Realistic offsets

[gal-z]

I think it would be nice if we'd have realistic bullet ballistics. Example for an M4A1 with SS109 ammunition would be:
25m -4cm
100m +7cm
200m +10cm
250m 0
300m -20cm
dunno the offset for 400 and 500m, since u r simply supposed to use a different cross on the trijicon for that... I assume it should be around -53cm for 400 and -133cm for 500m, though my calculation may be wrong. I used the fact that the distance between each 2 crosses is supposed to be 20cm at 300m, since u can shoot at 300m using the second cross on the trijicon.
There's a program called "remington shoot!" that u can download at:
http://www.remington.com/NR/exeres/...E1A991A136}&NRQUERYTERMINATOR=1&cookie_test=1
I just redownloaded it and gonna play with it a little

 

[Crowze]

Inf already has realistic ballistics.

 

[Derelan]

*collapse* *collapse* *collapse*

 

[gal-z]

I played around the shooting range and it doesn't look perfect to me, though I could be wrong.

 

[Grim_Reaper ~UFS~]

You want any better ballistics, you better have a terahertz computer.

 

[Derelan]

technically since INF's ballistics are not determined by any variables other than distance, not alot can be done to them other than changing the rate at which they ascend/descend. And it doesn't take alot of processing power, either.

 

[keihaswarrior]

I think it would be nice if the bullets did less damage the further away the target was. Bullets lose their speed (and wounding power) the farther they have to travel. This is especially noticeable with pistol rounds.

Unfortunately, the bullets in INF do the same damage no matter the range.

 

[Dr.J]

i dont think thats always the case keishaswarrior... i may be wrong, but some rounds have too much energy when they first come out of the barrel... eg ive heard that a round fired from an M82 would fly clean through you at point blank, but with reduced energy over distance it can then do more interesting things to you (like try carry parts of you with it, as it may have lost the energy to cut through flesh but still has a lot of foward force)... but then this is mostly guesswork and stuff i remember from conversations with people, so im probably wrong... but i dont think that 'damage' and distance has a linear relationship.

 

[Bushwack]

its called Cavitation, most rounds fired through rifling, acquire a spin to them as they leave the barrel, highest velocity being when the round exits the barrel.
As the projectile travels over distance, physics dictate that the stability the rounds gets from is rotation get less and less, this results in what they call cavitation {there prolly is another more technical term}, which means the nice clockwise spinning that was put on the projectile by the rifling in the barrel lessens and becomes less stabilizing, the round then starts to wobble on its center axis.
Wounding characteristics become a lot higher on a round at the end of its trajectory, since in all likelyhood more of the surface area of the cavitating round will come into contact with the surface of the target, so instead of making a nice lil round hole on entrance, it makes a really big hole and a larger wound cavity.

If i recall correctly, this is why NATO originally banned the use of the 50caliber projectiles against soft targets{ie human infantry}, even though if youre manning a 50 cal and get fired upon, i doubt your going to duck back into your vehicle in search of a lower caliber deterrent against your antagonist

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, this isnt because the 50 cal is a really powerful round per say, its because of the cavitation the round acquires at extreme range.

 

[Dr.J]

yeah there was an article posted before that talked about people splitting in half from M82 fire..

 

[OICW]

its called Cavitation, most rounds fired through rifling, acquire a spin to them as they leave the barrel, highest velocity being when the round exits the barrel.
As the projectile travels over distance, physics dictate that the stability the rounds gets from is rotation get less and less, this results in what they call cavitation {there prolly is another more technical term}, which means the nice clockwise spinning that was put on the projectile by the rifling in the barrel lessens and becomes less stabilizing, the round then starts to wobble on its center axis.
Wounding characteristics become a lot higher on a round at the end of its trajectory, since in all likelyhood more of the surface area of the cavitating round will come into contact with the surface of the target, so instead of making a nice lil round hole on entrance, it makes a really big hole and a larger wound cavity.

If i recall correctly, this is why NATO originally banned the use of the 50caliber projectiles against soft targets{ie human infantry}, even though if youre manning a 50 cal and get fired upon, i doubt your going to duck back into your vehicle in search of a lower caliber deterrent against your antagonist

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, this isnt because the 50 cal is a really powerful round per say, its because of the cavitation the round acquires at extreme range.

.50 BMG isn't banned against infantry. Have you actually read the bloody Geneva and Hague Conventions (both the 1899 Declaration on Expanding Bullets and 1907 Rules of Warfare Declarations)!?

Guess what? All bullets fired from a rifled barrel spin, not "most", the point of it is to keep them stable in air.

All bullets tumble in flesh. Why? Their spin rate isn't fast enough to keep them stable in tissue, which happens to be 400 times more denser than air. The extent of their tumbling or yawing depends on the round in question.

 

[-Freshmeat]

Bullet flight path
I asked about this some time ago:
http://forums.beyondunreal.com/showthread.php?t=122481
Yurch's answer is basically that the flight ballistics are very accurate, allthough I am not sure how the k^distance fits in. According to my book acceleration = (negative constant based on bullet) * velocity^2 for air resistance.

Damage potential
To support KeihasWarrior is some tests that shows that the 5.56mm N does drastically less damage when the bullet speed drops below a certain threshold: http://www.ammo-oracle.com/#velocity. Once velocity is below 2500 fps, the damage potential of the 5.56mm bullet is severely reduced. This assumes that the most important factor is whether the bullet fragments inside the body, making a lot more damage than just passing through. I have no knowledge of the reliability of the source, however, and would like to hear word from some of the professionals around.

This wounding effect could be modelled, but then I would have to leave Infiltration until I got a somewhat faster computer. However, I think that the major problem here is to get reliable data of bullet wound potential.

-Freshmeat (Just interested)

 

[Tiffy]

Can I suggest people try and read some technical books on Internal, Intermediate and external ballistics before makeing statements here.

A round attains its maximum velocity at a point just beyond the muzzel of the firearm as the gases are still acting on the round AND due to heat generated significantly change the local speed of sound thus preventing form drag from initially effecting the round.

All rounds have gyro-scopic presession (Cavitation is something that happens to the boundry layer of air/ water on the projectile and is usually applied to screws on ships as it's damned hard to get something spinning fast enough to produce it in air). The presession means that a round flys a 'cork-screw' path and 'wobbles' for want of a better word. The reason a round presents more surface area to the target at range is due to the fact the rounds orientation doesn't change but its flight path is now significantly downwards. This also causes greater form drag slowing the round more than expected.

A round 'tumbles ' through 180 degrees on hitting anything. This is due to the change of velocity of the tip of the round, coupled with the previously mentioned 'wobble'. This makes the round momentarially unstable causing it to turn 180 degrees. It then stabilises again unless hitting something else with a different density (eg exiting the target) when it'll turn 180 degrees again.

Whilst fragmentation of a round can cause greater wounding of the target the priciple method a target is damaged is due to the temporary and perminant cavities created by the round passing through the target. Spliter fragments tend to have little cavity asscioated with them but can damage blood vessels/ nerves adding to the damage (they also make it a bugger for the surgeon to put you back together agains after the event).

The accepted amount of energy transferred to a target to cause an incapacitating wound is 80j. The NATO 5.56mm round will deliver this out to over 1000m. However the standard NATO helmet can reduce this to around 400m. (Not sure of figure as at work with no reference. I'll check later). Once a round drops to a sub-sonic speed a lot of wounding potential is lost due to the considerable reduced shock wave asscioated with the round. Not sure about that 2500fps figure but it seams high. An M16 is only firing at around 3000fps so that doesn't give you far before your rounds below 2500, around 1000fps would be the transonic boundry.

 

[-Freshmeat]

Thanks a lot, Tiffy. The 80 J figure is highly interesting, as it is a very independent figure (no caliber og minimal velocity). Can you recommend any specific titles on ballistics to read? I have no clue on where to start reading on the subject, but would like to know more about it.

-Freshmeat

 

[Bushwack]

{sarcasmBOTon}

.50 BMG isn't banned against infantry. Have you actually read the bloody Geneva and Hague Conventions (both the 1899 Declaration on Expanding Bullets and 1907 Rules of Warfare Declarations)!? .

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.

Guess what? All bullets fired from a rifled barrel spin, not "most", the point of it is to keep them stable in air. .

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:

..... Their spin rate ....

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

..... more denser than air.....

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

 

[keihaswarrior]

Ug.... ok back on topic.

Whatever you say, the general rule is that the more energy a round has, the more damage it will do. Bullets lose energy as they travel through air. Therefore, damage and distance traveled are inversely correlated.

Bullets often have little nuances about them that cause their wound profiles to change, but overall bullets do less damage the farther they travel.

Also, Tiffy:
Temporary bullet cavities do almost no damage. Most of human tissue is highly elastic, therefore the stretching that occurs with a temporary cavitiy will not be very damaging. This is different for certain things like the liver which does not like to stretch. Also, there is no damage from the supersonic "shockwave" of the bullet in the body. Sonic waves do no damage to the human body at all. Ever had an ultrasound? The sonic waves from that are much much higher in energy than that of a bullet's in human flesh.

Anyway, this is all getting overcomplicated. In general, the farther a bullet travels the less damage it does.

In INF, bullets ALWAYS do the exact same amount of damage no matter if the distance is 500m or 5m. This is obviously not correct.

 

[Bushwack]

KW, temp wound cavities ARE damage, if there wasnt a cavity there when you were born, its not a good thing to have one there after a round enters and exits your anatomy.
there is also the issue of hydrostatic damage { your supersonic shockwave} caused by the transferrence of the rounds energy on impact, remembering that shockwaves are far more damaging in a liquid type environment {the human body is almost 80% water filled}, this results mostly in massive bleeding trauma, nerve damage, destruction of blood vessels, the capillary systems, detachment of muscle and tendon etc.
i have some links for your perusal and they are for the most part civilian medical sources for pistol caliber type gunshot wounds, so use a little deductive reasoning when applying them to MilSpec caliber weapons.

http://medlib.med.utah.edu/WebPath/TUTORIAL/GUNS/GUNREFS.html

http://www.findarticles.com/cf_dls/m3225/7_61/61432939/p1/article.jhtml

http://www.expertwitness.com/search.phtml

http://www.hsph.harvard.edu/hicrc/Firearms.htm

http://www.firearmstactical.com/undeniable-evidence.htm

http://www.cdc.gov/nchs/data/ice/ice95v3/99ch12.pdf

http://police.sas.ab.ca/prl/gun.html#ball

http://www.emedicine.com/med/byname/abdominal-trauma-penetrating.htm

http://www.state.ma.us/dph/bhsre/isp/wrisp/pubs/windata/01wpinjdata.pdf

http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=28193

http://pw1.netcom.com/~dmacp/Fackler_review.html

http://danger.mongabay.com/gunshot_wound_II.htm

 

[yurch]

In INF, bullets ALWAYS do the exact same amount of damage no matter if the distance is 500m or 5m. This is obviously not correct.

RAv2 had a damage modifier based on round energy (velocity^2)

I don't think anyone noticed.

 

[Crowze]

I did. But it's a moot point, since RAv2 doesn't work with 2.9.

*prod*

 

[Tiffy]

Opps sorry Bushwack I knew there was something I was supposed to be doing for someone. Works damned incovienent, gets in the way of gaming.

I'll try and sort something out by the weekend. Sorry