Effects of High Velocity Needle Rounds?

[Korto]

What I’m asking about is the effect on the human body of being hit by a high-velocity needle. This concerns a very common weapon in some ongoing stories I'm writing.

The ‘needle rounds’ fired are shaped much like a needle—needle-pointed, thickening through the shaft, and very smooth all over. It’s been designed to be aerodynamically stable and accurate (tiny fins or whatever). The construction is very strong, but if it does fail, it shatters.

While there would obviously be a wide range of different rounds, assume for simplicity three standard types:
Pistol needle: muzzle velocity 1000m/s, mass 3g, length 50mm, max diameter 2mm
Rifle needle: velocity 3000m/s, mass 5g, length 75mm, max diameter 3mm
Heavy needle (from their version of a heavy machine gun): velocity 5000m/s, mass 10g, max diameter 4mm

Finally, another weapon is gaining popularity—it fires shotgun cartridge-sized hollow-charge rounds, which create a metal jet about 1mm in diameter.


An armoured man—who these rounds were designed for—would be wearing hard plate armour combined with a forcefield. This armour is very strong—the protection granted by standard infantry armour is equivalent to a modern day armoured personnel carrier (don’t ask me what type. I don’t know. It’s just a rule of thumb), and that’s before the forcefield—but when it fails it shatters like ceramic. (Yes, it uses a very similar material as the needle round itself).
The forcefield can be ignored for this—obviously its protection has failed, and can be completely discounted.

My assumption is that if a needle penetrates armour, it would cause a spray of razor-sharp armour fragments, which would chew a much larger hole than the needle alone could.
If a needle hits an unarmoured man, I’ve got a feeling that unless it hits something vital, it would tend to pass straight through without doing significant damage. If it hit bone, I guess it would shatter the bone and send splinters through the body.


I’m looking for your best guess, for someone (armoured and unarmoured) being hit in different parts of the body:
* What it’ll feel like
* What kind of damage it would do (including how lethal it would be).

[Simon_Jester]

1000 m/s is in line with the muzzle velocity of existing cannon.

The 3000 and 5000 m/s needles may tend to crater rather than penetrate when they strike a hard surface.

Except... Um. I did a little math and it looks like your needler rounds have a density approximately ten times that of tungsten or depleted uranium. And that's assuming they're cylinders equal in radius to their maximum radius all along their length. Obviously they're not, so they're even MORE than ten times as dense. What the hell are you making them out of?.

If they're made out of some exotic ultra-unobtainium matter which is not found on the periodic table known to turn-of-the-millenium science, maybe they can retain their structural properties and penetrate armor even at speeds of three or five kilometers per second.

Also, I would not assume the forcefield irrelevant unless it behaves like a very soft-SF "bag of hit points shield" which is totally effective at stopping everything until it abruptly fails and does nothing...

[Sky Captain]

3000 m/s packs similar energy equivalent mass of high explosive would have. My guess would be if hit by 5g rifle needle effect may be similar to being hit by 5 g shaped charge explosive device. Severe injury at minimum.

[Captain Seafort]

3000 m/s packs similar energy equivalent mass of high explosive would have. My guess would be if hit by 5g rifle needle effect may be similar to being hit by 5 g shaped charge explosive device. Severe injury at minimum.

Against concrete or armour, maybe. Against soft tissue it would go straight through and out the back. It wouldn't be good for your health, but the effects would be nothing like being hit by a small grenade.

[Simon_Jester]

I've always been a bit unsure about that. Remember, we're talking about a 3mm or 4mm dart- narrower than a standard rifle round but not vastly so. Even if it isn't greatly slowed passing through the body, and retains most of its kinetic energy, it will still create hydrostatic shock waves- possibly very nasty ones, because the speed of sound in water is roughly 1500 m/s. Think of this thing creating a sonic boom inside the body.

Hypervelocity 'dart' ammunition might well turn out to be the worst of both worlds from the point of view of a human target- ammunition that consistently inflicts gory, killing wounds, AND which will routinely penetrate both cover and the human body to maim and kill targets behind those things... and behind those, and behind those.

[Batman]

Hydrostatic shock is a myth. Sure, the bullet will do a lot of damage...to the tissue it actually passes and surroundings. The shockwave would travel along the blood vessels instead of simply rupturing them at/close to the point of entry why, exactly?

[Elheru Aran]

Remind me why making real life 'needler' guns won't work? The problem of accelerating such a fine projectile to sufficient KE to harm/kill people on a small enough, man-portable scale?

[Lord Revan]

Remind me why making real life 'needler' guns won't work? The problem of accelerating such a fine projectile to sufficient KE to harm/kill people on a small enough, man-portable scale?

A sharp high velocity round has high likelyhood to over penetrate on soft targets causing relativly minor damage compared to a bullet and if not quite big has likelyhood to just shatter if hitting a hard target, so basically either the "needle" isn't big enough to really do damage or it's too big to be manportable even my military standards. The Sabot shells some cannons use are essentially big darts but they're too big to be used in man portable weapons too.

[Purple]

Remind me why making real life 'needler' guns won't work? The problem of accelerating such a fine projectile to sufficient KE to harm/kill people on a small enough, man-portable scale?

Several reasons.
1. Flachettes, for that is the name for this sort of ammo tend not to work well with rifling due to the extreme speeds. So you have to either forget accuracy or stabilize them with fins and end up with a very complicated and this expensive bullet.

2. While we are at accuracy small light projectiles (for in real life we don't have neutronium darts) these projectiles just had too little momentum and would thus lose a hell of a lot accuracy just flying around.

3. Because they lack momentum but have a lot of kinetic energy they tend to not hurt much. A modern bullet kills not by penetrating your body but by tumbling, expanding or breaking apart on impact and consequently shredding many times its caliber in flesh as it rips a gruesome hole through your insides. Flachettes meanwhile tended to just fly strait through and out the back leaving a neat hole. So unless you manage to hit a vital organ the person survives and can keep fighting.

---

Really though these rifle designs are going into territory where we really shouldn't be talking about mechanical damage. At the kind of velocities these things will be flying materials tend to behave wrong. Like tank rounds only fly at about 1/3 of his rifle bullets and when they hit tank armor it behaves like a semi liquid. These things might well just shatter on impact. Hell they might well ablate horribly in the air from the friction!

[Batman]

Actually to an unarmoured human modern military bullets will simply drill a hole through the body because a)they're designed to defeat body armour and b) the Geneva Conventions say the bullet expanding, breaking apart or stuff like that is a big no-no.

[Jub]

With regards to damage and overpenetration, I wonder if having these types of rounds trail a length of beaded wire would increase their effectiveness? I'm thinking the beads would be made of something like pellets of lead or steel and be slightly larger than the end of the needle. The hope being that shortly after the needle penetrates any armor and opens a way for the beads, the beads impact the target and mushroom out causing extra damage. Obviously finding a way to make such rounds work would be highly challenging, but so would creating a needle that survives being launched at those insane speeds.

[Lord Revan]

With regards to damage and overpenetration, I wonder if having these types of rounds trail a length of beaded wire would increase their effectiveness? I'm thinking the beads would be made of something like pellets of lead or steel and be slightly larger than the end of the needle. The hope being that shortly after the needle penetrates any armor and opens a way for the beads, the beads impact the target and mushroom out causing extra damage. Obviously finding a way to make such rounds work would be highly challenging, but so would creating a needle that survives being launched at those insane speeds.

problem with something like that is that the wire would negatively effect your accuracity in anything but extreme close range (read:melee range) remember that these needles aren't gonna be that big so having a set loose weights trailing behind them would effect the balance immensly (as even the wire would be similar weight to a signifigant portion of the weight of needle). Not mention it would create a another level of complexity to the projectile.

Bullets work because they're in the end really really simple.

[biostem]

Is there a reason why you'd want to use a needle-shaped projectile vs, say, a simple ball bearing? Also, would it be more stable to have the wider/blunter end be the front/head, and the pointed part trailing, sort of like a falling raindrop shape?

[Sea Skimmer]

Remind me why making real life 'needler' guns won't work? The problem of accelerating such a fine projectile to sufficient KE to harm/kill people on a small enough, man-portable scale?

Velocities over about 2000m/s are always going to produce really crummy results with existing gunpowder technology. The propellent charge to projectile mass ratio begins to skyrocket around that point. You can go considerably higher with more exotic chemical fueled launch systems like a combustion light gas gun, but they all have there own problems in anything remotely man portable. All of them depend on some kind of active burn reaction control too. Otherwise the chamber pressure will shatter any possible gun.

A USAF lab actually rebuilt a 20mm cannon to fire 7.62mm bullet at 3000m/s (intended for use in space) and that gives some idea of the problem already, as the charge to mass ratio was about 26 to 1. The 7.62mm round is being fired from about 600lb of cannon at this point. 5000m/s would be about impossible because its too close to the actual burning velocities of the gunpowders. It would make more sense to fire a shaped charge at that point.

[Korto]

Except... Um. I did a little math and it looks like your needler rounds have a density approximately ten times that of tungsten or depleted uranium. And that's assuming they're cylinders equal in radius to their maximum radius all along their length. Obviously they're not, so they're even MORE than ten times as dense. What the hell are you making them out of?.

If they're made out of some exotic ultra-unobtainium matter which is not found on the periodic table known to turn-of-the-millenium science, maybe they can retain their structural properties and penetrate armor even at speeds of three or five kilometers per second.

Also, I would not assume the forcefield irrelevant unless it behaves like a very soft-SF "bag of hit points shield" which is totally effective at stopping everything until it abruptly fails and does nothing...

Aaargh! (Desperately checks maths...)

OK, the pistol round's badly off, the rifle a bit off, and the heavy is fine. I'll save my maths in case of further trouble.
Re-picture a needle as being by length 15-20% front cone, and the rest straight shaft (with whatever fins or whatever it needs for straight flight).

The needles have a shell of 'Compo' (below), the wall ranging in thickness from 0.2 to 0.4mm, and are typically filled with lead, although tungsten, osmium, etc, are used on occasion.
Ceramic Steel Composite (or 'Compo'), is a material which, while only 2/3 the weight of normal steel, is amazingly strong, hard, tough, resistant to abrasion, and only has a few minor down-sides (eg. can't be welded, a bitch to machine, shatters when it fails). As a strength example, the variety used for personal armour, 3mm thick of it gives all the protection of a modern-day APC.
Pistol: 50mm long, 3mm thick
Rifle: 90mm long, 3mm thick

The force-field works by absorbing energy from the attack and expressing it as a powerful localised force against the attack. This is most of the time a cross-current, powerful enough to push aside and break a needle or even a shaped-charge jet. But the direction of the current is random and uncontrollable. It can also push directly against the attack (even stopping it right in its tracks). It can also be in the same direction of the attack, creating effectively a temporary hole.
Also, the field has trouble dealing with 'High pressure' attacks--extreme amounts of energy in extremely minute areas. These attacks will often burn out the local field emitters. The attack will still not generally get through (except when the weapon is significantly overpowered compared to the armour), as too much energy was used to burn the emitter, but a field needs a complete shell coverage to be up--once enough emitters are destroyed that it can't maintain a complete shell, the whole field fails. Emitters are expensive tech, but good personal armour comes with a generous amount of redundant emitters.


PS- Biostem, the last paragraph above deals with the storyline reason. The real reason is for some reason I like the concept. Also, I like the contradiction of this powerful weapon which has minimal effect (compared to a more normal projectile) on someone unarmoured, so if there's argument over it, I'll go the view that hydrostatic shock doesn't exist.
And the weapon propelling the needles is a rail gun. They've solved the problems, and have managed to make them in hand gun size.

[Sea Skimmer]

While there would obviously be a wide range of different rounds, assume for simplicity three standard types:
Pistol needle: muzzle velocity 1000m/s, mass 3g, length 50mm, max diameter 2mm

So that's a pistol 50% more powerful then a .44 magnum but its only going to make a 2mm wide hole in the person. This does not sound like a very effective weapon to me.

Rifle needle: velocity 3000m/s, mass 5g, length 75mm, max diameter 3mm

That would be several times the muzzle energy of .50cal BMG, which even if needlers have no powder recoil, which also means no possible muzzle break, is still going to be one hell of a human overpowering amount of recoil. The damage path inside the body will be limited by the extremely short contact length, it is hard to know but with the initial damage path so small the body has a lot of options for not bleeding to death.

Heavy needle (from their version of a heavy machine gun): velocity 5000m/s, mass 10g, max diameter 4mm

That's like 25mm autocannon level of firepower, you'd need a mount weighing at least several hundred pounds to support a weapon like that, let alone with automatic fire. At that point your probably going to want a much different weapon with a much heavier projectile so it actually has some velocity left several kilometers away.

Finally, another weapon is gaining popularity—it fires shotgun cartridge-sized hollow-charge rounds, which create a metal jet about 1mm in diameter.

The explosion of a shotgun sized explosive in contact with a person would just kill them outright, barring perhaps a hit on an out held hand or foot. The shock would do in the brain and the lungs. The jet damage would probably be like getting hit by a mix of buckshot sizes, it's not going to do anything too special because the mass of the warhead liner just has to be very low.

I'm not sure anyone would even bother with ammo like this if you could get a 3km/s rifle, even one firing a projectile with a more human realistic level of firepower. At 3km/s armor vs penetration becomes largely a matter of density, you could penetrate nearly anything to at least the length of the projectile. That would mean your rifle could do things like saw down an armored steel door.

My assumption is that if a needle penetrates armour, it would cause a spray of razor-sharp armour fragments, which would chew a much larger hole than the needle alone could.

If the armor is so dangerous then why is anyone using it?

[Jub]

problem with something like that is that the wire would negatively effect your accuracity in anything but extreme close range (read:melee range) remember that these needles aren't gonna be that big so having a set loose weights trailing behind them would effect the balance immensly (as even the wire would be similar weight to a signifigant portion of the weight of needle). Not mention it would create a another level of complexity to the projectile.

Bullets work because they're in the end really really simple.

I know it would significantly up complexity, but I've seen projectiles with tails fired before. The best example I can think of is the MI-Bullet (Multiple Impact Bullet). It comes in .45 ACP and 12 gauge sizes and it consists of a central bullet/slug and three trailing lines with a metal flechet hanging off the end. It's designed to allow for higher hit probability, but I could see the same idea applying to a flechette round.



The bullet manufacturere's homepage

[Purple]

Actually to an unarmoured human modern military bullets will simply drill a hole through the body because a)they're designed to defeat body armour and b) the Geneva Conventions say the bullet expanding, breaking apart or stuff like that is a big no-no.

Nope. The convention only banns expanding ammo which is why you only ever see that on police/civilian handgun rounds. But the worlds favorite assault rifle cartridges 7.62x39mm, 5.54x39mm and 5.56x45mm are designed to tumble, tumble and fragment respectively. These are all well known facts, I am surprised I have to argue them.

[LastShadow]

What are we talking about, size wise? Length? Min/Max diameters?

Are we talking larger needle point style, sewing need style? Halo Needler style? Im a little confused on your needle style.

Is it chemically propelled? Magnetically accelerated? Technobabbly accelerated?

Is the object maximum penetration? Maximum soft tissue damage?

All in all im looking at this like a nail gun with its safeties removed, it will make holes but not much else.

Now if it was firing darts that looked something like:
http://www.jebiga.com/wp-content/upload ... IFE-03.jpg
penetration and maximum soft tissue damage. In obviously a dart form instead of a sword.

[Jub]

What are we talking about, size wise? Length? Min/Max diameters?

Are we talking larger needle point style, sewing need style? Halo Needler style? Im a little confused on your needle style.

Is it chemically propelled? Magnetically accelerated? Technobabbly accelerated?

Is the object maximum penetration? Maximum soft tissue damage?

All in all im looking at this like a nail gun with its safeties removed, it will make holes but not much else.

Now if it was firing darts that looked something like:
http://www.jebiga.com/wp-content/upload ... IFE-03.jpg
penetration and maximum soft tissue damage. In obviously a dart form instead of a sword.

These are the needles he listed in the OP:

Pistol needle: muzzle velocity 1000m/s, mass 3g, length 50mm, max diameter 2mm
Rifle needle: velocity 3000m/s, mass 5g, length 75mm, max diameter 3mm
Heavy needle (from their version of a heavy machine gun): velocity 5000m/s, mass 10g, max diameter 4mm

[LastShadow]

What are we talking about, size wise? Length? Min/Max diameters?

Are we talking larger needle point style, sewing need style? Halo Needler style? Im a little confused on your needle style.

Is it chemically propelled? Magnetically accelerated? Technobabbly accelerated?

Is the object maximum penetration? Maximum soft tissue damage?

All in all im looking at this like a nail gun with its safeties removed, it will make holes but not much else.

Now if it was firing darts that looked something like:
http://www.jebiga.com/wp-content/upload ... IFE-03.jpg
penetration and maximum soft tissue damage. In obviously a dart form instead of a sword.

These are the needles he listed in the OP:

Pistol needle: muzzle velocity 1000m/s, mass 3g, length 50mm, max diameter 2mm
Rifle needle: velocity 3000m/s, mass 5g, length 75mm, max diameter 3mm
Heavy needle (from their version of a heavy machine gun): velocity 5000m/s, mass 10g, max diameter 4mm

I missed the measurements so thanks for pointing it out.

Those are super thin, i really cant envision them doing a whole lot of damage.

[Sky Captain]

One problem with such small needles is they would loose speed quickly in atmosphere. However in vacuum such ammo may make a lot of sense. If all that's needed to kill human soldier is to breach an armored spacesuit then maximum possible velocity to maintain accuracy over long distances and small size projectiles so soldiers can carry more of them would be very desirable properties.

[Korto]

These replies are very helpful, and seem to fit in well with what I wanted. I like the idea that the big bad armour-piercing weapon is kind of lacklustre when confronted with an unarmoured man, and Skimmer's doubt about the usefulness of the shaped charge weapon fits in well with what's happening. The only reason the weapon is becoming popular is because a new kind of EMP weapon is making itself known, which is capable of destroying the rail gun electronics even through its hardening. The shaped charge weapons have no electronics at all. It may be that they'll manage to improve the hardening of the rail guns in the future, in which case the shaped charges may lose popularity again.

Special note - they do make ammunition for unarmoured targets--lower velocity, more stopping power--but going into a fight, most decide to err on having ammunition that's poor against unarmoured targets, than completely useless against armoured ones.

To answer you, Skimmer, the reason they use that armour is that all other armour materials look like tinfoil next to it. Yes, it shatters when it fails, but it takes an awful lot to make it fail.
At least, that's what I was aiming for. If I've failed in that, ooops.

Can anyone have a guess at what the effective range of these weapons would be? Short is good. It's more dramatic.

In a story, the main guy said that a Heavy Needler could fire a needle (10g 5000m/s 4mm thick 1000mm long) through "one end of the mansion to the other", through multiple heavy masonry (brick) walls. Would he have been correct, or would the needle likely have exploded hitting the first wall? (It's all right for him to be wrong, he's a merchant/pilot/starship captain, not trained military.)

[Purple]

Shaped charges do have electronics in them. Sort of. The detonation of a shaped charge has to be precise lest the whole thing get crushed on impact before triggering properly. And to achieve that you have to use something called a piezoelectric fuse. And that's an electrical sensor. So any EMP is likely to mess those up as well. If you want to EMP proof your weaponry you pretty much have to go back to gunpowder firearms and 30's era chemical fuses.

[Gunhead]

Piezoelectric is not electronic in anyway in common HEAT warheads like say RPG-7 rounds. It's simply a method of generating a spark from impact. In short it is an impact fuse.

-Gunhead