Explain this?

[Art Eatman]

dZ, to say it a bit differently than freestate, I think it's more likely the strength of the container walls, rather than the size of the container or the temporary cavity...

I agree with your first sentence about the temporary cavity, but "When the size of the container is smaller then the area of displacement, the container ruptures." is problematic. A five-gallon bucket of water will certainly rupture, and photos of the cavities in e.g., gelatin, don't show cavities anywhere near that large...

I guess you could cap both ends of a short piece of 2-1/2" galvanized pipe, full of water, and try a rifle on it...I doubt it would notably "rupture" in an explosive manner.

FWIW, Art

[dZ]

gee, y'all sound like my wife


i doubt the energy in a .308 has the power to explosively rupture the walls of a steel cylinder. (although water is fairly non compressible)

What i would try would be to put jelly in various sized capped plastic containers and determine what volume of container has the capacity to contain the shock. A free standing non skinned block of Jelly might deform but rebound. IMHO the skin acts as a stretch limiter. Once the energy in exceeds the skins containment capacity... it blows up real good.

I am basing this hypothesis of hydrostatic rupture on some web conversations with a LTC i know, and some field experiments.

dZ

[Art Eatman]

Keith, re-reading your comment on hydrostatic shock called to mind an article on one of Roy Weatherby's early "test hunts" in Africa.

He used either a .270 Wby or a .300--don't now recall--and shot an eland in the hindquarter, from the side. (Lousy shooter?) Anyway, it was a one-shot kill. The eland dropped like a stone, per the article. The obvious question is, what else BUT hydrostatic shock could have killed the animal?

Anyway, R.W. always claimed that the kill-efficiency of his (then) ultra-high velocity loads was due to hydrostatic shock...

FWIW, Art

[Paul B.]

Art. Regarding your comment about the cavity remaining in gelatin. I agree that the cavity showing is not that large, but what about the temporary cavity? Might not that be substantially larger? Say large enough to cause the disruption necessary to create the damage?
Paul B.

[This message has been edited by Paul B. (edited July 28, 2000).]

[Keith Rogan]

Art,

Something sure killed that Eland! This is a very complex issue that involves a whole range of disciplines from fluid mechanics to physiology - its not something we'll solve here in this thread.
But SOMETHING kills animals hit with high speed bullets. Something beyond mere tissue damage and bleeding.
I have my theories but admittedly, they are based on very imperfect knowledge. Whatever the cause, it has to involve the Central Nervous System - nothing else can switch an animal "off" like that.



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Keith
The Bears and Bear Maulings Page: members.xoom.com/keithrogan

[Art Eatman]

Paul B: I've read many articles in the gunzines through the years that show the high-speed photos of various bullets going through gelatin. Yup, the temporary cavity is commonly rour or five times the diameter of the remaining cavity. Translating this into mammalian tissue implies that there is tremendous tearing and bruising of organs and muscle around a bullet's path. As I've disassembled various deer, I've opened up the pathway just to look; it's a mess! (Doing that is a good way to teach one's kid that a gun is not a toy; and that meat on the table takes some work, first.)

A lung shot shows the results of a temporary cavity more than other hits, I think. At least the extent of damage at a distance from the bullet's path leads me to say this; a shot through a ham messes up meat, but not to such a distance from the bullet's path.

Keith: Raggiejack brought up a rational concept, but, yeah, we won't create a definitive answer in this forum. In the meantime, it's food for thought and I think it obviously makes sense. "Hydrostatic Shock" may be just another name for this phenomenon.

I guess we could agree that a hit from a bullet travelling over 3,000 to 3,500 feet per second can kill fairly instantaneously even though the hit is not in a vital area. Which still doesn't explain how some animals can take such a hit in a vital zone and just look insulted.

I've gotten where I hate two words: "Always" and "Never"...

Regards, Art

To all- yes this has been a great discussion. This is what I feel makes TFL a great place.

Mr. Rogan,

I may be wrong but I don't think so. I have searched the literature on medline, looked at several trauma references, and discussed this with a few individuals more knowledgeable in this field than I. Serious autopsies are done on people when they are shot, including brain sectioning, and they just don't show an intracranial bleed/stroke.

Even if it did, people/animals can take quite a large bleed in the head and still function for a short period. I have seen it frequently.

The arterial system is very resistant to rapid pressure spikes because there is a huge surface area of little arteries(arterioles) at the end which help dampen the pressure.

Now there are a few other options other than stroke. The large arteries could be torn and cause a dissection of the artery occluding the carotids, or an air embolism could be introduced- neither of these would be instantaneous however, and would at least require a minute or so to take full effect.

Keep in mind you see the animal drop instantly, but how long before you check to see if it is alive? Just because it dropped does not mean it died instantly.


You bring up a very good point Mr. Rogan. The entire body is crammed with fluid filled goodies making it a semi solid. The arteries are expandable and part of this complex mass. The pressure wave should not run up the arteries like a solid metal pipe. instead it will dissipate through all the tissues up into the head, not just up the arteries.

I also agree that there is a "something" besides loss of BP and CNS hit that incapacitates. I believe the answer lies in the adrenaline dump. Just as it can bring the dead back to "life" for a short period, it can certainly prolong it. It squeezes the blood out of the periphery and increases the heart rate thereby providing blood to the central organs and brain.

The hydrostatic shock theory just has too many flaws for me to buy it. IMHO- the best answer lies in the psycological state of the animal/human and therefore the potential for an adrenaline (and other hormone)"dump". Most have repect for the motivated crack/meth/PCP psyco and how hard it is to put them down. I would place adrenaline in the same category (the reason these drugs are so powerfull is probably due to the adrenaline dump).

Anyway- all of this is just my single humble opinion. Sorry for the long post and my absence, I haven't logged on for a couple of days.

Olazul

[Keith Rogan]

Olazul,

I'm certainly not married to my theory and am willing to dump it at a moments notice when a better one comes along.
Its just that I can't imagine anything other than the CNS "switch" being tripped as killing an animal that rapidly.
A French doctor once did an experiment with a friend who was facing the guillotine. The doctor would pick up the head and his friend would blink in answer to questions. I forget how long the head remained alive but it was a surprisingly long time - 15 seconds, 30 seconds, something like that. Quite a gruesome description - the guy was blinking away and trying to mouth words- possibly: "Oh Merde!".

I have shot animals at close range (close enough to observe) and "switched them off" instantly. They may not have been dead instantly - maybe they were unconscious for a while. It doesn't matter really. It was too quick for any type of adrenaline or hormone dump to take affect. Wouldn't that take at least several seconds to get in the blood stream and begin ciculating?




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Keith
The Bears and Bear Maulings Page: members.xoom.com/keithrogan

[MAD DOG]

The discussion about when "brain death" occurs is, in all probability, nuncupatory, as the body can still be ambulatory and damaging to the locale despite the apparent lack of an effective brain.
Witness Al Gore...
I am more interested in actual physical death, to wit:
How do we tell when Democrats are actually dead, as opposed to just brain dead?

Forgive me if I have swerved to wildly off of the topic direction...

Mr. Rogan,

I think my last post was confusing- not enough sleep I suppose. I merged two thoughts together.

What I meant to say was that to kill instantaneosly would require a CNS hit or instant loss of blood pressure(this latter being very difficult to achieve- but possible).

The other "something" I envision as psycological- giving up(falling down) and dying vs fighting/running and dying. The cause for the fight/run then die is the adrenalin surge. In those animals/humans who fall(appear to die) instantaneously the adrenalin surge is absent(I think anyway)- perhaps they faint due to the psycological trauma and the physical trauma kills them in a few minutes.

I would think the adrenaline surge would take a couple of seconds to get from the glands, into the blood, and effect the organs. The last time I almost got into an accident my heart started pounding fast very quickly though.

I certainly do not have proof for any of this. I do see a fair amount of trauma though and if the hydrostatic shock theory was really happening I would think it would be seen in other nonpenetrating trauma's as well that cause tremendous pressure waves in the body. The stroke theory would have certainly been reported in the literature.

Perhaps we should seperate the terms incapacitation and death.

I have heard of the guillotine story- that is pretty creepy but makes sense to me.

The bottom line is that no one knows for sure why someone falls down(gets incapacitated) when they get shot(as long as no instant death from CNS or BP). My experience and background make me doubt the hydrostatic shock theory in favor of a psycological(end result adrenaline or lack thereof) explanation.

But .02 probably more than my opinion is worth .

Olazul

[Keith Rogan]

Hey, only my 9 year old sons friends call me "Mr. Rogan", everyone else calls me Keith.

I followed your note, thats why I posted that story about the guillotine. Having your head chopped off is an "instant loss of blood pressure", yet the individuals remain alive, even coherent for some seconds afterwards.
The blood contains oxygen and even if you shut down the pump instantly (or even remove the head from the body), there is apparently still enough oxygen in the residual blood in the cells to "fuel" life for some 15-30 seconds.




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Keith
The Bears and Bear Maulings Page: members.xoom.com/keithrogan

[KODB]

Interesting thread.
I've tried to think about this in terms of physiology and what actually happens to trauma patients in my experience (both human and those oh-so-tasty bambi's).

I suspect that the answer is both more complicated and simple.

Lets do the simple first. I suspect (though can't prove) that the real answer to the question is hydraulic failure and rate of failure. I suspect that it IS acutally acute hemorrhage most times than not when the heart is shot: the kicker is that it is not the shot through the heart per se but the disruption of the great vessels. People who have blunt traumatic disruptions of their aorta and who arrive alive in the ER (i.e. contained dissections) and then rupture die in the course of about 2 seconds. They lose BP and instantaneously go unresponsive. Similarly, when you take a patient like this to the OR, open them and the thing ruptures before you can get a clamp on it, the patient exsanguinates into the thorax in the course of 2-3 heartbeats. This is true; I've unfortunately had occasion to see it happen a few more times than I would like. Similarly, when you get an injury to the pulmonary artery during open heart surgery the same phenomena occurs: the chest fills with blood and you're done. When I've done thoracotomies in the ER for penetrating chest wounds on people who were down at the scene and unresponsive but who arrived with some electrical activity the most impressive hemothoraxes I've seen involved great vessel disruptions: they all universally died.

OTOH, there are numerous patients I've taken care of with stab wounds or GSW to the heart itself who come into the ER/OR still cussing out everyone in sight and fighting for all they're worth. Most of these folks had through and through wounds to the heart WITHOUT associated great vessel damage. Althought they all had some degree of tamponade or hemothorax each was still able to move/fight/run/react.

I do not buy the "hydrostatic shock wave" theory for similar reasons to Oazul as I have not seen any brain bleeds on autopsy despite brain sections of a multitude of GSW victims.

So, I think that what happens in the instant kill is either the heart disintegrates and hence bleeds out quickly/instantaneously, OR the great vessels are injured/also injured and bleeds out quickly/instantaneously, or a clean through and through type wound results and the animal bolts until it exsanguinates over time, or more than likely, develops a tension pnuemothorax and then dies. Either of the last 2 items require at least a 30sec to several minute interval vice the instant collapse and death deal. Rounds that bleed more energy into the mediastinal area are more likely to cause disruption of the great vessels or just flat-out explode the heart. Rounds that pass through (i.e. "overpenetrate" in this scenario) will only cause said disruption with a direct hit; the probability based on the area of the mediastinum/heart is that they will not clip a great vessel the majority of the time and since they're simply passing through will give you a prolonged vice instantaneous death.

I do think that some folks/animals hit in thorax may also be killed by massive air embolism resulting from disruption of the alveolar/capillary junction with escape of large volume of air into the arterial circulation; this takes a few seconds but less than that to develop a tension pneumo or exsanguinate into the chest from a clean heart wound. It also takes a massive pulmonary injury and a large volume air.
The mechanism of this is simply a bubble obstructing flow in one of the BIG cerebral arteries or even the internal carotid and causing loss of consciousness followed by death. This mechanism is readily understandable if you've ever seen someone with a really BFE (big f******* embolism) drop over as soon as they reach the surface following a dive. It's quite impressive.

Well, that is the my .06 cents. I'll be happy to clarify anything that seems too jargon laden or confusing, but I think that this is the most probable explaination for whats being debated.

Cheers all,

Bob

[This message has been edited by KODB (edited July 30, 2000).]

[This message has been edited by KODB (edited July 30, 2000).]

[Al Thompson]

We've hit the limit - thread size wise anyway.

Giz