PDA

View Full Version : have you ever heard of eccentric bullets?



raaaid
01-28-2006, 06:36 AM
the seem to change direction once the hit anything, transforming what would be a slight wound into lethal but they are banned by ginebra

dbillo
01-28-2006, 06:54 AM
Who is Ginebra, and why is she banning bullets?

ytareh
01-28-2006, 07:02 AM
Raaid I think you mean "Dum Dum" bullets which tumble on impact causing very serious injuries.I think they are named after a place in India where the British used them.Yes they are banned under the Geneva Convention

Hawgdog
01-28-2006, 07:16 AM
Better stick to flight sims boys, ballisticians you're not.

Max.Power
01-28-2006, 07:24 AM
No, Dum-Dums are bullets that are supposed to expand on contact. This is accomplished through notching the steel jacket at the head with a knife or something.

What raaaid is talking about is tumbling bullets and wooden bullets. I believe, by the geneva convention, projectiles must be stable in flight. Also, the Geneva Accord of Humane Weaponry prohibits the use of exploding, poisoned, or expanding bullets on lawful combatants, I think.

LEBillfish
01-28-2006, 08:15 AM
Guys......seriously do a bit of research as you'll even find military sites that describe all types of projectiles in detail.....

Dum-Dums were originally bullets where the tip of the projectile/slug had the copper jacket removed....This allowed them to expand better. Later and as they most often are today a hole is drilled/formed in the tip.

Trouble with "dum dum's" is the expand much larger then their base diameter......Even worse they tend to fracture up into pieces, those pieces once inside a body zipping off in every direction they seem to choose.

An eccentric round (though never having heard this term applied to a round) I'd assume to mean a round that is poorly balanced about it's diameter.....That would cause a slug to spiral in flight.....and in kind, spiral through the target. All rounds do this to some degree "unintentionally". The Soviet 7.62x39 notorious for it though again "not planned" as that lack of ballance throws off accuracy.

F.Y.I........ALL rounds tumble. However that does NOT mean what you think. Tumbling is where a round strikes a soft tissue target, the impact itself may either ever so slightly deform the tip, or the tissue may cause the path to vere........What then happens is the round will trying to continue on it's path turn sideways. Often rounds are found in victims actually "backward" the tail end of the slug pointing in the direction it was going.

That tumbling results in a wound channel that is much if the slugs diameter was actually as big as its length..........This is why "Flechette" (sp?) rounds where the slug just gives mass falling away are so brutal. The entry wound a pin point as though stuck with a needle....Yet the soft wire bends and twists going in all sorts of wild directions once in......Worse still...When sideways it's length now working as though it was it's diameter.

Ugly stuff all of it.

SeaFireLIV
01-28-2006, 08:15 AM
Raaaid, you are coming out with a lot of questions, non of which you really seem serious on.

Hawgdog
01-28-2006, 08:48 AM
AAAAAAAAAAIIIIIIIEEEEEEEEEE

Google a bit, lads. Google is our friend.

Tully__
01-28-2006, 10:41 AM
raaaid, it's getting out of hand. If it's not directly related to the sim go to google or a forum that covers the topic.

Treetop64
01-28-2006, 11:31 AM
Wow...

Even Tully is beginning to lose his patience.

http://forums.ubi.com/images/smilies/51.gif

Max.Power
01-28-2006, 05:55 PM
Originally posted by LEBillfish:

An eccentric round (though never having heard this term applied to a round) I'd assume to mean a round that is poorly balanced about it's diameter.....That would cause a slug to spiral in flight.....and in kind, spiral through the target. All rounds do this to some degree "unintentionally". The Soviet 7.62x39 notorious for it though again "not planned" as that lack of ballance throws off accuracy.


I would like to see the sources on this, because I think that this would be in violation of the Geneva accord, and ak-47s would be unlawful to use in war.



F.Y.I........ALL rounds tumble. However that does NOT mean what you think. Tumbling is where a round strikes a soft tissue target, the impact itself may either ever so slightly deform the tip, or the tissue may cause the path to vere........What then happens is the round will trying to continue on it's path turn sideways. Often rounds are found in victims actually "backward" the tail end of the slug pointing in the direction it was going.


This is NOT true. Not all rounds tumble when travelling through the media of the body. Most rifle rounds do, but most pistol rounds do not.



That tumbling results in a wound channel that is much if the slugs diameter was actually as big as its length..........This is why "Flechette" (sp?) rounds where the slug just gives mass falling away are so brutal. The entry wound a pin point as though stuck with a needle....Yet the soft wire bends and twists going in all sorts of wild directions once in......Worse still...When sideways it's length now working as though it was it's diameter.
Ugly stuff all of it.

Fackler totally discredited temporary cavitation as a main mechanism for wounding of soft tissues in the study he conduction on the 5.45 soviet round in 1984. His tests were on ballistic gelatin and (ugh) live pigs.

Poor little piggies http://forums.ubi.com/groupee_common/emoticons/icon_frown.gif http://forums.ubi.com/groupee_common/emoticons/icon_frown.gif

http://www.btammolabs.com/fackler/ak74_wounding_potential.pdf

The reason why flechettes were brutal was that they weren't stable before 25 m of flight, and would strike their target side-long. This arrangement would make for incredible amounts of energy transfer and fragmentation of the flechette. These rounds are also illegal by the Geneva Accord of 1899.

Fritzofn
01-28-2006, 06:18 PM
Dum-Dum = small entry wound infront, medium size pizza exit wound

.303 = small entry wound infront, bullet starts tumberling once it enters the body, causing MASSIVE internal bleeding, and as a bonus, a slightly bigger exit wound.

.50 = small entry wound infront, bullet ripps apart everything in the way, and a small size pizza exit wound

Rebel_Yell_21
01-28-2006, 06:44 PM
Originally posted by Treetop64:
Wow...

Even Tully is beginning to lose his patience.



I hope so....

J_Weaver
01-28-2006, 08:24 PM
I'm not sure what this has to do with PF, but what the heck. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

Dum-dum, is basically an out of date term for a hollow point or jacketed soft point bullet. The whole purpose is for the bullet to expand more quickly upon impact. Although in some situations this might be less than ideal.

As far as bullets tumbling go, well thats hard to tell. For starters a bullet should not tumble in flight. The purpose of rifling is to make a bullet spin so that it won't tumble. A tumbling bullet is extremely inaccurate. You can't tell where they are going to go.

Now once a bullet impacts a target all bets are off. Ribs and other bone could make a bullet tumble or change course, but there is no way to tell what will happen.

F4U_Flyer
01-28-2006, 11:52 PM
And i thought they were old bullits that can't find there car keys ! http://forums.ubi.com/images/smilies/35.gif

LEBillfish
01-29-2006, 12:00 AM
You must be kidding right?....

Manufacturing intolerance

All do, infact pistol sized more

5.45 also has/had a steel core and hollow tip

bunk....flechettes are stable....they bend once inside otherwise they'd lose energy too much before hand to be of any use



Originally posted by Max.Power:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by LEBillfish:

An eccentric round (though never having heard this term applied to a round) I'd assume to mean a round that is poorly balanced about it's diameter.....That would cause a slug to spiral in flight.....and in kind, spiral through the target. All rounds do this to some degree "unintentionally". The Soviet 7.62x39 notorious for it though again "not planned" as that lack of ballance throws off accuracy.


I would like to see the sources on this, because I think that this would be in violation of the Geneva accord, and ak-47s would be unlawful to use in war.



F.Y.I........ALL rounds tumble. However that does NOT mean what you think. Tumbling is where a round strikes a soft tissue target, the impact itself may either ever so slightly deform the tip, or the tissue may cause the path to vere........What then happens is the round will trying to continue on it's path turn sideways. Often rounds are found in victims actually "backward" the tail end of the slug pointing in the direction it was going.


This is NOT true. Not all rounds tumble when travelling through the media of the body. Most rifle rounds do, but most pistol rounds do not.



That tumbling results in a wound channel that is much if the slugs diameter was actually as big as its length..........This is why "Flechette" (sp?) rounds where the slug just gives mass falling away are so brutal. The entry wound a pin point as though stuck with a needle....Yet the soft wire bends and twists going in all sorts of wild directions once in......Worse still...When sideways it's length now working as though it was it's diameter.
Ugly stuff all of it.

Fackler totally discredited temporary cavitation as a main mechanism for wounding of soft tissues in the study he conduction on the 5.45 soviet round in 1984. His tests were on ballistic gelatin and (ugh) live pigs.

Poor little piggies http://forums.ubi.com/groupee_common/emoticons/icon_frown.gif http://forums.ubi.com/groupee_common/emoticons/icon_frown.gif

http://www.btammolabs.com/fackler/ak74_wounding_potential.pdf

The reason why flechettes were brutal was that they weren't stable before 25 m of flight, and would strike their target side-long. This arrangement would make for incredible amounts of energy transfer and fragmentation of the flechette. These rounds are also illegal by the Geneva Accord of 1899. </div></BLOCKQUOTE>

Max.Power
01-29-2006, 12:19 AM
Fish, you are greatly mistaken about a lot of things. The following is what I could dig up sources for on short notice. The rest of what I'm saying to you is the truth. Flechettes take about 25 meters to stablize when shot from a 40 mm grenade launcher, which is, I think, the ONLY military application of flechettes ever brought to bear in wartime.

Go onto this site and tell me which ones tumble more.

http://www.firearmstactical.com/wound.htm

Near the bottom there will be a series of images links. Review them all. After you are finished, come back and tell me which ones tumbled, which ones fragmented and which ones remained straight.

Also, note that a human torso averages about 400 milimeters in width. That is about 40 cm, or just over a foot. You can help yourself even more by telling me which ones tumbled significantly in the boundaries of the body.

NonWonderDog
01-29-2006, 01:29 AM
LeBillfish is (partially) right about one thing, though, the 5.45x39 round used in the AK-74 was designed *specifically* to tumble within the body and cause larger wounds than the small caliber would indicate. It's since been shown over and over that temporary cavities don't really cause too much damage at all... and the Russians seem a bit disillusioned with the round... but whatever.

The Geneva Conventions and their amendments have never been interpreted as banning the use of rounds that tumble in the body, regardless of whatever momentary media outrage at "tumbling Russian torture bullets" or whatever it was.

Max... in the image links you've posted, every FMJ or ball round either tumbles or fragments. JHP and JSP rounds can't and don't. Isn't that just common sense?


Anyway, weren't 5.56 NATO rounds fired from the first generation M16s with inadequate rifling quite famous for being unstable in flight and causing obscene wounds at short range? I don't remember all the specifics. In any case, they fixed it because the gun was horribly inaccurate, not because it violated the Geneva Conventions.

Hoatee
01-29-2006, 02:06 AM
Bullets have character, it would appear.

Max.Power
01-29-2006, 04:18 AM
Max... in the image links you've posted, every FMJ or ball round either tumbles or fragments. JHP and JSP rounds can't and don't. Isn't that just common sense?


The .45 FMJ round on that site does not tumble.



Anyway, weren't 5.56 NATO rounds fired from the first generation M16s with inadequate rifling quite famous for being unstable in flight and causing obscene wounds at short range? I don't remember all the specifics. In any case, they fixed it because the gun was horribly inaccurate, not because it violated the Geneva Conventions.

All 5.56 rounds fragment at medium ranges because of the design of the round (the m855 may fragment at 200 meters with a 20" barrel). The 5.56 round has quite a pronounced 'cannelure'. The cannelure is an indent that is etched into the side of the bullet that engages a rim on the neck of the casing. When the bullet turns sideways in the body, the jacket ruptures at the cannelure, the integrity of the bullet is lost, and the lead core flies apart. This causes very complicated wounds.

The 5.45 soviet round was designed on a false understanding of this principle, and so the bullet was designed to tumble rather than to 'accidentally' break apart. I've never heard of the 'torture' bullet thing before, but that's really funny in the face of what kinds of wounds the 5.56 bullets routinely produce.

For more information on 5.56 rounds, check out this site:

http://www.ammo-oracle.com/body.htm

It has really good graphical representations of these concepts, including snapshots of the fragmentation of bullets at various velocities, charts comparing different 5.56 load on various aspects, and information on wounding mechanisms.

BfHeFwMe
01-29-2006, 05:05 AM
Eccentric bullets

Yeah, seen em. Those are the ones that usually get jammed tight in the actions of fancy expensive jam proof guns. http://forums.ubi.com/images/smilies/59.gif

x6BL_Brando
01-29-2006, 05:36 AM
Geneva Accord of Humane Weaponry

Up there with the classics, oxymoron-wise? http://forums.ubi.com/images/smilies/51.gif

"For a little bullet, the 5.56 bullet produces quite dramatic wounds. While the traditional 30-06 caliber bullet of the M1 Garand and 7.62 bullet of the M14 rifle would immediately knock a man down, the 5.56 bullet instead enters the body, quickly turns sideways after passing through only 4" of flesh, then breaks in two major pieces, as well as many smaller fragments. During the Vietnam War, soldiers reported that shooting an enemy soldier with the M16 did not kill as quickly as the old 30 caliber weapons. Instead soldiers would follow a massive trail a blood a few feet away from where the enemy soldier had been hit to find him dead from massive blood loss. This light-weight cartridge permits soldiers to carry more ammo, but is not as effective at long distances as heavier cartridges and does not penetrate steel as well. The low recoil permits quick follow-up shots and minimal muzzle climb during automatic fire."
http://www.bobtuley.com/terminal.htm

Vivid enough Raid? http://forums.ubi.com/groupee_common/emoticons/icon_rolleyes.gif

SeaFireLIV
01-29-2006, 06:03 AM
yea, `humane-weaponry`. I guess being chopped in the head by a sword`s better then? how can anything that forces a guy to die (apart from old age) when he doesnt want to, be Humane? Anyway, raaaid`s probably forgotten about this and is working on his next question...

Max.Power
01-29-2006, 06:50 AM
re: humane weaponry

Because the majority of casualties of war survive, and so you have a choice... Are you going to design a weapon to kill or wound cleanly, or are you going to design one to bring disability and misery? Chlorine gas is an example of an inhumane weapon.

re: .30 calibre rounds knock a man down

They don't knock people over. If a bullet was powerful enough to knock a man over, the recoil from the rifle would be as powerful. This is a classic illustration used in basic kinematics to describe Newton's third law. People fall over for a variety of reasons, none of which have to do with the force of the bullet. That firearms tactical site I posted earlier has an interesting article on the subject, in the form of a study conducted by the FBI. I think it's called 'Handgun Wounding Effectiveness.' The study itself is about the choice of handgun calibre, but there is a lot of general information about bullet wounds and what happens to people when they're shot.

edit: the study was conducted by the FBI, not the intelligence agency.

raaaid
01-29-2006, 06:59 AM
i dont want to get you upset tully so ill stop posting offtopic

anyway i was wondering if any plane of the game carries them because some bullets make a spiral trace and i see no point in making the gases hole in one side of the bullet

Max.Power
01-29-2006, 07:05 AM
Spiral smoke trails result from the spin of the shells. Cannons with rifled barrels produce a spin along the axis perpendicular to the plane of the radius of the bullet. These bullet spin like an american football in flight, which stablizes the bullet gyroscopically...

so, it is not that the bullets tumble that creates that pattern, it is for precisely the opposite reason: Those patterns appear because the bullets are spin-stablized.

SeaFireLIV
01-29-2006, 07:23 AM
Originally posted by Max.Power:
re: .30 calibre rounds knock a man down

They don't knock people over.

This is true and a common misconception bought from hollywood, I reckon (it`s the only place where I see men being blown away by bullets - Last man Standing for eg (still a good film, just not very realistic). I recently had to explain in detail this point to someone complaining that a game was wrong because people weren`t falling away from being shot by a sub-mg or mg.

LEBillfish
01-29-2006, 07:30 AM
Originally posted by Max.Power:
Spiral smoke trails result from the spin of the shells. Cannons with rifled barrels produce a spin along the axis perpendicular to the plane of the radius of the bullet. These bullet spin like an american football in flight, which stablizes the bullet gyroscopically...

so, it is not that the bullets tumble that creates that pattern, it is for precisely the opposite reason: Those patterns appear because the bullets are spin-stablized.

OK....that caps it for me in this thread........I think raaaid has found a friend.

Very few WWII projectile based arms for aircraft would not be run through rifled barrels.,...Those not without even looking I'd bet had spiral groovingon the round itself much like a foster slug.

Get this tumbling idea out of your head.....as it has nothing to do with wanting rounds to tumble in flight as then you'd lose accuracy and energy.....

The spiral smoke trails you are seeing "in the sim" are supposed to be representations of vapor trails left by rounds "out of balance"....Again, manufacturing intolerance or a hundred other variables that cause a condition when spinning of not running perfectly on the bullets axis so it spirals or screws around the projectiles "flight path" axis. As it loses energy it will degrade even further.

Done with this thread......will I ever learn http://forums.ubi.com/images/smilies/16x16_smiley-indifferent.gif

Max.Power
01-29-2006, 03:50 PM
Originally posted by LEBillfish:
OK....that caps it for me in this thread........I think raaaid has found a friend.

Very few WWII projectile based arms for aircraft would not be run through rifled barrels.,...Those not without even looking I'd bet had spiral groovingon the round itself much like a foster slug.

Get this tumbling idea out of your head.....as it has nothing to do with wanting rounds to tumble in flight as then you'd lose accuracy and energy.....

The spiral smoke trails you are seeing "in the sim" are supposed to be representations of vapor trails left by rounds "out of balance"....Again, manufacturing intolerance or a hundred other variables that cause a condition when spinning of not running perfectly on the bullets axis so it spirals or screws around the projectiles "flight path" axis. As it loses energy it will degrade even further.

Done with this thread......will I ever learn http://forums.ubi.com/images/smilies/16x16_smiley-indifferent.gif

Yeah, 'cause every tracer is out of balance. Hahaha. That would make for some sweet tracing. Nice work, Einstien.

I see you didn't respond to my above post on the behaviour of bullets inside the body. You're ignorant, confrontational, and resistent to improving. I sincerely hope that you don't come back. The adults can now have a serious conversation.

P.S. It may be helpful to read the contents of my post before replying to it.

FPSOLKOR
01-30-2006, 01:12 AM
As a doc who spent some time in €œhot spot€ I can tell you what effects have different bullets on different distances. Most devastating effect at close distance has 12 gauge shotgun, especially if enters body from area without flack jacket, if a man wears one. Usually person would die in a couple of days. AK-74 is the second best €" it stops man where it hits him. He is still alive, but no longer active. Usually he is so busy with his oun health so that he cant even fire at you when you are standing close. Third is 5,56 €" can€t tell which gun exactly. A man hit with it usually has a severe problem with hit area, but still is capable of shooting and moving. 7,62 are sure kill if they hit correct spot, but I€ve seen soldiers hit in the head with it and still live. Brain was not severely damaged, while 5,45 would make a minced meat out of it. On the long distance it is all vise versa. Well, really, what the hell is the difference what hit you at the speed of 1 km\s in the head, if closest doc is 100 km away? http://forums.ubi.com/images/smilies/784.gif Now, back to sim: unstable bullet would not have necessary penetrative power to make damage to aircraft. That is the reason for making il-2 armor so effective. Even if it was penetrated, bullet would loose most of its power and brake in bits from internal tension. On the other hand I€ve met some memoires where spit pilots said that they were a lot more afraid of mgun fire than hurricane drivers, since bullet would easely penetrate wooden skin of hurry and would go bouncing inside of spits fuselage.

Max.Power
01-30-2006, 02:57 AM
That's really interesting, FPSOLKOR. Some of it is counter what the fakler study found- well, the bit about the 5.45 round at any rate.

The 5.45 round is a deep penetrator, and it yaws inside the media of the body, but temporary cavity was discredited as a consistent/significant wounding mechanism. Without knowing more about the circumstances of the shootings, I could not begin to surmise why your findings contradict the study. Where you say that the soldier is too involved with his own state of being to return fire suggests a psychological aspect, maybe that would be a place to begin.

Very interesting.

FPSOLKOR
01-30-2006, 04:12 AM
Originally posted by Max.Power:
That's really interesting, FPSOLKOR. Some of it is counter what the fakler study found- well, the bit about the 5.45 round at any rate.

The 5.45 round is a deep penetrator, and it yaws inside the media of the body, but temporary cavity was discredited as a consistent/significant wounding mechanism. Without knowing more about the circumstances of the shootings, I could not begin to surmise why your findings contradict the study. Where you say that the soldier is too involved with his own state of being to return fire suggests a psychological aspect, maybe that would be a place to begin.

Very interesting.

Not sure myself, but i studied this question, and most common to these articles is that all of them suggest that person would get that wound and this effects after "pig leg" studies as well as long term assesment is done. I've seen all of this straight on the battlefield... What i can suggest, is that 5,45 bullet makes large cavity and involves more nervous endings by means of temporary cavity, so the person gets a lot more chanses to get into traumatic shock. circumstance: We were attacked by about 150 men with NATO firearms (we found m16, FN FAL and steyr AUG) as well as ak-74 and BORZ, we (100 men) had AK-74, SVD, PM. So situation was clearly almost even.Being involved in a fight i saw everything with my own eyes.

raaaid
01-30-2006, 06:54 AM
my doubt is wether the spiral tracers are eccentric or not, i believe so because they look like trully making a spiral trajectory, not like if the gases are coming from a side hole

when an eccentric bullet hits the enemy plane it keeps spinning at high velocity , but its center of gravity is not the center os spin, which makes the bullet go in a very open spiral(some antigravity related here, which makes me supose this bullets were inventerd by 1900), when it moves within the air the difference between the axe of spin and the center of gravity is smaller so the spiraling behaviour is minimal

raaaid
01-30-2006, 07:41 AM
so instead of making a straight trajectory within the enemy plane they made a very open advancing spiral making maybe 1000 times more damage than the ordinary ones

its remarkable that being banned by geneva were only used by hitler and stalin

Tully__
01-30-2006, 10:17 AM
Originally posted by raaaid:
so instead of making a straight trajectory within the enemy plane they made a very open advancing spiral making maybe 1000 times more damage than the ordinary ones

its remarkable that being banned by geneva were only used by hitler and stalin

You're jumping to totally unrealistic conclusions based mostly on game graphics. You've also mis-understood the physics involved again. http://forums.ubi.com/groupee_common/emoticons/icon_rolleyes.gif

major_setback
01-30-2006, 11:22 AM
"the seem to change direction once the hit anything, transforming what would be a slight wound into lethal but they are banned by ginebra"

???You don't by any chance mean the 'genebra' convention do you?


<span class="ev_code_GREY">.</span>?
http://forums.ubi.com/images/smilies/51.gif

Hawgdog
01-31-2006, 06:04 AM
This thread makes the three stooges look brilliant.

vanjast
01-31-2006, 10:34 AM
Yep, eccentric bullets might have been used by our military in the 'Bush-War'(no relation to you know who) South Africa.
AFAIK thay found that our R1 7.62mm bullets would go right through the 'target', so with the R4 (5mm I think) rifle they gave it an unbalanced bullet that had a slight 'tumble' in flight. Not as accurate but when it hit something it tore it apart.
I think the object of it was to get around one of the world regulations on the use of 'dum-dum' bullets. The effect was very much the same though.
http://forums.ubi.com/images/smilies/16x16_smiley-indifferent.gif

raaaid
01-31-2006, 12:01 PM
this is going off topic http://forums.ubi.com/groupee_common/emoticons/icon_mad.gif

my main point is wether the spiral tracers are eccentric or just expell the gases by a side hole

seeing real footage makes me think that the radius of the spiral is too big what would point to eccentric bullets

physics also say that an eccentric bullet will have that spiral behaviour

an eccentric bullet in vacuum will spin aroun its center of gravity but in the atmosphere the air will make the bullet tend to spin around its center of volume and once hitted the target it will almost exactly spin around its center of volume

being different the center of gravity and the center of volume in which the bullet spins the effect is that the center of gravity is not in the center of spin, the effect will be the one seen in the game by spiral tracers, once hitted the target the radius of the spiral will increase dramatically

in fact if the game was well modelled spiral tracers at low altitude should have a bigger radius than those shot at higher altitudes because of air density

in the tracers of this game is not taken into account the wind that quickly will make the trace beahve like smoke of a cigarrete, umpredictable

Cajun76
01-31-2006, 01:15 PM
raaaid, an object like a bullet cannot rotate from a piont outside it's own m***. Even a hammer, thrown from one end or the other will rotate around center m***, which is near the head. But it cannot rotate around a piont beyond the end of the hammer.


X-0---x^ = yes

0~X-----x^ = no

Cajun76
01-31-2006, 01:20 PM
Remember, the a/c is also traveling forward, so the gun camera dosen't record what hapens behind the plane.

And the tracer smoke is merely coming out of one side of the round. That's why the spiral stays tight, and the rounds stay on target instead on wobbling

Max.Power
01-31-2006, 11:34 PM
I have been doing some research on the subject and there are a lot of theories as to why there were spiral smoke trails... The most interesting one was that the spinning bullet creates a rotating wash around the bullet, and a swirling vortex behind it, much like the P-effect. This vortex is responsible for spinning the smoke behind the round, creating a spiral pattern.

I don't know why it happens, but I can tell you that it isn't because the bullet has a hole cut in it to expell jets of gas out the side. It also is not because the bullet is tumbling or rotating off axis. Either of the above would create huge accuracy problems, and in the case of the latter, skew the bullet trajectory, rendering their effect as tracers useless.

raaaid
02-01-2006, 05:17 AM
this is getting interesting, vortex, imposibility to explain a fact,

well ill try with another example to prove than the spiral tracers are eccentric bullets:

imagine you are holding a box with a spinning heavy eccentric weight

as it spins it will tend to make a circle in your hands, axle:x ,center of gravity of the boxhttp://forums.ubi.com/groupee_common/emoticons/icon_redface.gif

x-----o

the center of spin or axle of the box will be somewhere outside the box

the box is the bullet, your hands holding the box are the air

of course this wouldnt work in vacuum space so it doesnt contradict newton at all

Max.Power
02-01-2006, 09:56 PM
Your theory is of the post-hoc variety. I do not see any reason to believe that the bullets are eccentric over and above any other explanation. Moreover, I see ample reason why these bullets should not be eccentric.

Case and point, a solid bullet flying sideways through an aluminum airframe would produce a hole roughly the size and shape of the bullet itself. Moreover, the sideways orientation of the bullet would decrease the bullets ability to penetrate harder structures. Also, this orientation of the bullet would make the round extremely innaccurate. Statistically speaking, do you think that a sideways or 'eccentrically' oriented bullet that hits 1/4 of the time at 200 meters but produces twice the superficial damage is a worthwhile development? No. Convergent with this line of argument, an eccentrically oriented bullet would lose energy to the air it was displacing by increasing its frontal surface area to its airflow.

It is NEVER advantageous to have a bullet that flies sideways over a bullet that is designed correctly, especially when the bullets are explosive or armour piercing. The only time you want a bullet to give up all of its energy is when it's travelling through a soft body, but even the benefits of that are highly contested.

Ballistic4N6
02-02-2006, 06:35 PM
A spin stabilized projectile will remain so in flight until some surface or object tips the bullet to cause destabalized attitudes. It doesn't take mutch, a wooden match stick or even a corn chip will tip the nose off axis. The force needed for this is slight, and is fact is not intuitive to those non-ballisticians.

I have studied under Fackler in a number of wound-ballistic wrkshops, and one of the surprising facts that he ran into as a surgeon in Viet Nam, was that the troops hit through and through in the chest (not touching major artery or spine) with the 7.62x39mm bullet, require only anti-biotics and bandaging. This was an example of the wound lethality difference of a projectile passing through less vasculated tissue such as lung, but was very severe one if the liver or brain was hit.

The reason that the Soviets designed a bullet such as used in the AK-74, was that it was primarily designed for urban warfare, and the the fact that a moderate powered cartridge that shot a bullet that could easily be destabalized down range if missing a target, was judged a pluss in city fighting. The "older" larger 30 cal 7.62x39 bullet had sufficient mass to keep flying down the street even if missing a target and impacting a street or building.

FPSOLCOR has experience similar to mine, my 'hot zones" being in a few US city crime labs.

And BTW, A person that has been hit with any "lethal" shot will not move perseptably from the hit. He will instead drop like a bag of potatoes.

FPSOLKOR
02-03-2006, 03:17 AM
and BTW, A person that has been hit with any "lethal" shot will not move perseptably from the hit. He will instead drop like a bag of potatoes.
If he is dead, that is, although i've seen once a man hit with a SVD bullet (7,62x54) through a heart moving for about a minute or so... And i do believe that a pilot could bring a plane home and die after landing. The bullets force and habbits would change twtd (time from wound to death)drastically.

vanjast
02-03-2006, 11:53 AM
Originally posted by Cajun76:
raaaid, an object like a bullet cannot rotate from a piont outside it's own m***. Even a hammer, thrown from one end or the other will rotate around center m***, which is near the head. But it cannot rotate around a piont beyond the end of the hammer.


The boomerang is an interesting concept. I you gave the bullet a small winglet on one side only and got it to tumble in flight. You probably could make it rotate outside it's centre of gravity. something like barrel roll flight dynamics.

http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif

Ballistic4N6
02-03-2006, 03:07 PM
Actually you are not far off. Many bullets, typically "short" pistol caliber bullets are over-spin-stabilized to the point that doppler tracking radar picks up a secondary occilation of the bullet as it travels downrange. The bullet is spinning mightily on its own axis, but it is also "circling" down the flight axis, much like a barrel roll!

Skoshi Tiger
02-04-2006, 07:48 PM
As far as bullets tumbling go, well thats hard to tell. For starters a bullet should not tumble in flight. The purpose of rifling is to make a bullet spin so that it won't tumble. A tumbling bullet is extremely inaccurate. You can't tell where they are going to go.


The cores of projectiles used in the MK7 303 round had an aluminium tip (sometimes even wood pulp when times got hard!) with lead base all covered over with a copper jacket. This meant that the projectile could be spin stablized by the rifling but when the round hit the tip of the round would decelerate quicker than the base causing the projectile to tumble after impact and transfer as much of the energy of the round as possible into the target.

It was a way around not using the 'inhumane' and banned 'dum dum' bullets and getting similar results.

Ideas like this are fairly standard in bullet design nowadays.

Also after about 2500 fps most of the dammage comes from hydrostatic shock. In this case the damaged area is much larger than the path of the projectile. The tumbling reduced the projectile from over penetration, where the round passes through the target with out transfering the distructive energy to the target

The-Pizza-Man
02-05-2006, 09:27 PM
I've read that before. They banned expanding bullets only to have someone invent a bullet that is even worse, one that tumbles and fragments.

SnapdLikeAMutha
02-05-2006, 10:39 PM
OH this is brilliant!

Gas filled tracers!

Ginebra!

Eccentric bullets!

This thread has it all http://forums.ubi.com/images/smilies/88.gif

Unfortunately it's about seven weeks too early...

FWIW I believe that, when people ARE knocked down by bullets, it is due to the force of the impact being transferred to the nervous system and causing a temporary shutdown of motor control.

JG301_nils
02-08-2006, 03:39 AM
Originally posted by raaaid:
the seem to change direction once the hit anything, transforming what would be a slight wound into lethal but they are banned by ginebra

No, ... and yes it's Genebra

Max.Power
02-08-2006, 04:33 AM
I think what he was referring to was the Geneva convention. I don't think that either Genebra in Brasil or in Switzerland have the same claim to fame as Geneva. Do they?