve bundle was affected by the bullet, the permanent cavity or the temporary cavity, your theory is mere speculation at best.

 

[Mike1234567]

Differing tissue types react differently to hydrostatic shock. For instance, brain cells are completely different than long-stranded (stretchy/tough) muscle cells. A severe shock to the brain will cause far more ripping, tearing, and liquification than the same shock to muscle tissue which is more prone to temporarily stretching and deformation. Likewise, liver, kidney and other tissue matter will be less able to survive hydrostatic shock than muscle. So, IMHO, the effectiveness of hydrostaic shock is heaviliy dependent on shot placement. But... this has been covered many times.

 

[brickeyee]

The question was why a torso hit would cause an effect in the brain while a neck hit didn't show a stronger effect. If the neck doesn't have the kind of tissues that couple projectile energy into blood vessels very well then that lack of coupling efficiency could mean that a hit in the neck might result in a weaker effect to the brain even though it's closer to the brain than the torso.

Unless you happen to affect the carotid arteries.

Things like this are so specific to each shooting that general conclusions are almost impossible to derive.

There are thousands of variables in play, and even shooting the same gun at the same animal in the same spot may not produce a repeatable result.

As a real science, terminal ballistics is not going to get there for a very long time.

We simply cannot even account for all the tiny changes and the sometimes major effects they create.

 

[Shawn Dodson]

I think anyone who has ever hunted enough or even watched enough hunting shows has seen animals drop instantly from a shot to the body even though the bullet obviously didn't come anywhere near the components of the central nervous system. That is clearly evidence that the CNS was insulted/damaged via some means even though neither the permanent nor temporary wound channel impinged on the CNS. Does it happen all the time--nope, but it DOES happen.

The bullet does not have "to come close" to CNS structures to physically disrupt the CNS. The shape of an animal's body can focus the effects of temporary cavitation on spinal bones (in the manner of a parabolic reflector), in which they physically collide violently against the spinal cord to produce a concussive effect that causes instant flaccid paralysis.

 

[JohnKSa]

Unless you happen to affect the carotid arteries.

I'm not saying it couldn't happen, I was speaking specifically to the comment about why neck injuries didn't seem to create a higher incidence of BPW effects since the neck, being closer, would clearly generate a stronger BPW to the brain. The comment was made that the fact that they didn't seem to was evidence against BPW. I'm not saying that there's no way to couple the energy into the veins in the neck from a neck hit, I'm only suggesting a possible explanation as to why BPW effects might seem less likely as a result of a bullet strike to the neck.

There are thousands of variables in play, and even shooting the same gun at the same animal in the same spot may not produce a repeatable result.

Yes.

The shape of an animal's body can focus the effects of temporary cavitation on spinal bones (in the manner of a parabolic reflector), in which they physically collide violently against the spinal cord to produce a concussive effect that causes instant flaccid paralysis.

Seems reasonable. So those effects are so powerful that they can physically drive a piece of bone against the spinal cord hard enough to cause instant paralysis.

Maybe those effects are also so powerful that if they are focused against blood vessels they might cause a pressure wave to travel through them.

 

[Odd Job]

Shawn Dodson says

The bullet does not have "to come close" to CNS structures to physically disrupt the CNS. The shape of an animal's body can focus the effects of temporary cavitation on spinal bones (in the manner of a parabolic reflector), in which they physically collide violently against the spinal cord to produce a concussive effect that causes instant flaccid paralysis.

Are you talking about rifle or handgun injuries?

 

[Loosedhorse]

Secondly, the Vagus nerve is one of twelve cranial nerves, and it does not originate in the brain stem.

My goodness you DO go out of your way to make these mistakes! And are so adamant about them.

The cell bodies for the axons of the vagus nerve (its origin) are contained in the nucleus ambiguus, doral nucleus of the vagus, and the nucleus solitarius--all in the brainstem. The nerve itself begins where those axons emerge for the dorsolateral surface of the medulla (at the level of the inferior olive)...and the medulla is part of the braistem. Whether wiki says so or not.

Third, the parasympathetic nervous system most certainly can control the release of adrenaline

Can? As in, by magic, on certain days?

No, it does NOT. Looks at your own favorite reference, wiki, for pete's sake: the adrenal glands have SYMPATHETIC innervation. Nothing about parasympathetic, and certainly nothing about vagus--your earlier claim (which you have slithered away from?).

Here's your dunce cap. Go stand in the corner.

Can we just say as a blanket statement that everything you say about human anatomy is wrong? I mean, how many mistakes have you made so far? And you're NOT making these mistakes on purpose, as a gag??? Wow: the arrogance of ignorance.

The shape of an animal's body can focus the effects of temporary cavitation on spinal bones (in the manner of a parabolic reflector)

And where, please, is the evidence of the parabolic-reflector theory of spinal injury? Hey, I'm not saying you're wrong, but aren't you one of the guys dismissing the BSW as unproven? Yet you feel comfortable invoking the deer body as parabolic mirror theory? One unproven theory as disproving a different unproven theory?

And yet there is no similar parabolic effect for human bodies?

Actually it is about experience, research and relevant observations.
I've been there. I can tell by your posts that you have not.

Okay, now you're not just claiming you worked in a hospital (janitor? Orderly?), but to have done research--perhaps on this very subject? Some published citations would be nice. Otherwise, you're just blowin' smoke.

Sad, really. You're so puffed up with your own self-important "experience" that you feel comfortable attacking me as inexperienced with no support whatever, except your opinion. You can't recognize another's experience? That's your own fault. Well, we've all met your type.

By the way, Mr. Experience, why no comment on the vagus nerve? Why leave that mess for me to clean up? Or isn't that within your vast experience?

 

[Mike1234567]

I wonder if the success of hydrostatic shock is, more simply, a sudden devastating burst in blood pressure which might cause rupturing of blood vessels within the brain.

 

[MachIVshooter]

My goodness you DO go out of your way to make these mistakes! And are so adamant about them.

The cell bodies for the axons of the vagus nerve (its origin) are contained in the nucleus ambiguus, doral nucleus of the vagus, and the nucleus solitarius--all in the brainstem. The nerve itself begins where those axons emerge for the dorsolateral surface of the medulla (at the level of the inferior olive)...and the medulla is part of the braistem. Whether wiki says so or not.

Been going off of memory from casual reading of A&P books years ago. I just cracked it again to check, and my error comes from remembering that the Vagus emerges at the top of the medulla, between it and the pons. I did not recall the pons and midbrain being considered part of the brainstem (and it seems there is some ambiguity about what, besides the medulla, is technically "brainstem")

My recollection of it's control of adrenal respose was backwards; Forgot the vagus serves to counter the increased heartrate caused by adrenaline.

All that said and errors included, my original point remains; General anesthesia does not shut down the entire autonomic nervous system, as was claimed. Anesthesia itself is a peculiar thing, and thats why there are anesthesiologists who do nothing but monitor vitals and administer the entire time. And respirators are not always necessary....

Here's your dunce cap. Go stand in the corner.

Can we just say as a blanket statement that everything you say about human anatomy is wrong? I mean, how many mistakes have you made so far? And you're NOT making these mistakes on purpose, as a gag??? Wow: the arrogance of ignorance.

Can we just make a blanket statement that you're a jerk? The rest of us are trying to have a civil conversation here, but you've directly insulted some of us. Not very high road.

And you still haven't answered whether you understand the difference between an acoustic shock wave and a ballistic shock wave or pressure wave. You do at least get that there are different kinds of waves, yes?

 

[Mike1234567]

Looky What I Found

 

[MachIVshooter]

Looky What I Found

Once again, no one is arguing the presence of a pressure wave, but what it's effects are. Certainly 500 or 1000 PSI would be harmful; Thing is, as the pressure wave travels in a 3-dimensional parabolic shape, the pressure attenuates at an exponential rate. Even excluding the shock-absorbing capabilities of soft tissue and presuming pure liquid, that dissipation is still geometric. Double the volume of the wave, halve the pressure. Double it again from the volume (not diameter or circumference) of the last increase, halve the pressure again (1/2, 1/4, 1/8, etc.) and so on.

Someone with better math skills can probably articulate this more effectively than I can, but this is concept rather than exact, so we'll use simple linear math for it. Now remember that spherical volume is calculated at a factor of 4/3*pie*radius cubed, (roughly 4.19*radius cubed) so a semisphere (hemishpere) is half of that (4.19*Radius cubed/2).

For the purpose of these illustrations with my rudimentary geometry skills 15 years since I studied, we'll use the calculation of a true hemisphere rather than a half ellipsoid with cylindrical base or other shapes that make volume calculations more difficult.

So, if calculating using a .45 cal RN {(4.19*.225cubed)/2}, we have a pressure wave point of origin (POO) resulting from a displacement of .05CI. Suppose the pressure at POO is 1,000 PSI. Increase the area of our pressure wave by a factor of 2 (a .9" semisphere diameter) and now you have a volume of .19CI. Assuming a linear dissipation, we have to take the 1000 PSI we began with and divide it by ~4 (.19/.05). So only .225" from the POO, our pressure is reduced to 250 PSI. By the time you get an inch away from the POO (1.225" radius semisphere with a volume of 3.85CI), pressure is down to ~13 PSI.

As I said, my math is not as good as some of our members who could accurately calculate with a correct elliptiod (and superscript that I can't figure out how to get). The point remains.

Some variables to consider that require better math skills and a lot more specific details than I (we?) have at hand:

Causing pressure to be greater than the simple equation:

-The math I did is very simple and assumes a static pressure; The velocity and magnuitude of the pressure wave will affect the pressure as it travels outward, resulting in a pressure differential on either side of the wave with greater pressure on the outside.

-The pressure will not be equal across the arc of the wave; it will be greatest at the front.

Causing the loss of pressure to be more dramatic than simple math indicates:

-As with the pressure, the magnitude and velocity of the wave will decrease as it travels; Drop a boulder of, say, 50 pounds from a height of 5 feet into a 50,000 gallon pond, you get a big splash and fast moving wave right next to it, but very small and slow wave at the shoreline.

-Pressure will continue to be generated as the bullet travels deeper, but at a decreasing magnitude as velocity is shed; Countering this, some of that pressure wave will dissipate behind the hemisphere as the bullet penetrates deeper, causing the dissipation to become more spherical, and thus increasing the loss.

-Unlike shooting into a bucket with a homogenous liquid medium, the human body is a conglomeration of different tissues that are separated by membranes and other fascia, as well as just space. They're also all contained within a flexible, expandable unit and able to compress/expand and absorb impact themselves; Every part of the human body is designed to absorb and dissipate impact and pressure to prevent injury (The exception being the brain, which is contained rigidly and does not tolerate much pressure). Now, Imagine the hydraulic shock of shooting a water ballon filled with ballistic gelatin. Then imagine what the effect will be on a gelatin-filled water balloon placed next to the one that is impacted, with a couple sheets of clingwrap between them and a 1/8" layer of shaving cream between those sheets. Now imagine the pressure that is generated in a thin tube made of, say, latex, filled with water when it is wrapped around the balloon that isn't struck. Can you see where I'm going with this?