The Elusive Stopping Power "Formula" and ArmA 3

[Serclaes 0]

Well, they went down because of what? I can't think of anything else than kinetic energy being transferred quickly. But i agree that it doesn't mean they were fatally wounded. In fact I saw one deer getting up again after a shot to the chest with .223 Remington (5,56x45mm NATO).

But you're missing my point. My point is "KE can knock down targets, if it is getting delivered quickly. ie by softpoint instead of full metal jacket rounds."

Though as I said: a softpoint round with the same caliber needs more KE(either speed or mass) to go as deep as it's full metal jacket counterpart. But it would have created a bigger duct on the way.

Edited December 18, 2011 by Serclaes
grammar

[maddogx 13]

The average bullet packs a lot more kinetic energy than the average punch, and all energy has to go somewhere. If a punch can knock down a boar, so can a bullet.

[PuFu 4600]

^^ the difference is in the way it transfers the KE to the target.

[maddogx 13]

^^ the difference is in the way it transfers the KE to the target.

True, I guess some of the energy is absorbed (or whatever you want to call it) when the bullet penetrates the body, but assuming it doesn't go clean through, that's still a lot of energy that needs to go somewhere. On the other hand, a bullet that doesn't penetrate should transfer most of its KE to the target, and I'm fairly sure I've read somewhere that taking a bullet to body armor actually feels like getting punched, hard. :)

EDIT: Here a bullet impact to armor is compared to a baseball impact. ;)

Edited December 18, 2011 by MadDogX

[rye1 22]

Yeah, there can be many possibilities to why, and answers to your questions. But first of all animal anatomy is complex but it is not a good relation test when in reference to humans. You cannot always expect rapid incapacitation, shot placement is the key. KE cannot knock down a human or animal, it's not going to push or force them over, there are many scientific articles out there that can answer your question (Reference to Fackler, Gary K. Roberts, other wound ballistics experts... no internet wiseguys or your common youtubers).

Soft points expand, their peddles open up and flare like a flower and create a wider cavity and begin to slow. This normally clogs up the peddles with tissue and and aids in slowing it down. I see a bigger cavity being created, I don't see how energy helps kill a target within this.

What you're looking to do is cause damage to, within, and possibly away from the vital organs not transfer energy to the human body. If energy is transfered to our body then it negated and equalised as it transfers across the surface area, it has little to nothing to do with wounding or killing a target. It's not a 'punching' or 'pushing' motion. The only 'energy' you should believe in is the temporary cavity -- and even that does LITTLE damage.

A punch knocks down a boar? Oh yes?! Just as a punch knocks down a boxer? Are you sure it doesn't literally knock/shake the brain around in it's cushion. It's not stationary. The punch delivers the most KE but does the least damage; while the butcher knife does the most damage with the least KE, and the .22 short has about 50% more KE than the broadhead arrow but does much less damage.

While a bullet must have some KE--a bullet with no velocity does no damage--KE is a very poor predictor of a bullet's performance. Energy helps us get to a target, it helps open the peddles of a soft point or fragment a round, that's about where the similarities end in association with actually wounding somebody.

If it goes 'clean through', or through and through as the term is considered, then there is only a momentarily amount of energy transfer. It's negated by your body.

I'm going to bed :D. I told you topics like this without reference just stir up personal opinion, and so far most of my references have been scientific studies or from those who study the exact principles we talk about. Come back with an energy debate or study and I'll read it.

[Serclaes 0]

You're still missing the point.

We're not saying KE equals damage. We're saying rapid KE absorption equals stopping power.

[dysta 10]

You're still missing the point.

We're not saying KE equals damage. We're saying rapid KE absorption equals stopping power.

Simply say, the more energy it release when in instant, the more force (Newton).

[maturin 12]

I saw boars and red deers go down on impact. I really don't get his point.

We've all seen people lurch backwards from a static shock, a papercut, or a hot frying pan handle.

How much kinetic energy do you suppose was acting on them from those objects? Now what do you think they will do if they had their chest suddenly scooped out and scrambled instead of a little surprising zap?

People are fully capable of taking multiple .45 rounds to the torso (without over-penetration) without falling over. There's an article about just such a shooting somewhere online.

It's a matter of simple math that any normal small arms bullet isn't capable of knocking you off your feet if you really want to remain standing. You'd have to trip over your own legs, or be too busy getting shot to remember to keep standing.

Turns out people usually fall down when you destroy large portions of their vital organs, though.

We're saying rapid KE absorption equals stopping power.

You're putting the cart before the horse. Rapid KE absorption can only happen in one way. A bullet that is large or expands upon impact, creating a large or jagged temporary cavity. Contact with tissue slows a bullet down, and more contact will slow it down more.

So basically the only thing you said is that 'hollowpoints have stopping power,' dressed up in science-talk. The only way KE-transfer corresponds with lethality is when the shape of the bullet causes it to destroy more tissue and make a bigger, nastier hole. As a side effect of that, all its KE is "transferred."

Edited December 18, 2011 by maturin

[Serclaes 0]

There was a muscle memory reaction alright. It was "run like hell". Doesn't serve well when already knocked over though.

I know people can take multiple rounds. That's why soldiers prefer 7,62 over 5,56 and german police started using 9mm softpoint.

I just looked up "stopping power" turns out it doesn't entirely mean what I thought it means. What i meant to say is that a softpoint can knock over somebody easier than FMJ. I didn't mean to imply anything about lethality.

[-Coulum- 35]

Bullets don't knock people down due to the momentum or kinetic energy they transfer. It is simply due to pain, shock, reflexes etc. If a bullet was shot with enough momentum to knock a person off his feet, the recoil of the gun would knock the shooter off his feet as well.

As far as I know animals are able to take alot more damage than humans because they have a stronger survival instinct.

The effects of Kinetic energy released by the bullet in the form of hydro-static shock is not exactly known yet. Some say that the kinetic energy can damage organs far from the impact while others say it has no effect at all.

Wound size and depth and tissues hit however are known to be a factor in a round's ability to incapacitate someone. therefore I would rather have Arma's wound system based on this rather than on the inconsistent kinetic energy theories.

[froggyluv 2136]

Bullets don't knock people down due to the momentum or kinetic energy they transfer. It is simply due to pain, shock, reflexes etc. If a bullet was shot with enough momentum to knock a person off his feet, the recoil of the gun would knock the shooter off his feet as well.

As far as I know animals are able to take alot more damage than humans because they have a stronger survival instinct.

.

Agree with "pain,shock,reflex" being a huge determining factor. People simply react differently to both the flood of adrenline and pain/shock. Some feel nothing, some go into flight, some into attack and others drop and ball up.

One thing I think may drop people is getting shot in a large leg bone ie. femur and obviously the spine.

[rye1 22]

Damn, you post something off someone who studies this day after day, who runs a Trauma clinic and deals with live gun shot wounds literally every week and is employed by the FBI for exactly the same reason and this is what you get. Reality is we should listen to the facts, not opinions, mechanics and proven facts of wounding not theories of how something may wound or not proven possibly fictious creative stories based on little to no academic research or flawed research.

Simply say, the more energy it release when in instant, the more force (Newton).

He would still be wrong because "force" isn't killing or wounding someone, reality is more of a cutting motion through flesh than this theories punching motion. We don't absorp energy we lessen it's affect over a larger surface area (

). To put it in an easy to understand context: my fact vs this theory and that only!

Who would do the most damage? My fact. Energy does zip wounding damage and if you solely relied on it you would be wasting ammunition :p. THEREFORE, why add it to a game? It's useless. BIS would be wasting their time on a so called formula. Go with facts, and things that actually cause damage! Don't get lost in other dribble.

We're injured by what the bullet does to us, not the energy it used to get there.

So now we've got that out of the way Serclaes, thank you!

@-Column- Exactly but IF it was damaging organs far from the impact point it would be minimal, and therefore unworthy of being in game. Energy dissipates. Unfortunately as the poll shows many agree with stupid theories and not fact of wounding mechanics.

Things that should be changed on the poll:

Bullet Mass (heavier and larger rounds; sectional density steps in)

Bullet Caliber (bigger bullets create wider wounds)

Bullet Shape/Form Factor (affects external ballistics, range vs wounding capacity (sometimes it doesn't even matter on distance to kill))

Penetration, Wound track path (overpenetration causes a larger exit wound, underpenetration enough to reach vitals?)

Performance vs. armor (energy dissipation vs a hard armoured surface is different to human tissue, which is flexible in comparison)

Other key aspects of wound ballistics (expansion, fragmentation, yawing, etc.)

What anatomical structure was hit, including organs; importantly the Nervous System

Something else not mentioned here (Please post)

[-Coulum- 35]

I agree with you rye. The theories connecting kinetic energy to stopping power are quite shaky. As for those who still think that kinetic energy delivered by a round is a bigger factor than things like wound size, depth and shape consider this. Why are bullet proof vests useful? Is it because they stop the person being hit from receiving the energy of a round. No, they don't really decrease the energy being transferred by a shot, merely spread it out. Bullet proof vests are useful because they stop the bullet from making a wound and ripping tissue.

Another. What would you rather get hit with. A hollow point dum dum type round or a solid slug of the same dimensions and speed. Most would rather the solid slug because it doesn't mash your insides up quite as much. But if we were going by which delivers more energy the solid slug, which would weight more due to its lack of hollows, would apparently be more lethal because it is heavier and therefore carries more energy. That doesn't make sense as fragmenting rounds have been known to cause massive wounds and bleeding which are often lethal.

the stopping power of a round in my opinion is its ability to cause the most pain which in turn will cause the target to drop and stop fighting. usually, more pain is caused by bigger deeper, irregular wounds. therefore larger calibers, fragmenting, yawing, and the speed of the bullet should all be taken into account when calculating the severity of a shot, not energy.

When it comes down to it however the thing that matters most is the location of the hit. I would actually be willing to go so far as to say that instantaneous stopping power is strictly dependent on the location of a hit, and that the wound size, fragmentation, depth etc. would only contribute to bleeding and pain, which could result in near instantaneous incapacitation. ie if you shoot someone in the head it is instantaneous death/incapacitation no matter what round is used. If you shoot someone in the arm however no matter what round it will not result in instantaneous incapacitation. If this was a shot from a pistol however you would be able to fight on for a while before you pass out from blood loss, or pain, or simply give up. If that shot was from a 50 cal however you would take the round and give up in less than a second due to the pain - not totally instantaneous but pretty damn close. The time it would take would be based on the pain caused (which is in turn dependent on calibers, fragmenting, yawing, and the speed of the bullet) and be slightly randomized to account for people having different pain thresholds. just an idea. What do think of it?

Also rye I think it is great that you actually cite what your stating unlike me and most others. I actually feel I am learning something reading your posts.

[pvt_ryan 10]

Haven't been able to read every last post yet about people's concerns regarding the kinetic energy theory's ability to predict stopping power (although I do understand the criticisms), but the question beckons- how else would you simulate it? Sure, you say wound depth and size, etc. but how do you predict that? I mean, surely you don't actually test guns performance (even on ballistic gel) so how exactly do you represent that in a numerical format that a computer program can understand? Randomness, or what? and more difficult, how do you simulate this in a way that demonstrates the disparities in different rounds' performances over range? At some point I feel like you either have to go off experimental data (which of course is much more expensive and time-consuming), or accept a flawed theoretical formula for what it is.

[rye1 22]

Well first fixes for the engine such as hitdetection, blah, blah. Making those kind of scripts more accurate would be a big help. I suppose MP issues would be closely related with this.

As Tom1 said in a post a while ago, you could just account for new wounding capacities through new scripts and make it into a one number formula on the hit ratio.

Or you could go insane, lock yourself in a BIS dungeon and work on something crazily innovative like a world of tanks type system on a human model.

(I'm sure there's more options, but creativity is flawed by realism and what BIS can do with the engine :D)

[pathetic_berserker 4]

He would still be wrong because "force" isn't killing or wounding someone, reality is more of a cutting motion through flesh than this theories punching motion.

Though you are more correct to say so, I there is actually some effect from the change in energy or 'impulse' as its termed. Not only is it a defining factor in how the bullet material meets your other critera it can also causes shock waves through tissue which can have some realy nasty effects.

Kind of why I dont see the point in chasing the science too much on this and looking for the holy grail that translates it. No matter wich way you look at it, whether you start with the bullet and chase it or try reverse engineer from its final resting place, the science itself says it's realy too hard to perfectly predict.

BTW Ryan I don't in any way mean to discredit your excelent explanations. Just see why many peple get confused coz not all KE is alike.

Edited December 22, 2011 by Pathetic_Berserker

[rye1 22]

You failed to give me a reason or any proof, only a theory that didn't make much sense. I said if you came back to me with something I could read then fine but...

What change in energy? How is it a defining factor? What "nasty" effects? Because there are only secondary effects to the proven wound mechanics given. You have only created more questions than answers. Science, anatomy and solid research has been leading the way on it, if you took more time to read it maybe you'd think differently to it.

Energy isn't a defining factor, it's the primary one to get to the target though. It's called velocity. The vast majority of this is lost on impact with an object. And if the theory was correct then much of the KE wouldn't even be transfered to the target and over distance less energy, less chance to kill (which by all long range kill accounts has been false). Again, if it was correct, the pressure wave would only cause secondary damage; and as 'energy' tests have revealed that it tends to be minimal:- they like to go off some data, then exaggerate theories of well based on this, it could do this, i.e. if it entered close enough to the brain stem, pons, medulla oblongata etc then it could kill or incapacitate a target or even cause some widespread rumours not confirmed in humans like brain hemorrhaging. If this is true, then so be it, then why should it be in game? No good reason, we should not solely rely on that apparent form of 'wounding'.

What are you more worried about?

http://www.firearmstactical.com/images/Wound%20Profiles/Wound%20Components.jpg

The energy being dissipated along your body surface...

Or

The bullet tearing through your skin. :D

What would you treat as a medic/paramedic/whatever?

[pathetic_berserker 4]

Um... without KE the bullet does nothing.... literaly.

And I've seen holes big enough im myself to revleal bone and realy have no definable answer for you, coz its always in the aftermath, ie would I prefer to take a lucky hit from a very hard very fast object that passes entirely through me leaving a few simple holes or a larger slower object that leaves a wide messy wound path and possibly shatters a bone or two.

Point is, to determine any of the other factors you have to know its KE because energy is ALWAYS conserved. The bullet cutting flesh dosen't happen just because its a bullet. It happens because it has the KE to push through your flesh.The penetration of said bullet is dpendant on its shape and area and its structural integrity as this determines the rate at wich its 'kinetic' energy is disapated, the higher the energy, the longer it takes, the smaller the area the longer it takes.The shorter the time it takes to stop the bullet the higher the rate of energy change or 'impulse'. The width of the temporary cavity you showed in your last post is also very depandant in the change in velocity (or 'Impulse' or change in energy)

As long as the bullet is in motion, be it in the air or in your body, it is coverered by the field of study called Kinetic Energy. Which is why I'm a little confused by some of the statments I see, Because they appear to argue along the lines that its not the height that kills you its the fall, no its not the fall its the landing blah blah blah,

If you make the statement that KE has nothing to do with the resultant wound then you have no idea what KE is.

[dysta 10]

First of all, what makes the bullet can "push" the target? The answer is the dimension of contact. Why the softball can shatter a whole glass, while the rifle bullet can only make a cracked hole on it, the reason is the lack of the kinetic release at the whole object when it's penetrating, while the softball can form into a massive contact area when in impact with force.

So to say, it's not about how much the KE to push the bullet, but instead how much the KE the bullet can release at the CONTACT AREA (Not into the target, it won't work when it's already hollowed in).

[pathetic_berserker 4]

So to say, it's not about how much the KE to push the bullet, but instead how much the KE the bullet can release at the CONTACT AREA (Not into the target, it won't work when it's already hollowed in).

Well and good but the effect doesn't exactly cease just because the bullet is just under the skin its defined more by its rate of deceleration.

Sorry if i didn't make myself clear enough before and I know this is a bit like the rest of the thread wich is a little off the topic of 'stopping power' but I think much of the misunderstanding I see is because peope using the term kinetic energy a bit wrongly. Kinetic Energy is the field of study that encompasses things such as velocity, impulse, momentum, acceleration, deceleration, speed, bacicaly any body or object in motion, so as long as its it's actualy moving KE plays a part, can be measured and can be used to derive measurments.

[rye1 22]

As I said. Energy is what it takes to get to the target. I didn't say it did nothing.

That wider mess is because when it slows it has less stability, the nose sometimes dips in and you have a wide cavity as well as fragmentation. You can see this happen in many ballistic gel videos.

We change to a whole new study; it's called Wound Ballistics - because you don't rely solely on energy to kill someone. As said 1,000 times. Think of all the wound mechanics... permanent cavity, fragmentation, expansion, entry and exit wound... I don't give two shits about energy I give a shit about what is causing damage. Again, nothing to do with KE - KE isn't causing primary damage, it is not killing you.

I think you're the one with the misunderstanding -- the whole wound ballistic energy debate is on energy being the primary factor of killing/wounding you.

http://www.rathcoombe.net/sci-tech/ballistics/myths.html#energy

[maturin 12]

You can tell the KE crowd is full of shit because of the terms they use.

"Hydrostatic shock" is an oxymoron. No physicists actually use terms like 'energy dump.' Much less "deposition" of KE. Deposition? Are we geologists now?

[pathetic_berserker 4]

Think of all the wound mechanics... permanent cavity, fragmentation, expansion, entry and exit wound... I don't give two shits about energy I give a shit about what is causing damage.http://www.rathcoombe.net/sci-tech/ballistics/myths.html#energy

You still don't get my point. I don't have a problem with your argument in general terms. I have a problem with the way you use the term Kenetic Energy. All those mechanical effects you just rattled off require kinetic energy to fuction. As soon as you say KE is irrelevant you lose all scientific basis. It may sound like semantics but science is. The term a physist would use for the effect your disputing is Impulse.

So personaly I don't think many of articles you have quoted have any more scientific basis than the people they are trying to dispute. And the only room I see for study here is how observation turns into anecdotal evidence, turns into myth, turns into quasi science types getting bees in thier bonet and shouting your wrong!

Need to bring this back to being game relevant.

Edited December 22, 2011 by Pathetic_Berserker

[rye1 22]

You're not making a point in reference to wounding mechanics. You're saying energy is in everything that happens, point? It's not wounding people. Therefore it should not be in a game. If it was it would need a kinect energy formula to do X, Y, Z and become totally useless. Velocity; we've got it already and that's all we currently need.

On a scientific basis in relevance to wound ballistics then KE does some things but has limited to no affect on wounding characteristics, and for those that believe in some KE theories then it still would be a secondary wounding mechanic. You're trying to dispute something that Wound Ballistics Experts, anything from Doctor's to Scientist's, have already discussed and researched a hundred times over.

The hydrostatic shocks theory, energy dump theory, your impulse theory. Even if it existed it would be doing secondary damage. But as stated, the transfer of energy is not a wounding mechanism. It is not on the same par of wounding than what I've already discussed.

Kinetic energy can tell us how much a projectile might overcome in terms of tissue, if we know surface area of the projectile and the resistance value of the tissue being fought (figuring it takes a certain amount of energy to traverse 1 cm of tissue), so it gives us some idea of penetration factors (and that matters when trying to get to the vitals).

When looking at wounding characteristics, kinetic energy doesn't tell us much of anything comparative to actual destruction of tissue.

So, if you want game relevant information; you account for vital organs using hit detection, you account for damage indicators such as fragmentation (yes, this relies on energy-velocity to actually fragment). A few scripts that will make wounding a lot more realistic and you are using proven ways to incapacitate, kill or wound--NOT theories.

[pathetic_berserker 4]

Still no real argument from me except it isn't 'My' impulse theory, is something taught in first year physics. So any time someone tries to write off KE I question wich bit of KE they are really talking about.

I think the biggest problem with the question being asked is that it becomes a statistical analysis where the data for most of the events is unknown or imprecise.

As far as I can see the only true scientific method would be to take at least 200 (considered a scientificaly relevant number) people of approximately the same build give them a full medical and MRI scan then shoot each one aiming for the same point under the same circumstances then analyize the result. Of course this would also have to done for each bullet type at various ranges, different hit locations and so forth. Naturaly anyone who thinks this a good idea is a prime candidate for being one of its subjects.

Secondly once we take all this 'best we got' statistical data we have to come up with a way of plugging it back into the game wich will imvolve a formula, and probabaly a fair bit of theorising as to how to achieve parity with the statisics.

see what I'm saying yet.