Minimum wound channel, bullet selection and Shooter's Notes

[grayfox]

From a link on a previous thread I got into JAS's shooters notes on wound channel, bullet selection and penetration depth etc etc. The part talking about the effective "wound tube" going through the thoracic area needing to be a certain diameter/volume to cut sufficient arteries/veins for rapid blood pressure drop makes a lot of sense. I'm enjoying the theories, data and results he's got there. It is truly an excellent website!! shootersnotes.com

But one question, kinda technical... the trauma "tube" diameter seems to be, if I read it right, based on the deformed bullet's cross-sectional area. For a bullet going within mfr expansion envelope, seems to me that might be a bit too conservative? What I mean is, should some benefit be given to the wound-channel disruption/volume (like in gel material) ie, maybe the internal wound channel volume which will be somewhat bell-shaped (or, in 3-D kind of a sideways minaret shape)? This is just a "just wondering out loud" question, but the trauma caused in that thoracic volume I would figure would also cause some arterial breakage/tearing...

Anyway for the theoretical guys out there, I pose this question.

[Kswhitetails]

There are two parts of a wound, the "injury" and the "trauma". My best guess is that the "trauma" is what's left after the dust settles, IE the permanent changes made to the affected area. The hole left by the bullet, measured after things have collapsed back to their normal resting position, would be - i think - what you're reading, and I agree with your interpretation. I also agree that there is another part of the wound not left behind, the "balooning" and temporary disruption of the fluid based shoc kwave that travels through the path of bullet impact. I'd be inclined to believe this is more "disruptive" to functions and abilities than the "trauma" ever would be. Evidenced by FMJ wound channels and gel testing. Things settle right back together, and there is much less of an imparted shock wave.

The energy imparted upon impact is 90% of the measurable lethality of bullet impact in my view. This is why we all know not to shoot to kill with sleek FMJs. They are, by design, intended to pass through the surrounding fluid with as little energy loss or disturbance as possible. No wonder they aren't all that great for anything other than injury and temporary casualty status. Almost all of the bleeding in a gunshot is caused by the lacerations caused in the tissue when that shock wave is traveling through the body cavity. Therefore, the wound, including the "injury" should really be measured and not just the size of the hole left behind. Otherwise, given the same projectile impact and path, shooting someone with a field point carbon arrow would be just as lethal as a 357 magnum...

[Double Naught Spy]

The energy imparted upon impact is 90% of the measurable lethality of bullet impact in my view.

That sounds really scientific. What exactly is measurable lethality? How is it computed? Is it supposed to be real or one of those phrases that is nothing more than an attempt to categorize a series of numbers (like knock-down power, Taylor's KO index, etc.)?

This is why we all know not to shoot to kill with sleek FMJs. They are, by design, intended to pass through the surrounding fluid with as little energy loss or disturbance as possible.

I am not sure that you will ever find any FMJ designs that actually include such a parameter as being intended to pass through surrounding fluid with as little energy loss or disturbance as possible." I don't know that was ever a design intent of FMJ, but if you have a source, that would prove quite interesting.

My point here is that design, design intent, real life application, and real life results often are unrelated. That a product performs in a given manner often has nothing to do with design intent. That FMJs often pass through as they do would appear to be much more of a developmental construct following the use of technologically limited lead ball ammo to a round that fired more effective from a rifled barrel with less fouling.

[grayfox]

JA's theory of quick kill is rapid blood pressure loss within 10 seconds so that you get brain and muscle shutdowns -- which is not bad as a quantification of the wounding objective. My question is not how well, or not, FMJ's work (I'm told they tumble inside the body as the tip slows more than the base, but I could be wrong), but rather in trying to quantify the wounding/blood pressure disruption, would it be more accurate to factor in the shock-wave volume somehow, as well? I would hypothesize that not all blood vessels in that volume would be cut/torn/ripped, but maybe, what, 50% of the volume could count towards the BP collapse...

Anyway this may be more like arguing about whether it's a stainless or carbon steel needle upon which the angels are dancing... sometimes these questions pop into my head when reading this type of work. Which did I say, is a really good writeup by the way.
I like digging into technical details from time to time, what can I say?

[JASmith]

Nicely said!

We can debate the value of hydrostatic/hydrodynamic shock — it is real and a significant wound generating mechanism. It is one of the reasons we joke about squirrels jumping 6 ft when hit with a high velocity varmint bullet.

My hiccup is that lead core bullets tend to disentegrate when going fast enough to generate serious hydro shock. This tends to leave surface wounds in medium and large game.

Bonded, partition, and lead free hunting bullets tend to hang together at higher velocities, raising the possibily of hydro shock AND decent wound channels.

But, we don’t need the hydro shock to make the Grendel and other modest velocity cartridges superb game harvesters.

[Kswhitetails]

DNS- Hey, who asked for science? I'm thinking of running for office and thought this would be good practice. Sounding scientific is what we theoretical pontificators do. It's a calling. You caught me, I got carried away. But- to answer:

Call my source good ol'fashioned Oklahoma Engineering, forged by tractor repairs in cotton rows with grandpa when things went to "fix it soon, or die from a thousand cuts" mode. Observe, theorize, try and fail; repeat.

There are all kinds of studies done on the lethality of gunshot wounds encountered by medical, police, and first responder personnel. All done to help make decisions on how to better aid the victims of future shootings. I can't and don't need to cite them, anyone can search the data if they wish. Long story short, hollow points, expanding projectiles, and frangibles are much more lethal than FMJs. And it's not because one leaves a bigger hole behind, or not only because of that; but because the damage caused by the energy wave blasting through the victim destroys so many things beyond repair. ER nurses will tell you that blood vessels are more likely to be catastrophically damaged beyond repair from an impact injury with enough force than from being cut. There is a term even for the laceration formed by the impact of a hard edge or corner against resilient tissue, which is a similar injury on a smaller scale, but I can't remember that term either... Exploding vessels are almost always the cause of irreparable bleed-outs and delayed internal bleeding deaths. Especially when involving the larger vessels. Aneurysm, anyone? The energy dumped into the cavity, and the resulting cavitation is much more devastating to the tissue than the nice clean hole left by a sharp edged object.

As far as the passing through fluid with as little energy loss as possible, I ask: what is the idea behind the science of creating/calculating higher BCs? Isn't it exactly to design a bullet that moves through the air with as little resistance as possible? Secondarily, why are FMJs called for in the Geneva conventions? The Geneva agreements call for bullet designs that dump as little energy as possible into the target, increasing the chance or likely hood of low trauma pass-through so that the resulting wounds are less lethal, or at least this is my understanding in general terms...The air we breathe and the atmosphere we exist in are considered fluids by some; I recall learning this while discussing Bernoulli's discovery of airfoil lift in 6th grade. It's how the aerodynamics of just about everything is measured: how easily does it move through the air, or using another term, our fluid atmosphere? The dynamic forces calculated on an object moving through the atmosphere, and the same object when under water, only differ in the density numbers used in the equations. (This was my understanding of the simplified explanations I received long ago; you know, there was something I forgot once, I just can't remember what it is...)

Obviously, any object traveling at extreme speed that encounters another object moving slowly is going to transfer energy on impact. By their design, some can do it better. No one I know would suggest high BC FMJs (we're talking true FMJ, not OTM, or 7N6 designs) to ethically kill anything. We all know they will do the job. Any animal with a hole in the heart is dead... I'll leave the data gathering and mathematical proofs in game animals to the engineering students and mathematicians, of which I am neither. I am smart enough though, to observe the world around me and figure out that a hollow point isn't made that way because it makes a bigger hole - that's the secondary benefit. Hollow points and soft points or partition rifle bullets or expanding solids are made to dump energy into the encountered "liquid vessel target" as quickly and efficiently as possible and cause millions of cell walls and capillaries to rupture, dumping their contents into that newly created hole. The hole being bigger - rather than the benefit - is simply a secondary result (though we all know a bigger hole lets more blood out... jeez GF what have you started). I think this is what GF was discussing in the OP?

I thought we were theorizing here, what's this call for data?? I missed something again!

(Hey DNS- Police: Hollow points: (he dead = 9x more effective x resist (thug with gun -bad guy license)-(FMJ x 20/running away))

I hold little hope of being elected.

[grayfox]

One reason I'm curious is there are now some bullets that don't function by the typical entry-expansion method, example, the Lehigh controlled chaos... they are lead-free and fracture into rather large pieces after entry and those pieces travel in slightly differing trajectories -- thus creating an urge for enlarging the theory to handle cases like this.

KS, you might not get elected but for sure you could be hired as a Prof. for the Interweb College in Hyper-theoretical bullet quasi-qualitative applied trajectorial path-ology..... HAHAHAHAHAHAHA!!!!!!!

[JASmith]

Hydrodynamic shock is viewed as a near-magic event by too many folks.

One thing to remember is that properly designed hunting bullets transform themselves into something that looks like a flattened ball within a few inches of entry. Like the arrowhead, the design goal is to create a cut that can cut enough blood vessels to cause rapid fainting. Interestingly, the bullets with good reputations as game harvesters seem to correlate with arrowhead sizes from 5,000 BC to present. (It is harder to get good modern anecdotal data because state and national regulations in some parts of the world push to a one-size fits all mode of production.)

Back to hydro shock -- try an experiment with a .223 and plastic water containers: 16 oz, 1-gallon, and 5-gallons.

The 16oz bottle 'explodes' and the 1 gallon jug breaks apart with some authority while the 5 gallon jug usually just grunts.

The responses are analogous to hits on different sized game animals or extremities versus main body of medium game. If there is a surface near enough to the impact that the skin can tear or rupture, we get more spectacular results. Striking the shoulder or rump on a 1000 lb animal with one of these hydro shock bullets will indeed cause spectacular craters but not likely enough damage to bring the animal down.

I don't dispute damage to capillaries -- that damage can become fatal. If capillary damage is the only wound present, however, it will not likely cause collapse soon enough that a wounded animal can be reliably recovered.

[JASmith]

One reason I'm curious is there are now some bullets that don't function by the typical entry-expansion method, example, the Lehigh controlled chaos... they are lead-free and fracture into rather large pieces after entry and those pieces travel in slightly differing trajectories -- thus creating an urge for enlarging the theory to handle cases like this....

For the time being, a conservative approach is to treat them as lead-free expanding bullets. The Lehigh Controlled Chaos are likely are doing at least as well as their expanding counterparts. What makes me wonder, is that these fragments are each smaller than parent bullet, but are on diverging trajectories. The divergence with at least the same summed cross-section adds to the chances of intersecting critical blood vessels.

[Double Naught Spy]

DNS- Hey, who asked for science? I'm thinking of running for office and thought this would be good practice. Sounding scientific is what we theoretical pontificators do. It's a calling. You caught me, I got carried away. But- to answer:

Call my source good ol'fashioned Oklahoma Engineering, forged by tractor repairs in cotton rows with grandpa when things went to "fix it soon, or die from a thousand cuts" mode. Observe, theorize, try and fail; repeat.

Okay, so you made up the concept of measurable lethality of bullet impact and assigned a percentage to make it sound good. Got it.

As far as the passing through fluid with as little energy loss as possible, I ask: what is the idea behind the science of creating/calculating higher BCs? Isn't it exactly to design a bullet that moves through the air with as little resistance as possible?

Okay, so you are mixing aerodynamics with hydrodamics. Gasses are considered fluids in physics, but bullets often behave differently in gaseous fluids and liquid fluids, in particular when there is a transition gas to liquid, and it is the liquid fluid aspect that was relevant to lethality topic.

Secondarily, why are FMJs called for in the Geneva conventions? The Geneva agreements call for bullet designs that dump as little energy as possible into the target, increasing the chance or likely hood of low trauma pass-through so that the resulting wounds are less lethal, or at least this is my understanding in general terms...

Now you have provided considerable misinformation. There is absolutely NOTHING in the Geneva Convention about bullet designs - ball, fmj, expanding, etc.. There is discussion in the 1899 Hague Convention, but there is NOTHING about energy dumping. The Hague Convention did not call for the use of FMJs, either, but the use of non-expanding bullets. These two concepts are not the same thing.

Why you ask? Because of the British use of dumdum bullets in the northwest Indian Empire (now Afghanistan/Pakistan region) that were considered an improper practice spanning from the accords of the Saint Petersburg Declaration of 1868 that stipulated ammunition under 400 grams that was explosive not be used. Such ordnance was considered improper between civilized nations (as if war was civilized) as the wounds inflicted should not superfluous or cause unnecessary suffering. This was carried over by the Hague Convention in the attempt to limit such superfluous wounding and unnecessary suffering.

So somewhere in there, you have transmogrified superfluous wounding and unnecessary suffering to mean the same thing as dumping energy.

You may read the Hague Convention on the matter here which also provides a link to the Saint Petersburg Declaration. You may find it interesting.

http://avalon.law.yale.edu/19th_century/dec99-03.asp

You can get the quick Wiki version of the Geneva Convention(s) which came much later, first in 1929, 30 years after the Hague Convention.

https://en.wikipedia.org/wiki/Geneva_Conventions

I thought we were theorizing here, what's this call for data?? I missed something again!

I didn't call for any data. You provided a specific percentage and applied it to what appeared to be some sort of index (or at least referenced data that would have been comprised to create the imaginatively created "measurable lethality of bullet impact"). I just wanted to know about the science behind this concept you brought up.

[grayfox]

For the time being, a conservative approach is to treat them as lead-free expanding bullets. The Lehigh Controlled Chaos are likely are doing at least as well as their expanding counterparts. What makes me wonder, is that these fragments are each smaller than parent bullet, but are on diverging trajectories. The divergence with at least the same summed cross-section adds to the chances of intersecting critical blood vessels.

You're probably right. For purposes of what you investigated using the bullet-expanded caliber-tube volume is certainly a workable and measurable concept. I would hazard a corollary that, if extra blood vessel damage is caused "near to" that tube thus effectively enlarging its "volume" it is some percentage factor that is relatively constant, so your model would still apply as usable "theory" even though the "reality" might be some percent larger. And I would agree, capillaries wouldn't count, you need tearing of larger arteries/veins along with any that are actually cut.

Also we should clarify about hydrostatic shock. What I read a long time ago is that only projectiles traveling greater than 2200 ft/s at impact can cause enough shock to be its own effect. Plus, I don't think the wound cavity (the "sideways minaret" you see in gel tests) equates to that shock. A projectile of sufficient mass (the bullet) impacting a large fluid container (the animal's body) at a high enough velocity will cause a shock wave to propagate some distance through that fluid at the speed of sound in that medium -- the fluid as far as the wave is concerned, is more like a solid, a transmission medium for that traveling wave. If that wave is strong enough it can disrupt the CNS and can stun, cause unconsciousness, or death, but it is not the same thing as the damage created some microseconds later as the bullet plows a wound cavity through that fluid/body.

[JASmith]

Speaking of fluid effects that are at a tangent to the hydrodynamic shock phenomenon:

The Fluted Lehigh Defense bullet creates a fair-sized wound channel without expanding. The flutes are designed to send a jet of fluid sideways at a speed that is proportional to the bullet's velocity. The fluid is going fast enough to cut flesh at a significant distance from the bullet. The effect allows both deep penetration and wide wound channels.

Quantifying this will take a fair number of gel tests.

Also, the bullet doesn't expand, which may cause interesting conversations with game wardens until the designs are accepted as being as or more humane than traditional or lead-free hunting bullets.

[grayfox]

I have some 110 Lehigh's for my grendels, but am just as interested in 123's, 100's or other ones that work well. I don't have a huge stake in Lehighs, just wanted to disclose that. This set of articles you wrote piqued my curiosity mostly, academically speaking. Sometimes by digging into a topic I can learn a few things that might become useful later on.

Would be interesting if you all decided to visit some of these ideas with some more testing... funds and stuff availability allowing, of course!

ps, the speed of sound in water (of which most warm blooded animals are about 70% composition) is about 4960-5000 ft/sec, about 4.5x the speed in air. So that's the approx. propagation speed of the shock wave in the animal.