Realistic offsets

[Tiffy]

Recommended books on ballistics:-

Understanding Firearm Ballistics
Robert A. Rinker
Mulberry House Publishing
ISBN: 0-9645598-4-6

American book concentrating on smallarms ballistics. Starts with very basic principles and builds to quite complex propositions and equations. Something for everyone with an interest in the subject in here.


Military Ballistics
Moss, Leeming & Farrar
Brassey's Land Warfare
ISBN: 1-85753-084-5


Concentrats more on ordanance but again covers the subject quite well. A bit more of a read that the previous book though.

 

[OICW]

{sarcasmBOTon}



ok, allow me to retort, NO most people who arent hardcore concerning doctrine HAVE NOT read the Geneva and Hague conventions, when i was in the Us Navy, we were HIGHLY discouraged as well as the USMC, in using our M2's against human targets, it was made clear to us, that ONLY when fired upon were you to engage infantry with the 50, unless it was your only recourse. So please take your :rollseyes: face and shove it where it belongs.



Also, i said ROUNDS, not bullets you tart, cannons as well as rifles, pistols, and hell, even bows and catapults fire, guess what? PROJECTILES, i was generally speaking. And last time i checked, any main gun IS NOT rifled on the few tanks i came into contact with....so please correct where its needed instead of trying to sound superiorly intelligent, when GUESS WHAT? You're not....:rollseyes:

Since we are correcting things, the correct term happens to be ROTATION or RATE OF ROTATION

Pretty sure that one is a new word for most English speakers too, possibly im just MORE DENSE, or have GREATER DENSITY than you


[rant]Now, lastly, id like to apologise for my technical terminology not being up to par with the rest of your giant phucking brains, and also, my ranting sarcasm, i get tired of people correcting what they surmise to be incorrect based on simple misunderstanding of plain terminology, YES, i could reread my tech manuals and directly quote them on these boards, i'd rather try to explain things in simpler terms for those not 'in the know', but apparently everyone here seems to think they are either so much smarter than everyone else based on thier regurgitated, bland posting of something someone else wrote, or are so detached from thier human interaction skills that they forget, that although someone may be wrong, it doesnt necesarrily mean they are stupid or ill informed, they may only be dumbing themselves down for the benefit of the younger or less tech geeky people who read this BS. Please pardon me for having the slightest personality and consideration for others feelings....[/endrant]

and i think ill overuse this emoticon yet again

and once more for good measure so i can imply that my uberintelligencia field patch has been earned {sarcasmBOToff}


just funnin guys, do you really realize how irritating it can be to have someone attempt to make you look stupid by picking apart every lil word you type?

I'llk wander back into the Dev forums, and remember that most of the decent people are helpful and not looking for an E-penis pissing contest now thank you

PS Tiffy, still waiting for that info on your spiffy english weapon in my PM box

Learn to type and take some comprehension lessons

I only pick apart people who say stupid things, and coming from me, that should inform you how stupid you've been.

I lack interaction skills? Is that because I know how to construct sentences and make a reasonable use of grammar now?

Anyway, your mention of "hydrostatic" shock proves again how little you know about wound ballistics. Next you'll tell me that being scratched by a bullet is instantly fatal.

Bullets create 2 things when they hit flesh. A temporary cavity and a permanent cavity. The temporary is the, surprise surprise, temporary inflation of tissue caused by the energy of the round. It does no damage whatsoever to blood vessels and muscle, because they are flexible

On the other hand, the temporary cavity can rupture fluid filled organs, mainly the brain and liver.

The permanent cavity is the physical hole created by the bullet. That's how bullets do damage, period. Hydrostatic shock is complete and utter BS. There is no all powerful shockwave from a bullet that instantly kills people. Do you realise how much force would be required to force blood the wrong way through arteries and veins? A f*cking lot more than what a bullet can do.

www.tacticalforums.com

Go to the Terminal Effects forum and post about hydrostatic shock there. You'll be utterly destroyed by people who have made wound ballistics their business for the past few decades.

 

[-Freshmeat]

Thanks for the references. Will go reading before opening my mouth on the subject again

-Freshmeat

 

[Tiffy]

I'm backing OICW up on the hydrostatic shock thing. It'll burst barrels full of water nicely but doesn't make much of an impresion on a flexible target.

Having read my earlier post I can beleive I said what I did. A rounds wounding potential is reduced as it slows to a sub-sonic speed due to redued energy and the destabalising effects of passing through the transonic zone. This instability induces the bullet to slow at a far greater rate. The size of the temporary and perminant cavities are reduced due to the lower energy level of the round.

Having said all this you ain't going to see any of this in INF with most of the weapons as their rounds are very supersonic out to ranges greater than most people can hit a man sized target at.

< must make an effort to not post when tired or in a rush >

 

[Gnam]

Viet Nam era: Sgt. Carlos Hathcock scored a one shot one kill with an M2hb fitted with a 10X UNERTL scope, @ over 1000 yards, the target simply disappeared from the waist up in a nice bloody spray...

WOAH!!! HOLY ****!!!

 

[Lasersailor184]

Just a FYI, anything larger then .50 is forbidden to use on infantry.

Although if the **** hits the fan, you're going to use whatever you have available.

 

[Beppo]

just one thing (haven't found an answer to this yet):
At what distance of ie the M16 projectile would the damage taken actually decrease in a way you would notice?

There are some games and mods out there that use a very simple rule of damage/distance but they end up extremely unrealistic. I don't think that firing on a soldier that is 100m away from you would need ie 6 rounds to actually kill and on 50m only 3... looks a 'bit' off for me tho.
So if a future INF version should model this realistically then we need an answer to my above question. At what distance this all starts to really modify the rounds damage potential?

 

[OICW]

For the M855 round, it stops fragmenting below 2500fps. Between 2500 and 2700fps, it fragments into (usually) two pieces, and above 2700fps, it fragments into many fragments

When it doesn't fragment, the wound isn't very great as it doesn't yaw as greatly as other non-fragmenting rifle rounds.

Stolen from the Ammo Oracle (www.ammo-oracle.com) are these figures:

75° F, 25% humidity, at sea level

Distance to 2700 fps
20" Barrel
16" Barrel
14.5" Barrel
11.5" Barrel

M193
190-200m
140-150m
95-100m
40-45m

M855
140-150m
90-95m
45-50m
12-15m

 

[Spier]

Just a FYI, anything larger then .50 is forbidden to use on infantry.

Although if the **** hits the fan, you're going to use whatever you have available.

All I have found on that is that it is "forbidden" to use bullets that weigh under 400 grams with explosive fillings and such(St. Petersburg declaration). Have you read up on it, or is it just some rumour you have heard?

When it doesn't fragment, the wound isn't very great as it doesn't yaw as greatly as other non-fragmenting rifle rounds.

Really? I was under the impression that it did yaw quite a bit more than the M193. Got some sources?

 

[OICW]

www.ammo-oracle.com

http://home.snafu.de/l.moeller/military_bullet_wound_patterns.html

 

[Spier]

www.ammo-oracle.com

http://home.snafu.de/l.moeller/military_bullet_wound_patterns.html

I didn't read through all of ammo-oracle, but IIRC, it is based on "Military rifle bullet wound patterns by Martin L. Fackler", right? Anyway, the pictures in the last one just confirmed what I said: the m855 seems to start yawing at around the same point as the 5.45x39.5mm, earlier than the 7.62x39, earlier than the 7.62x51 and earlier than the M193. Unless you meant something else when you said "yaw as greatly", then I don't see your point.

 

[Tiffy]

just one thing (haven't found an answer to this yet):
At what distance of ie the M16 projectile would the damage taken actually decrease in a way you would notice?

There are some games and mods out there that use a very simple rule of damage/distance but they end up extremely unrealistic. I don't think that firing on a soldier that is 100m away from you would need ie 6 rounds to actually kill and on 50m only 3... looks a 'bit' off for me tho.
So if a future INF version should model this realistically then we need an answer to my above question. At what distance this all starts to really modify the rounds damage potential?

The short answer is, a NATO helmet is penetrated with enough residual energy to incapacitate the target at 640m, Kevlar is penetrated at 750m and an unprotected man at 1200m. Thats using SS109 amunition and shooting from an M16A1.

The longer answer:-

"Historically it has been accepted that is a projectile dumps 80J of energy into a body very quickly, then that person is likely to be incapacitated."

This value has been in use for about 100y years so who am I to argue.

(Source Small arms:General design by Allsop & Toomey pub.Brassey's land warfare)

CRISAT Technology Area 2 (TA2) laid down definations of "Incapacitiated" and "Suppression". (Unfortunately most NATO countries use other methods of defining this and none are standard - so I'm using the British way).

"Incapacitation". This is when a person is unable to carry out their primary function. This is defined in the following table: -

Distance to Target (m)... Delay (s)... Duration of incapacity... Probability of achieving
0 to 100...................... <1........... 5-10 min..................... 90%
100-600...................... 4 desirable. 3 hours...................... 90% desirable
................................. 8 essential.................................. 75% essential

(source Annex 2 of TA2)


From this we can get to the short answer values (which I happened to lift from Small arms: General design ... why duplicate work).

As a side note 9x19mm Para ammo falls below the 80J mark at about 800m and never has enough energy to penetrate the standard NATO helmet, even at point blank range. A 7,62x51 NATO round on the other hand delivers considerably more than 80J out to well beyond 2000m. However to penetrate the standard NATO helmet and incapacitate the target (deliver the required 80J) that range drops to 620m which is less than for the SS109 round. It does fair better against body armour with a range of 900m though.

Hope this answers the question - and I didn't get into whether the bullet fragments, yaws, does handstands or just beats the target into submission with a mallet



PS: What clever sod is going to tell me how to bloody do tables in posts?

 

[Beppo]

Thanks for all this Tiffy, but do you have an idea on where to get 'real' charts that would allow to build up a system for projectiles within a game that then simulates the damaging realistically? The 'probability table' and the Joule examples do not really show me something that I would be able to transform into some sort of formula or similar. Ie. can a simple percentage be used that changes the damage capacity of a round starting with 100% that decreases the further the projectile travels? Would something like this be realistic at all?
I for one cannot really believe that a shot into my stomach taken from 100 or 400 meters ends up with me being 'differently wounded' in terms of real damage taken and being able to move on further ... be it in RL or for a game. I would think that no matter how far away the shooter was, that I would not be able to 'play' any further with such a wound in the middle of my stomach. Sure if the shooter was very far away then it maybe ends up with a smaller bleeding and not as many fragments and so the chance of surviving would be higher due to the smaller amount of blood vessels being disrupted for example. But I would end up being 'incapacitated' anyway...

So, would a system like in another mod where you need 20 rounds on 200 meters right in your upper body and only 5 rounds on 50 meters be realistic?? I would never believe this I guess...

[edit] to the tables... use the code tags... [/edit]

 

[yurch]

What I got from the first table seems to be that there's a 90% probablity that someone getting shot once in a distance shorter than 600 meters won't be doing anything effective.
The 80J mark seems to basically be the maximum effective range of the projectile where a single shot can deliver an incapacitation.

Either way with a gutshot at 100m or 400m, it seems quite likely the target will be going down. No 20 shots about it, these are for single hits.

 

[Tiffy]

A quick comment.... I'll make some more after work.

The % of incapacitation is a desired design level and takes into account the percentage of achieving a hit and once hit the percentage of actually incapacitating the target. If we assume the soldier always will hit the target the percentage chance of achieving an incapacitating hit reaches nearly 100%.

Remember a 5.56NATO round has enough energy to incapacitate the target all the way out to 1200m (just hasn't got a hope in hell of hitting him).

What I'm trying to show is that, unless we're talking about pistol round the wounding capacity won't change in the kind of ranges we're talking about in INF. Hell RtK looks to be about 500-600m from one hill side to the other (which means its probably all of 300m in UT units).

Post more later as I'm running flipping late.

 

[gal-z]

I think u have a little mistake - ss109 rounds fired with m16A1 won't go far beyond 25m, because they require 1:7" twist barrel rather than 1:12". My friend accidently fired an ss109 round with his m16A1 and let's say it didn't hit the target with it's tip. And it was pretty short range.
As for difference in damage, I'll try to find something, but I doubt anybody would know anything useful. Looks like using the m/s of the bullet for each range is a good start.

 

[Logan6]

Back on to the subject of bullet trajectory, I remember a long time ago seeing an excellent bullet trajectory table for different rounds. I believe it was on Remmington's web page ( Remmington Rifles ). I think there does need to be some tweaking done on the bullet drop and some on the precision of the weapons. Am still having problems with long strays on the shooting range even though I have brought my graphics up to 1280x1024 and am firing from a crouch for better support. Would be very nice to put some calibrated mil dots on the M16 ACOG scope. I looked it up on the Web and the sight picture shows 2 or 3 more mil dots on it than the one in game, out to 800 meters if I remember right.

 

[yurch]

The ballistics ARE based somewhat on any firing table information I could find.
They are for the most part 'accurate' to whatever scale and ballistic zero inf is using them at. The shooting range targets are MUCH larger than man-size, and it's not advisable to use them for a sense of drop scale in relevance to a human target.
Especially if you consider whatever 'error' the weapon model may be leading you to shoot at.

 

[jayhova]

I think that it is safe to assume that the bullets fired in INF are the non-fragmenting variety. The fragmenting bullets are (if I'm not mistaken) German. The vast majority of rounds fired are thick jacketed and hold together when they transition to a 90 degree state. The thing that causes the most damage is this transition.

Bullets are basically unstable because they have the center of mass well back from the tip. Since it is the mass that provides the inertia to keep the bullet moving forward and air resistance is pushing back on the tip the bullets natural inclination is to weathercock around so that it's center of mass is forward. Gyroscopic stabilization works against this keeping the bullet pointed in the same direction. At the same time small imperfections in the bullet will alter it's flight path through the air into a corkscrew pattern. Think of this like an unbalanced loan in the washing machine. In addition to these factors as the bullet travels it's flight path becomes less in line with the direction the bullet is pointing. The reason this is, is the bullet is being pulled towards the ground faster by gravity but the bullet is still pointed in the same direction it was when it was fired. This is how gyro stabilized projectiles like bullets differ from fin stabilized projectiles like those fired from a tank. All of these factors will act on the bullet when the target is struck causing it to turn 180 degrees so that the tip is pointed in the direction of the entry hole. It is this transition that causes the most damage. Because the bullet is traveling sideways at this point it opens up the biggest cavity and causes the most tissue damage.

Ok, here is where things get interesting. The damage a target receives from a bullet can actually be less when at close range. The reason for this is That the bullet is moving faster and is more stable. It's flight path is also almost directly in line with the direction it is pointed. Think of this like balancing the end of a broom on your palm. As long as the broom is orientated straight up and down it is quite easy to keep upright, but as it leans more to one side it will fall faster and will take more effort to keep straight. The upshot of this is that at close ranges the bullet takes approximately 8"-10" of travel before it transitions and can actually penetrate through the target before it flips around. At medium ranges the bullet has less tendency to over penetrate. At far range there is a diminished chance that the round will penetrate amour with enough force that the bullet can penetrate the target and rotate 180 degrees. Of course in addition to all of these factors is the speed of the bullet and it's ability to disrupt tissue which drops as it loses speed.

 

[keihaswarrior]

jayhova, the 5.56 ammo in INF should be fragmenting quite a bit.
Take a look at this nice table:
*--Up to about 100m, the bullet completely fragments tearing a large permanent cavity inside the target.
*--Between 100m and 200m, the bullet doesn't fragment much other than breaking into two parts at the cannelure.
*--After 200m, the wounding potential drastically decreases because the bullet is cleanly entering and exiting the target. It still yaws, but the largest cause of bleeding (fragmentation) no longer happens.