How much damage do bullets do?

[Gnalvl 1]

To clarify, I'm not suggesting that it should be impossible to die from extremity shots. On the contrary, I would say that a shot to any part of the body should have a chance to kill you. However, there is a huge difference between real life deaths from extremity shots, and videogame insta-deaths. Even if we take one of the most brutal real life extremity shot deaths as an example: a shot to the femoral artery, which can bleed you out within 30-60 seconds, that still allows a gigantic window in which the victim might continue letting loose stray fire at his attackers.

By comparison, if you attempt to carry this over under a conventional videogame damage system, you just wind up with soldiers that die instantaneously, the second they are hit anywhere. Arcade apologists will tell you that the solder isn't really dieing instantly from a leg wound, they are merely being "incapacitated" and bleeding to death gradually...but the game already counts them as dead because they "can't" fight. It's a poor excuse; this system is a simplified representation of reality which entirely removes the risk inherent in real life combat. Any reputable source will tell you, shots which don't damage the central nervous system don't guarantee instantaneous incapacitation. Without the possibility that the enemy could continue firing for 1,2, 3, 5, 10, or 30 seconds after a lethal extremity shot, then all a "one shot can kill" mentality does is promote twitch shooting mechanics; "I can go rambo because I know if I round the corner and shoot them first, they can't get me".

[rye1 21]

actually, people died from getting shot in the extremities all the time

in Vietnam War alone, about 2,500 US soldiers died from nothing but extremities injuries.

another research concluded that 9% of combat death result from extremities bleeding, hence called "the most preventable death" by TCCC courses.

http://mhs.osd.mil/Libraries/120917_TCCC_Course_Materials/020401-Intro-to-TCCC-IG-120917.pdf

Bled to death, not outright died from the shot to an extremity. We were talking about in ARMA how people can die from five shots to the hand. Which is equals to say two shots to the chest.

People lose arms, legs. It's been known for 7.62 to penetrate around the radial head, tearing apart ligaments and taking off an arm. Hemorrhage control is a major factor to life-saving. It's tough when you're dealing with extremities, especially the legs as you can have the large mass of the thigh which usually needs two tourniquets, squashing all that tissue like a mattress trying to compress the femoral artery plus finding bleeding origin can be impossible. It could be from the abdominal aorta, hence why the CRoC and pelvic splints were successful interventions.

Seeing how that article being 2012 hasn't come a long way from this one in 2000.

"KIA 31% Penetrating Head Trauma

KIA 25% Surgically Uncorrectable Torso Trauma

KIA 10% Potentially Correctable Surgical Trauma

KIA 9% Exsanguination from Extremity Wounds

KIA 7% Mutilating Blast Trauma

KIA 5% Tension Pneumothorax

KIA 1% Airway Problems

DOW 12% (Mostly infections and complications of shock)

[KIA: Killed in action

WIA: Wounded in action

DOW: Died of wounds]

PREVENTABLE Causes of Death on the Battlefield

Bleeding to death from extremity wounds (60%)

Tension pneumothorax (33%)

Airway obstruction (maxillofacial trauma) (6%)"

Then we can only imagine the setting ARMA 3 is in. Medical advances, combat first aid but we're still dealing with projectile weaponry, and 'better' rounds.

1) Precise Center Mass Hit Detection

2) Non-Instant Incapacitation

3) Randomization

Yes, straight away discard temporary cavity. Sure it can 'cause' some temporary and usually low-scale happenings but it's not a damaging factor for the most part. You don't want to account for those variables, I mean displaced muscles, who cares? And if you compare FMJ to AP rounds and similar you'll note that AP rounds tend to go through and through in most cases so if ammunition variety is seen in ARMA then there's logical reasoning for the change of damage values through the selection of ammunition types. The 5.45 is known as the poison bullet for good reason. Throw precession into the mix and its axis can literally turn upwards and those kind of rounds really stand out.

To your points:

1. Precise Center Mass Hits.

Well, if you think about it with the new gear system and the accountancy for 'armor' then this would be nullified. I don't know how that would work. Chance of penetration?

2. Non-instant Incapacitation Shots.

I agree. It's stated in many LE wound ballistic articles that a number of those shot in a firefight actually bleed out elsewhere other than the position they got shot from. They normally get to cover and away from the area before bleeding out, going unconscious and so on. Weighing non versus lethal is all about hit detection and how the damage values are utilize though.

ACE tries doing similar in terms of bleeding to unconsciousness. The more movement, the more you bleed, the more pain you have and so on.

3. Randomization.

I agree randomization and chance is always good to have, we're including it in CMS but it depends what kind of values you're looking at for what kind of factor.

[dnk 13]

I've modded in vast overhauls of health in other games. The way I usually do it is to severely limit the actual bullet damage, then set bleeding as the primary killer. A way to do it in Arma would be:

Low initial damage, each cartridge has an intrinsic damage and bloodloss coefficient.

Each limb has "normal" and "critical" damage possibilities, measured by likelihood of being shot in soft tissue or being shot in an artery. Additional possibilities for limb disablement from severe bone/nerve damage.

Torso/chest/neck/head have special system of "normal" and "critical" damages. "Critical" now has an additional randomization between "severe bleeding" (shot to liver, spleen, lungs, major arteries), "extreme bleeding" (shot to heart/aorta), and "paralysis" (shot to spine/brain = instant death in-game). Being shot forces an odds roll which then determines the nature of the wound (so, shooting someone point-blank in the heart doesn't at all mean they're getting "extreme bleeding", the random roll may turn up as a "flesh wound").

Obtaining the percentages is simply a matter of mapping the human body (from 1 or 2 axes) and seeing what %age of each of BIS' distinct regions is appropriate for each type of wound.

The hard part of this system is figuring out how long to make it between when someone starts, say, bleeding from the brachial artery, and when they are effectively "out of combat" as an incapacitated wounded (and then how long before fully dead after that). This would require a balancing between real-world stats (which perhaps you guys have - I see one for the femoral artery) and gameplay (perhaps, perhaps not). If you do have any numbers to go on for the various types of wounds, I would appreciate it, as I would like to mod this into A3 as well.

This creates a multi-tiered health system of:

1. Fully healthy
   
2. Light bleeding (flesh wounds)
   
3. Heavy bleeding (arterial, blood organs)
   
4. Loss of limb function (bone or nerve injury)
   
5. Incapacitation (rolling on the ground, unconscious but revivable (but still may die regardless), in shock)
   
6. Death/out of combat (bleed out, CNS paralysis/damage)
   

Additionally, first aid can be applied (as in ACE2) which will limit bloodloss (partially or fully, but not regenerative). This, in addition to reviving incapacitated soldiers (again, as in ACE2) becomes the role of medics. Currently, they're fairly pointless to have given the extreme lethality of the game.

[4 IN 1 0]

Just wondering, is the ammunition behavior still only depending on ammunition config or does different weapon also have value in their config to affect ammunition behavior?

[Gnalvl 1]

Yes, straight away discard temporary cavity. Sure it can 'cause' some temporary and usually low-scale happenings but it's not a damaging factor for the most part. You don't want to account for those variables, I mean displaced muscles, who cares? And if you compare FMJ to AP rounds and similar you'll note that AP rounds tend to go through and through in most cases so if ammunition variety is seen in ARMA then there's logical reasoning for the change of damage values through the selection of ammunition types. The 5.45 is known as the poison bullet for good reason. Throw precession into the mix and its axis can literally turn upwards and those kind of rounds really stand out.

Yeah, I mean temporary cavity could have a role in a few specific things, but you'd need to model permanent and temporary damage as 3D space with volume, rather than as points, and as well as model individual organs. In that case, if the temporary cavity area intersects with inelastic organs like the liver, spleen, or kidneys, that could be counted as additional permanent damage. There is also a speculated stun effect from temporary cavities impacting the spine, I would be ok with things like screen blur, camera flinching, etc resulting from such hits - in general I might expect a bullet like 5.45 fmj to cause more "stun" effects than a bullet which deals the same amount of permanent damage without the same temporary cavitation. Those sorts of details would be nice to have, but not as important as the points in my earlier posts.

Well, if you think about it with the new gear system and the accountancy for 'armor' then this would be nullified. I don't know how that would work. Chance of penetration?

Yeah, armor is sort of a whole other can of worms. Low level armor doesn't stop rifle rounds - in some cases it may affect how the bullet does or does not tumble or fragment, but in others it may not. These days ammo companies design their bullets to be "barrier blind" and shooting gel through barriers like glass, wood, cinder block, and steel sheets frequently produces the same sorts of wounds as without any barrier.

For higher level armor, we know its guaranteed to stop certain numbers of rounds from certain ammunition, but we have little info on how many rounds of other ammunition it will withstand, or what happens when the "guaranteed hit number" is exceeded. For example, if a trauma plate is guaranteed to stop three hits of 7.62 NATO AP, what happens on the 4th hit? It may be destroyed on the 3rd hit and immediately start letting rounds though as if it wasn't there, or it may let rounds through with reduced wounding ability, or it may stop a certain number of other rounds - this info generally isn't given out. Moreover, we typically aren't told specifically how many rounds it will stop of 5.56 fmj, 5.56 AP, 7.62x39, or other miscelaneous mil-spec loads.

Higher level armor is also allegedly more vulnerable to pistol caliber rounds than to rifle rounds, since it is prioritized to stop the latter. But without buying a bunch of armor and shooting it first hand, I don't know that you could realistically answer all these questions, even though it is important in creating an accurate simulator.

I agree. It's stated in many LE wound ballistic articles that a number of those shot in a firefight actually bleed out elsewhere other than the position they got shot from. They normally get to cover and away from the area before bleeding out, going unconscious and so on. Weighing non versus lethal is all about hit detection and how the damage values are utilize though.

A refined bleeding system could definitely go a long way to making wound ballistics in games more realistic. In Red Orchestra 2, many shots that don't kill you outright bleed you instead, about half of which you can bandage if you react fast enough. In many cases, it works out pretty nicely - a lot of the time, you shoot someone and even if it doesn't kill them outright, they just crawl into a hole and try to bandage themselves, so it still effectively stops them from whatever they were trying to do when you shot them. They might eventually come back, but many times they still don't manage to bandage themselves in time, or since they're stuck in a ditch in no man's land, they'll just get shot again as soon as they poke their head out. Other times, a particularly determined player might choose to shoot you back rather than worry about themselves. There are also many times where a wounded player bleeds out in only a few seconds, and their screen is too dimmed to do anything, but it does tie up your attention for longer than if they just dropped instantly. The variation and uncertainty is pretty good.

Of course there are things to be worked on - pistol rounds in particular in RO2 are too easily shrugged off. Basically anything that's not a headshot can be bandaged in 3 seconds and then you go on like nothing ever happened. There's room for improvement and things to watch out for in these sorts of models.

I agree randomization and chance is always good to have, we're including it in CMS but it depends what kind of values you're looking at for what kind of factor.

Yeah, I mean you don't want things to be too random, and the more results that can be based on actual cause and effect, the better. But when X bullet pretty much always kills in 2 hits, while Y bullet always kills in 3 hits, things are getting too arcade.

[rye1 21]

These days ammo companies design their bullets to be "barrier blind" and shooting gel through barriers like glass, wood, cinder block, and steel sheets frequently produces the same sorts of wounds as without any barrier.

Some are 'better'. But that's mainly in HP/JHP where their 'petals' open out causing a very painful wound profile when it penetrates a barrier then meets flesh.

I don't know about any MIL-spec in that argument but it would be suggestive that the lowered velocity would allow for certain events like tumbling instead of creating a through-and-through.

There's some, limited, study on armour here:

http://m4carbine.net/forumdisplay.php?f=91

It's not a lot but it gives you some basis if it were to be applied in-game.

[lugiahua 26]

Higher level armor is also allegedly more vulnerable to pistol caliber rounds than to rifle rounds, since it is prioritized to stop the latter. But without buying a bunch of armor and shooting it first hand, I don't know that you could realistically answer all these questions, even though it is important in creating an accurate simulator.

Unless you are wearing only a plate carrier instead of full body armor system, there should be a LV-3A panel between you and the plate, which would stop most non-ap pistol rounds and fragments even the plate was penetrated.

[Lauxman 10]

Unless you are wearing only a plate carrier instead of full body armor system, there should be a LV-3A panel between you and the plate, which would stop most non-ap pistol rounds and fragments even the plate was penetrated.

Well, most infantry types highly prefer plate carriers over IOTVs, soooo...

[scrim 1]

Plate carriers also have Kevlar panels. The difference between a flak vest and a plate carrier is that the latter only has Kevlar behind the trauma plates, whereas the Kevlar on the flak vest stretches beyond what is covered by the plates, in order to provide more protection against low velocity rounds and shrapnel. Apart from that, trauma plates can easily stop pistol rounds, so that sounds a bit like a myth. That, and pistol AP rounds are designed to penetrate Kevlar. I highly doubt that anyone who thought of them had in mind for them to penetrate trauma plates that can withstand several AK rounds before breaking enough to let rounds through.