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Bullets: How Many Energy (Joules) To Kill?


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#1 istvan47

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Posted 01 November 2012 - 0622 AM

I mean, what's the limit for harm an human being? The 7.62 NATO is an overkill. Parabellum is powerful, 22 LR is weak, but still lethal at very close range. The relative energy is around 4,000, 400 and 100(?) Joules. So how much energy is needed to harm seriously someone?

Did someone survived to a 0.50 caliber (M2/DSHK)?

#2 Jason L

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Posted 01 November 2012 - 1157 AM

Some guy in the sandbox survived a HMG hit to the head, although the round was balistically spent. There are literature sources reporting survived hits to limbs from .50 cal projectiles.

Energy is in many ways a poor, but ease metric but it's useful in statistical analysist

The Pk of a hit from a missile scales with energy for personel in the open:

Pk of 10% = 0.1 kJ
Pk of 50% = 1.0 kJ
Pk of 90% = 4.0 kJ

Note these are for statistical models and are thus pretty rough and from an old US FM. Different people use different numbers with different rationals.

The basis of the US rational is that 0.1 kJ is a .22 LR which a sort of "minimum" man killer, 1.0 is a .357 mag, and 4.0 is about a 7.62mm

I would be interested if anyone has data on survival rates for non-SCHV ammo. 90% kill when hit seems a touch high to me.

Edited by Jason L, 01 November 2012 - 1157 AM.


#3 istvan47

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Posted 01 November 2012 - 1254 PM

then, 100 joules are the 'minimum' needed to harm a human body?

Once i read that someone was shot in the head 6 times (in the USA, i mean), and still managed to survive with just 'minor injuries', maybe it was hit by a 22 LR?

#4 Delta tank 6

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Posted 01 November 2012 - 1305 PM

I mean, what's the limit for harm an human being? The 7.62 NATO is an overkill. Parabellum is powerful, 22 LR is weak, but still lethal at very close range. The relative energy is around 4,000, 400 and 100(?) Joules. So how much energy is needed to harm seriously someone?

Did someone survived to a 0.50 caliber (M2/DSHK)?


A lot depends on where you are hit.

Mike

#5 Doug Kibbey

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Posted 01 November 2012 - 1834 PM


I mean, what's the limit for harm an human being? The 7.62 NATO is an overkill. Parabellum is powerful, 22 LR is weak, but still lethal at very close range. The relative energy is around 4,000, 400 and 100(?) Joules. So how much energy is needed to harm seriously someone?

Did someone survived to a 0.50 caliber (M2/DSHK)?


A lot Everything depends on where you are hit.

Mike


I've seen survivors of a .50 cal hit, and there are plenty of people who have succumbed to .22 rimfire hits. The OP question which (ostensibly) tries to put incapacitation into a pure energy equation w/o regard to the area hit, the size and robustness of the target and any mitigating factors (body armor, thick clothing, will to overcome) is effectively meaningless. It's exactly the sort of question one would expect from a tweenager, which wouldn't surprise me to find out is the case.

#6 rmgill

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Posted 01 November 2012 - 1904 PM

Location, location, location.

#7 Jason L

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Posted 01 November 2012 - 2021 PM

I've seen survivors of a .50 cal hit, and there are plenty of people who have succumbed to .22 rimfire hits. The OP question which (ostensibly) tries to put incapacitation into a pure energy equation w/o regard to the area hit, the size and robustness of the target and any mitigating factors (body armor, thick clothing, will to overcome) is effectively meaningless. It's exactly the sort of question one would expect from a tweenager, which wouldn't surprise me to find out is the case.


Doug, with all due respect, you don't have any idea what you're talking about with that statement. It all depends at what level you want your model to work at. For modelling Pks of warhead fragments a purely fragment kinetic energy Pk is generally deemed sufficent.

Modelling abstraction is perfectly fine as long as you know the limitions of the abstraction. Pk should broadly scale with energy as the ability to defeat protection scales with it as well, as does the degree of wounding at a given spot (very roughly anyway) and impact location is also stoichastic so that can be corrected for seperately.

#8 toysoldier

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Posted 01 November 2012 - 2112 PM

I gather that with headshots the probability curve kinda changes.

#9 Jason L

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Posted 01 November 2012 - 2213 PM

I gather that with headshots the probability curve kinda changes.


Why does it matter? You're talking about an aggregate risk that inherently includes anatomical distribution in where people get hit. Also head/neck wounds are weird: they kill more outright but there are more living WIAs with head/neck wounds than with abdominal wounds.

And either way, a pistol calibre round is less likely to kill someone with a head/neck hit than a higher energy missile.

#10 Doug Kibbey

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Posted 01 November 2012 - 2239 PM


I've seen survivors of a .50 cal hit, and there are plenty of people who have succumbed to .22 rimfire hits. The OP question which (ostensibly) tries to put incapacitation into a pure energy equation w/o regard to the area hit, the size and robustness of the target and any mitigating factors (body armor, thick clothing, will to overcome) is effectively meaningless. It's exactly the sort of question one would expect from a tweenager, which wouldn't surprise me to find out is the case.


Doug, with all due respect, you don't have any idea what you're talking about with that statement. It all depends at what level you want your model to work at. For modelling Pks of warhead fragments a purely fragment kinetic energy Pk is generally deemed sufficent.

Modelling abstraction is perfectly fine as long as you know the limitions of the abstraction. Pk should broadly scale with energy as the ability to defeat protection scales with it as well, as does the degree of wounding at a given spot (very roughly anyway) and impact location is also stoichastic so that can be corrected for seperately.


Jason, with no respect intended you shouod know that modeling these effects depends on an agreed set of parameterd where are nowhere to be found in evidence.There is agreed basis of modeling abstraction as evidence by the sheer volume of alternate interpretaions bases on mass, velocity and effect in terms of terminal ballistics. Thew entire internet almost collapses under the force of it's own gravity trying to find amount of energy will yield a particular level of damage and to date, no such agreement has been reached. Istvan seems to be searching for an unreal number that realiably yields a predictable and reliable result while controlling as few variables as possible. This isn't "modeling"...and isn't even guesswork. It's pure speculation based on number taken out of context and applied randomely to yield a comclusion that escapes me. I'd recommend that both you and he start over and try to decide exactly what anwer it is that you are seeking, and then how to best go about finding the calculation that will satisfy it. Given the many attempts that I've seen over the years, I wish you the both the very best of luck in that endeavor. I doubt you have any idea of how complex a question you are asking, and are patently the least equipped persons to address it. But bet of luck to you both. The must be countless websites, militaries, industroes amd police forces out there breathless awaiting your conclusions. I admit that I'm looking forward to them myself.

#11 Jason L

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Posted 01 November 2012 - 2330 PM

Jason, with no respect intended you shouod know that modeling these effects depends on an agreed set of parameterd where are nowhere to be found in evidence.There is agreed basis of modeling abstraction as evidence by the sheer volume of alternate interpretaions bases on mass, velocity and effect in terms of terminal ballistics. Thew entire internet almost collapses under the force of it's own gravity trying to find amount of energy will yield a particular level of damage and to date, no such agreement has been reached. Istvan seems to be searching for an unreal number that realiably yields a predictable and reliable result while controlling as few variables as possible. This isn't "modeling"...and isn't even guesswork. It's pure speculation based on number taken out of context and applied randomely to yield a comclusion that escapes me. I'd recommend that both you and he start over and try to decide exactly what anwer it is that you are seeking, and then how to best go about finding the calculation that will satisfy it. Given the many attempts that I've seen over the years, I wish you the both the very best of luck in that endeavor. I doubt you have any idea of how complex a question you are asking, and are patently the least equipped persons to address it. But bet of luck to you both. The must be countless websites, militaries, industroes amd police forces out there breathless awaiting your conclusions. I admit that I'm looking forward to them myself.


Umm right. Well if you actually bothered reading in the right places you'd find that there is actually an extensive body of literature on the subject of Pk modelling of casualties from missiles, do you think I pulled those numbers out of a vacuum? They are from a USDOD publication. The internet is mostly full of average people, and so I'd wager it's a relatively useless metric in the success and viability of the "endeavour", and a largely immaterial once since it's already been done to varying degrees of success while the internet has been busy doing whatever it does (ie not much).

There are lots of things we know extremely well. We know the stress and strain rates required pierce various biological materials and how that varies with the parameters of a human. We know the penetration behaviour of these materials well enough to extract a meaningful minimum class of missile that can stand a decent chance of killing a person. Missiles fired from firearms and explosively launched have very specific ranges of masses and velocities which means you can then extract at least a somewhat meaningful "energy" term. There are then a whole slew of other factors, parameters, etc, factored in, but the specific question was about energy

I didn't come up with this stuff either, other smart people have after collating data from wars spanning the ACW to OIF/Afghanistan.

There are of course ample problems with the models and constant refinement and the problem is indeed extremely complex. In case you didn't notice though, smart people solve extremely complex problems often enough. And anyway your determined ignorance and horrible ability to judge character isn't my problem. If you're approach to any complex problem is to say ""it's impossible, there are lots and lots of people way out of your league already.

Either way, there is ample literature available to suggest than the Pk of a missile (bullet or fragment) with a kinetic energy of less than 100 joules is quite low. This isn't exactly a religious revelation. I would submit there is no perfect answer for the Pk as a function solely of missile energy along the full range of possible missile energies but there are already provably ones that reproduced observed trends well enough for government work.

Edited by Jason L, 01 November 2012 - 2336 PM.


#12 TTK Ciar

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Posted 02 November 2012 - 0035 AM

First:  Lethality is complex -- http://aux.ciar.org/...ackler.unk.html

Second: Ivanhoe recently suggested bullet momentum (mass times velocity) is a more meaningful metric of wounding potential than bullet kinetic energy (mass times velocity squared), and I'm inclined to agree with him -- http://208.84.116.22...60

Edited by TTK Ciar, 02 November 2012 - 0035 AM.


#13 Jason L

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Posted 02 November 2012 - 0120 AM

First: Lethality is complex -- http://aux.ciar.org/...ackler.unk.html

Second: Ivanhoe recently suggested bullet momentum (mass times velocity) is a more meaningful metric of wounding potential than bullet kinetic energy (mass times velocity squared), and I'm inclined to agree with him -- http://208.84.116.22...60


The statistics of lethality are much simpler than the physics of lethality though. Strength in abstraction and all that.

Momentum is a better indicator of penetration at ordinance velocities, but penetration /= lethality. Both momentum and energy have problems. Momentum over-emphasizes the value of mass and de-emphasises the effect of expansion, fragmentation and temporarity cavity effects. Energy does exactly the opposite. Both have problems and both ultimately neglect the fact that lethality is really some function of the depth of penetration and the volume of damaged tissue.

For projectiles with limited temporarity cavities, a better metric than either momentum or energy is some function of depth of penetration and projectile diameter.

Certainly for discussing the lower limit of what constitutes a "probably lethal" projectile the issue boils down being able to appreciably pierce the skin and some depth of tissue. That's related to interface pressure and strain rate, and so momentum becomes a very poor measure for that threshold since you can apply very large momentum without being appreciably lethal. Energy emphasies the threshold criteria which is velocity, without neglecting the importance of mass

For general missiles, energy is attractive for reasons of how fragment distribution are handled.

#14 Tony Williams

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Posted 02 November 2012 - 0244 AM

To answer the original question - the minimum energy associated with killing a human being is less than 5 joules (an air pistol, fired through the eye and into the brain at close range).

#15 nigelfe

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Posted 02 November 2012 - 0300 AM

Have a look at the fragmentation section on this http://nigelef.tripo.../wt_of_fire.htm page of my web site. Oviously fragments can have much higher velocity that bullets and being irregular shaped transfers force more efficiently. The data for the UK WW2 reseach was derived from bombing casualties in UK and battle casualties.

#16 Sikkiyn

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Posted 02 November 2012 - 0300 AM


I mean, what's the limit for harm an human being? The 7.62 NATO is an overkill. Parabellum is powerful, 22 LR is weak, but still lethal at very close range. The relative energy is around 4,000, 400 and 100(?) Joules. So how much energy is needed to harm seriously someone?

Did someone survived to a 0.50 caliber (M2/DSHK)?


A lot depends on where you are hit.

Mike


Figure my arrow, at 50m, may roughly generate 625J (but people throughout history have survived, though many haven't either).
In contrast, my tanker at 80,000, at cruising speed = P =mv = (36200 kg)(26.82 m/s) = 971,000 kg/ms
Energy would be 1/2mv^2 = .5(36200)(26.82)^2 = 23,016,000 J of kinetic energy, yet by some weird twist of fate, divine blessing, etc, people have survived being hit by a heavy truck at cruising speed.

Now take a person who simply trips and falls, but yet we hear stories from time to time of someone dying just from that.

As pointed out it is all about location, timing, distance, and fate.

#17 iamcanjim

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Posted 02 November 2012 - 0336 AM

One of the guys on my gun forum bet that he could catch a .22 short at 200 yards with a leather glove. It penetrated the leather glove and hand.

#18 Mr King

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Posted 02 November 2012 - 0905 AM

One of the guys on my gun forum bet that he could catch a .22 short at 200 yards with a leather glove. It penetrated the leather glove and hand.


"Hey yall watch this"

#19 thekirk

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Posted 02 November 2012 - 1303 PM

If you want to argue the issue, you have to first include a bunch of variables that the DOD has left out, simply because of the complexity involved in modeling. Sure, they know precisely how much energy it takes to penetrate a given amount and type of tissue, but then what? How to account for the "X" factor that leaves some men going "OHMYGAWDIMHIT!!IMGONNADIE!!!", and collapsing completely into helpless shock followed by death, while other men with similar hits are found after beating their assailants to death with their own weapons asking "Wait... You mean he hit me?". Attitude, adrenaline, and a whole host of other intangible issues go into answering that question of what it takes to kill someone, let alone someone amped up on adrenaline in combat.

Due to this, I think we ought to be working from the backwards end. First, figure out what's going on out on the pointy end, which would mean recovery of enemy bodies or those of our own who are shot by weapons of our own, and then do the backwards tracking: What did the projectile actually do, and how long did this individual stay in action afterwards? Rudimentary data capture should be available from UAV footage, and with a bit of battlefield forensics, we should be able to get an idea of what's sufficient. Right now, we've got all kinds of data saying such-and-such does this, but the relevancy to what we need on the battlefield isn't established because we haven't taken that final step of finding out how the actual issued rounds are working in actual enemy targets. Up to the present day, gathering such information was problematic, but with modern technology and battlefield surveillance, getting the real-world data should not be an insurmountable step. We just need to take it.

There's a world of difference between what "should work", based on laboratory work, and then what does work in the field. There was a short-lived phenomena of the 147-grain slow hollowpoint for 9mm, which worked wonderfully well in many simulations and calculations. Turns out, however, that that round didn't work as well as they thought it would, and the majority of police went back to the traditional 115-grain weight with more modern projectiles. In order to validate science, you have to avoid building airy-fairy castles in the sky, and inject a healthy amount of real-world data and experience back into the process. We haven't done that in regards to what we're issuing the troops. I'd submit it's probably time we did so.

I'd also suggest that it's time to take another look at the Hague conventions about expanding rounds, and consider changing the rules. I'd rather incapacitate an enemy with one or two shots that do major damage, than to poke him full of holes that a.) don't really stop him from what he's doing, and b.) make it a lot harder on the medics if he does live. If it's considered inhumane to use FMJ on game, why the hell haven't we made the connection to warfare? And, note well, I'm not talking about using glass or plastic rounds that disintegrate, either--Simply making sure the mechanism we're using to stop/incapacitate the enemy is effective and as humane as possible. Having seen the aftereffect of someone hit by 15 or so rounds of 5.56mm, I'm not of the opinion that that cartridge is really a good choice for shooting people with. As it is, I suspect it's on the ragged edge of the "effective/ineffective" break, and that the odds are very good that it's only effective under ideal conditions of where it hits, and what it hits.

#20 Simon Tan

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Posted 02 November 2012 - 1322 PM

If you believe a number has some magic threshold, there's some nice seafront property I'd like to sell you in New Jersey. You cannot imagine how ridiculous 4.6x30 looks....it will kill you deader than dead with a little judicious placement.




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