# Bullet Damage Formula?



## Cryotech (May 25, 2011)

Hello, new here and nice to meet you all 

I realize this is a handgun forum, but I was hoping someone here would know what I'm talking about since you're the experts in this particular field.

I develop games and am currently in the process of developing two games that require the calculation of bullet damage but I'm not sure how to properly do this based on the ballistics type of firearm used (pistol, rifle, shotgun etc.) to ensure it's realistic in-game. I've tried searching for this information online but was unable to find what I needed. Too be honest, I'm not exactly sure what I should be looking for formula wise.

If anyone here could help me, I would be extremely grateful for the help!


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## buckler (May 24, 2011)

nobody has the answer that you seek, sorry. If anyone did, about 90% of the defensive handgun and ammo market would quickly disappear, because so much of it is based upon nothing more than "hype".


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## MLB (Oct 4, 2006)

Complicated stuff in real life. For a gaming scenario, I'd think that muzzle energy would be a good place to start to reasonably scale one projectile to another. You can find this info at any of the manufacturer's websites.


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## buckler (May 24, 2011)

*General Hatcher had a formula in his "Notebook", but it was based upon lies*

that LaGuarde put out about his and Thompson's "test" on a lousy 6 steers back in 1909, or thereabouts, which proved exactly nothing. The entire test was published in the 1981, or 82, I forget, Gun Digest, and it was a complete joke. So what the "computer man" RII test of the 1970's. Garbage in and garbage out, as they say. flawed testing means, and or flawed presumptions/protocols naturally lead to bs results. If .45 military "ball" fmj (full metal jacket) ammo was anywhere close to being as "effective" as all the war stories would have us believe, an alley cat couldn't run off with one thru his chest, but they do, routinely, you can prove it for yourself. Ditto *****, chucks, jackrabbits, nutria, armadillos, opposums, many vermin type critters that you can easily hit with a handgun, if you try. But nobody wants to go to that much trouble, it seems. I am certain that the reason that they don't do so is they don't want to know the truth. Low velocity, heavy for the caliber jhp's don't expand much, or reliably, in flesh. It is that simple. You need at least 1000 fps in a .45, and 1200 fps in 9mm.


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## Cryotech (May 25, 2011)

Thanks for the replies,

@Buckler - I understand what you're getting at but 'purely accurate results' isn't what I'm looking for. Though if those did exist, I would be one happy camper lol. What I'm looking for is the generalized formulas used in ballistic testing, which I do know exist because I've seen them, but I just don't know where to find them. If they didn't exist, we game developers would have nothing to go on to make the damage as realistic as possible in-game. I realize there's many factors and variables and I will never truly accomplish a true-to-life conversion, I just want to achieve as realistic statistical damage as possible which will require tweaking on the backend to accomplish the actual physics of it engine wise. That's why all I really need is just a basic formula that is 'generally' used to calculate ballistic damage.

You're statement about 1000 fps in a .45 and 1200 fps in 9mm is heading down that right direction. What is the formula you use to figure this out when trying to calculate bullet damage?

@MLB - Thanks for the info, I found some information regarding muzzle energy but I'm at a loss on how it factors into the equation. I've tried experimenting, but can't figure it out. I'll keep searching until I find an actual formula regards of how generalized it is.


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## buckler (May 24, 2011)

some baloney claiming to do what you say probably do exist, but in reality, there is no way to know. Many men have continued to fight or flee after being hit with very powerful (momentum or energy) large caliber loads, so while you might up the odds of getting a stop with a powerful load, it's nothing like a formulaic thing. It's mostlly a luck thing, especiallly with loads less powerful than the famed 125 gr, full power jhp 357, from a 4" or longer barrel. The .44 mag has failed to stop men, the 12 ga slug and buckshot has failed to stop men, with close range chest hits. 3006, 7.7 Jap, and 8x57 and 7x57 ball failed to stop many men. Because so many millions of men were shot with such loads a 5% failure rate is still many 10's of thousands of men who were not stopped. Sure, they died later, but they did not drop to the shot, as so many of the ignorant are convinced always happens with such rifle loads.


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## Cryotech (May 25, 2011)

@buckler - True, there is no "absolute" way to know and this I realize, but there _is_ generalized formulas used to calculate the _potential_ damage a gun could cause. These numbers are then pumped into the game engine and the physics are tweak to attempt to obtain a more realistic feel.

Of course some people drop where they stand or flee or fight, and it all depends on the type of gun used, bullet used, shot location and yes, luck. But that's not what I'm looking for because I don't care about that aspect of the formula. I can convert that by adding my own specs. Again, what I want is a _number_ I can work with.

What I'm looking for or asking if anyone knows about, is any formula that ballistic testers use to calculate the potential regardless if it's baloney or not. That's what I'm looking for and I know those exist.


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## MLB (Oct 4, 2006)

Hello Cryotech. The muzzle energy is the product of the velocity (at the muzzle) and the bullet mass.


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## Steve M1911A1 (Feb 6, 2008)

Oh boy! *Buckler* has certainly put his foot into it now! He's set himself up to say that Hatcher, and Thompson and LaGarde, were peddling bull dung. How very interesting!

Tell me, Buckler, just how many animals have you killed and dissected, to arrive at your conclusions?
Exactly none. I'm certain of it.

Instead of reading a "digest" of what they wrote, have you ever read their original work?
No, I didn't think so.

I strongly suggest that you stop giving advice on subjects about which you so very obviously know nothing.
Either do some real experimental work, or, at least, read the original writings you wish to condemn.
Then gain some real shooting experience.
Only then should you seek to advise the rest of us.


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## Steve M1911A1 (Feb 6, 2008)

*MLB* has set you on the right track, *Cryotech*.

Along with muzzle energy, you might wish to figure-in terminal energy at the distance at which a given hit was made. These figures are available from ammunition-manufacturers' web sites, usually as muzzle- and distance-related tables. Particularly useful might be Remington, Winchester, Hornady, and Norma. Also look up the ammunition tables in the Gun Digest, if they're available on-line.

The concept is further complicated by the construction of the particular bullet. Some bullets do not appreciably expand, and some expand to much more than double the original diameter. Some almost explode within flesh or other semi-fluids.

So each calculation of "bullet damage" could conceivably include bullet velocity at the moment of contact, original bullet diameter, expanded bullet diameter, and bullet mass.

Did that help?


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## DanP_from_AZ (May 8, 2009)

Cryotech said:


> I develop games and am currently in the process of developing two games that require the calculation of bullet damage but I'm not sure how to properly do this based on the ballistics type of firearm used (pistol, rifle, shotgun etc.) to ensure it's realistic in-game.


Yep, the guys are correct. You have stepped squarely into a old and continous and bitterly fought controversy on how to evaluate calibers and ammo "stopping power".
_*"Big and slow (say .45 ACP) or "Small and fast (say 9mm +P).*_
This will go on forever. It can't be done "correctly". WAY too many variables.

But, you want a simple algorithm to plug numbers in to "separate" weapon lethality. 
No problem. If you don't need to make it match the real world.

Here is a long table of Dexter's Table of Hatcher's "work". Done in the '30's. Yes, it's rather old. And, discredited.
Hatcher's formula is discredited. Dexter's table of results is fairly current, and calculates Hatcher's formula correctly.

At the top is how Hatcher calculated the data for various calibers and stuff. And then a long table of
calculated "data". Here is the "header" at the top of Dexter's Table of Hatcher values.

_The Hatcher Formula is an attempt to mathematically evaluate the approximate effectiveness of pistol ammunition at incapacitating a person.
Developed by Gen. Julian Hatcher in the 1930's, it uses the bullet momentum, frontal area, velocity, and a 'form factor.'
The formula is: 
*RSP = M * A * F*
where RSP = Relative Stopping Power Index, M = Momentum of the bullet in foot pounds, A = Area of the bullet in square inches, 
F = Form factor derived from his observations with some additions for later bullet types. The table lists an RSP for each 'Form Factor',
whether or not that form of bullet actually exists for a particular caliber or weight. The form factors presented below include:_ 
_0.70 Fully Jacketed Pointed
0.90 Fully Jacketed Round Nose
1.05 Fully Jacketed Flat Point 
1.10 Fully Jacketed Flat Point (Large flat)_
Hatcher's Theory Of Relative Stopping Power

If you've made it this far, I'll go you one better. Here is a "Hatcher data calculator" which allows the input raw data
(which you can get from the Dexter Table) and takes care of all the conversion factors necessary to to get the output in proper units.
Stopping Power Calculator

From these two items, you can reverse engineer your algorithm, needing only a "few" look-up tables.

This takes care of "handguns". For "larger" weapons, just get input data for rifles and shotguns.
A good source is the ammo section of Midway USA. Just select a few "representative" rifle and shotgun "loads".
Ammunition - Shop Premium & Discount Ammunition at MidwayUSA

All this is almost completely bogus in terms of predicted performance in the real world.

But, not to worry. You are after a "mildly logical algorithm" which has a shot (pun intended)
at separating "weapon performance" on some human or alien or whatever.

You have enough "meat" here to at least start that job, I think. Good Luck ! :smt1099

Oh yeah, plain old physics.
Momentum MV= Mass (M) x Velocity (V)
Area A = Pi x Diameter (D) x Diameter (D) that is, D squared. Pi =22/7. For us, 3.14159265 is close enough.

Kinetic Energy KE = Mass (M) x Velocity (V) x Velocity (V) that is, Velocity Squared.
KE is often used as a crude indicator of a cartridge's "go-power". 
Both Velocity and KE are listed for ammo in Midway USA's ammo section.


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## DanP_from_AZ (May 8, 2009)

MLB said:


> Hello Cryotech. The muzzle energy is the product of the velocity (at the muzzle) and the bullet mass.


Not to get too technical here, but long ago Sir Isaac Newton established "how the apple falls". :mrgreen:

Momentum MV = Mass M x Velocity V.
Kinetic Energy KE = Mass M x (Velocity V) x (Velocity V). That is, V squared.

When fooling with this stuff for ammo, Mass M is in grains. Velocity V is in feet/second.
Getting KE in foot-pounds requires figuring out a nasty conversion factor.
I will leave *THAT *to the student. :smt1099


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## Steve M1911A1 (Feb 6, 2008)

It's always nice to hear from someone who knows what he's writing about!

Thanks, Dan.

(I wonder if maybe we should PM Cryotech with all of this stuff.)


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## kg333 (May 19, 2008)

Steve M1911A1 said:


> It's always nice to hear from someone who knows what he's writing about!
> 
> Thanks, Dan.
> 
> (I wonder if maybe we should PM Cryotech with all of this stuff.)


After that disgrace of a sequel, I doubt Crytek is looking for realism. Send it to these guys: Bohemia Interactive

:smt179

KG


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## Steve M1911A1 (Feb 6, 2008)

Huh?


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## kg333 (May 19, 2008)

Nevermind, thought you were making a crack about Crytek. Didn't notice the OP's name...'twould appear to be a rather uncreative moniker.

KG


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## DanP_from_AZ (May 8, 2009)

Steve M1911A1 said:


> It's always nice to hear from someone who knows what he's writing about!. . .


Thanks Steve, a warm fuzzy is ALWAYS appreciated.

Long ago and far away I worked 31 years in automobile passenger car safety. In a lot of different areas.

My most favorite cartoon EVER was from around 1970. It shows two guys standing in front of a room-sized computer.
One says "the world is full of data, much of it yearning to be analyzed". It became my motto and mantra.tumbleweed


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## MLB (Oct 4, 2006)

Dan, thank you for the correction on energy vs momentum. I did indeed neglect the V^2. Always happy to see a critical set of eyes on the boards.


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## ozzy (Apr 16, 2011)

Cyrotech I would help you out but I'm not that savvy, I hope you can find the answer here that your looking for.


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## DanP_from_AZ (May 8, 2009)

MLB said:


> Dan, thank you for the correction on energy vs momentum. I did indeed neglect the V^2. Always happy to see a critical set of eyes on the boards.


Thanks. And thanks for reminding me about " X^2 ". Sure saves keystrokes.

I'm old enough to no longer worry about my memory lapses. They're too frequent for that. :mrgreen:


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## Cryotech (May 25, 2011)

Wow! Awesome advice all! And very much appreciated!

Too be honest, I didn't know what I should be looking for and though I knew, just through commonsense, that velocity would have to play some major part in the overall damage, I didn't quite understand how it all tied together. 

@MLB - Awesome, thanks for the additional tip. I was actually working on my physics formula for bullet damage until I received the much appreciated PM updates from Steve and Dan. You all definitely made my life a heckalot easier lol.

@Steve - Never even thought of that, nor even knew those tables existed, which would explain why I never even thought of it lol. Thank you, it did help.  I did some searching on the top manufacturer sites but was bombarded by a plethoria of information that basically blew my brains (no pun intended lol). I do average everyday physics, even quantum physics and I can program 5 different computer languages but I have to admit, the knowledge you all know is waaaaay over my head lol so my hats off to all of you. You're truly professionals of the field. I was completely lost trying to understand all the different grains, bullet shape and type, barrel lengths and a lot more I'm still trying to digest that adds just another variable to the mix of 1,000,000 other variables lol. I think that's where I went wrong. I was trying to substitute commonsense physics by making it way to complex with all the variables of a firearm's bullet. But, that's extremely hard not to do because every little bit adds to or takes away from the overall damage capabilities of the bullet itself. 

@Dan - *whistles* That's exactly what I was looking for  In game wise, there'll be additional factors of course and will require some tweaking for physics, but that's the easy part lol. Thanks a million! Combined with that data and the tables Steve pointed me to I'm going to be going nuts with firearm conversions lol. 

@kg333 - Thanks for the link, that game looks wicked sweet!

Again, thanks for all the help everyone, I'm truly grateful for such wonderful advice!


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## buckler (May 24, 2011)

hatcher was full of it, he based most of his "formula" on LaGuarde's LIES about the "test' that he and Thompson did on a lousy 6 steers, back in 1907 or some such, with ridiculously out of date rds. 476 Eley, 38 long Colt, 455 Webley, stuff nobody knew or cared about by the 60's, much less today. The test proved nothing, because it was so egregiously out of spec in the first place. All 6 steers were still standing after 2 full minutes after taking 6 rds in the chest. the cadavers, hung by the neckl, "twitched a bit', when shot thru the chest with handgun rds, but no measurements were even attempted. the entire test result was published in the Gun Digest, `1981-82, I forget which. It's also been published, look for it at Ray Riling Arms Books, or used at amazon.com or in your library's BOOKS IN PRINT reference works. Read it for yoursel, and LAUGH at Cooper, Hatcher, Taylor and the rest of the 'momentum' bsing crowd.


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## buckler (May 24, 2011)

such a table, etc as you seek would require consistant hits on the same organ, at the same angle, same depth of penetration, etc, totally bogus assumption, basically.


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## Steve M1911A1 (Feb 6, 2008)

*buckler*, go away and grow up.


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## ozzy (Apr 16, 2011)

buckler said:


> such a table, etc as you seek would require consistant hits on the same organ, at the same angle, same depth of penetration, etc, totally bogus assumption, basically.


And the Professor again S.O.H.A. :numbchuck:


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## buckler (May 24, 2011)

you can't challenge what I say in any logical manner, so you have no choice but to resort to general degradation sorts of comments. It is a very revealing "tactic" of those who lack any real "ammo" in a debate.


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## Steve M1911A1 (Feb 6, 2008)

OK. That's it. I refuse to waste time arguing with an idiot.

*buckler*, you can post whatever you like from now on, and I won't engage you.
Of course, I may also post in the same thread, and write something that actually makes much better sense.
But I won't argue with you.

You are a troll and a fool. But someday you may grow up.


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## Cryotech (May 25, 2011)

@buckler - As much as I appreciate your advice and you trying to help, I have to admit that you haven't added anything to the conversation that is remotely useful to me in any form. To be honest, I don't really care about "personal insight" of what is truth or what isn't, because I know for a fact ballistics can be performed and with high degrees of accuracy. An example would be Forensic Scientists using ballistic testing and accurately pin-pointing the type of firearm, bullet as well as the grain by using ballistic calculations based on the damage caused. Maybe this information stems from Thatcher and maybe it doesn't but to say that what they do is a "lie and is bogus and cannot be done" doesn't make sense, is bogus in-itself, shows you haven't done your research enough to commit supporting facts to your argument and doesn't help you in your debate and would never stand up in court, literally.

I personally wouldn't say what they did was a "lie" but more of a viable test with as accurate information as possible based on what they had to work with at the time. Of course nothing is ever going to be 100% accurate there is just way to many factors negating true accuracy. Even today's ballistic testing methods are not 100% accurate but they are pretty darn close enough to be considered accurate enough for forensic evidence in court and that's good enough for me.



> such a table, etc as you seek would require consistant hits on the same organ, at the same angle, same depth of penetration, etc, totally bogus assumption, basically.


Your argument noted above doesn't make sense. Even if you shot someone with an extremely high-powered rifle at point blank range with a FMJ and if they miraculously lived, and you shot them _exactly_ in the same spot, with the same angle of entry and same depth of penetration, at the _exact_ same distance etc, sure you might kill them and you might not, but chances of you actually pulling all that off perfectly are higher than you winning the lottery based on all the minute variables and _no_ test based on those statistics would _ever_ be considered accurate because it's unrealistic because the secondary bullet wouldn't have any initial resistance as the first bullet did and therefore would do more damage beyond the first bullet thus throwing off your purely accurate statistics. _That_ is a true bogus test.

I really don't understand why you're taking this personal and getting all up-in-arms (pun intended) about a topic you obviously have no interest contributing useful information in. the funniest thing about your whole debate, in my humble opinion, is the fact that your arguing on a thread that was posted to gain some sort of "generalized" (hint, generalized means just that. It doesn't stand for pure, realistic accuracy based on bogus information you claim doesn't exist, which in-itself doesn't make sense because it has to exist for you to claim it's bogus to begin with) formula to be used in a GAME engine. Truth of the matter is, it's not how many times someone or something was shot in the same exact place that matters to me, it's the OVERALL damage done to the body that causes it to cease it's digital life that matters. Not sure why you can't understand this.

If it were me, I'd seriously think about the maturity of it all and how it reflected and made me look to everyone else. But, then again, that's just me.


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## Cryotech (May 25, 2011)

To everyone else, thank you for the information that did help


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## kg333 (May 19, 2008)

Handled with grace, Cryotech, and my apologies about my jab at your name. Best of luck with your game, and let me know if you need beta testers! :mrgreen:

KG


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## DanP_from_AZ (May 8, 2009)

Cryotech said:


> @buckler - As much as I appreciate your advice and you trying to help, I have to admit that you haven't added anything to the conversation that is remotely useful to me in any form. . .


I got the "idea" about Buckler when Steve pointed out some other threads in which he posted which I took the time to "review".
With that, Buckler no longer "counts" with me.

Cryotech: If there is anything that I can possibly contribute to your project, feel free to PM me. Or maybe you could start another "Post request".
As I'm sure you've figured out, I am a data and algorithm "junkie".

Long ago and far away I devoted my life "playing with our real world car accident data". The stakes were VERY high.
And I came up with conclusions that kicked the sxxt out of university and NGOs' conclusions based totally on their personal bias.
It did result in them attacking me on a personal basis. But, they couldn't refute the "real stuff".
Now that is GREAT fun !

As a private pilot and a beta tester, I had also had low-level fun as Sierra bought "Fly !" and tried to create "Fly !!".
And then they gave up and threw the FLY !developers under the bus. Microsoft's Flight Simulator was just too much competition. 
Trying to create the "stuff" that makes a computer simulation "feel real" to a real pilot is quite a challenge.

But, most of all, I REALLY want to know who hijacked Buckler's atavar. Come on, 'fess up to your "good work". We are having bigtime fun now ! :smt1099

OK, I just read this again. Forget all that stuff. I'm 68. I've been retired 14 years.
It is definitely time to get back to golfing, 4-wheeling, target shooting, and mountain hiking with my dogs. :mrgreen:


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## Steve M1911A1 (Feb 6, 2008)

*buckler* was caught in an outright lie about his shooting experience, which I reported to the Moderators.
That's why he was closed-down.


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## DanP_from_AZ (May 8, 2009)

:smt041


Steve M1911A1 said:


> *buckler* was caught in an outright lie about his shooting experience, which I reported to the Moderators.
> That's why he was closed-down.


OK Steve, I can certainly buy that. Sure makes sense about "Buckler" and his personal problems and his comments to posts.
I still really, REALLY want to know who hijacked his avatar. Come on, "someone" needs to 'fess up.:nutkick:


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## VAMarine (Dec 25, 2008)

DanP_from_AZ said:


> I still really, REALLY want to know who hijacked his avatar. Come on, "someone" needs to 'fess up.:nutkick:


I am SHOCKED that you would think someone here would hi-jack an avatar, SHOCKED!!!!!

As to "Buckler" just google "Gunkid" this clown just got out of prison and is one of the internet's biggest trolls/frauds.


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## VAMarine (Dec 25, 2008)

As for bullet damage, I've found these to be valuable research tools.

LE - Wound Ballistic Videos

LE - Wound Ballistics


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## DanP_from_AZ (May 8, 2009)

VAMarine said:


> I am SHOCKED that you would think someone here would hi-jack an avatar, SHOCKED!!!!!


OK, "ferris bueller, BUELLER" ???
Or, alternately, the Captain Louis Renault Award.
"http://www.youtube.com/watch?v=T1DEG6BWgp0"

'Common, somewhere there is a turkey in the background who is going to 'fess up.
So, "VA" you HAVE to follow your creed. 'fess up"

*"This is my rifle. There are many like it, but this one is mine.

My rifle is my best friend. It is my life. I must master it as I must master my life.

My rifle, without me, is useless. Without my rifle, I am useless. I must fire my rifle true. I must shoot straighter than my enemy who is trying to kill me. I must shoot him before he shoots me. I WILL...

My rifle and myself know that what counts in this war is not the rounds we fire, the noise of our burst, nor the smoke we make. We know that it is the hits that count. WE WILL HIT...

My rifle is human, even as I, because it is my life. Thus, I will learn it as a brother. I will learn its weaknesses, its strength, its parts, its accessories, its sights and its barrel. I will ever guard it against the ravages of weather and damage as I will ever guard my legs, my arms, my eyes and my heart against damage. I will keep my rifle clean and ready. We will become part of each other. WE WILL...

Before God, I swear this creed. My rifle and myself are the defenders of my country. We are the masters of our enemy. WE ARE THE SAVIORS OF MY LIFE.

So be it, until victory is America's and there is no enemy, but peace."*

OK, that's it, 'fess up. VAMarine. 'fess up. I have your six covered. :smt1099


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