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Author Topic: Ice Bullet question
Mouse
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I thought an ice dagger was supposed to be the undetectable weapon.

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"You see? The mysteries of the Universe are revealed when you break stuff." Coop from MegasXLR

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Sasquatch
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I bet the sawdust version would go a long ways to holding the ice bullet together, but the sawdust would leave it's own evidence. It might even be DNA matchable to the original board/tree.

Personally, I've always wanted to try a Cesium bullet, not only would it consume itself and leave no remnants, it would undoubtably increase the lethality of the wound.

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Unusual Elfin Lights
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I do have a bit of a background in ballistics. Couple this with Hero Mike's background in physics and I think we can have an answer.

One thing about increasing the amount of ice to increase the kinetic energy. Ballistics has shown that anytime the projectile length gets over 7 times the calibre, the projectile is ballistically unstable. So adding more water to a conventional chamber will not get the results desired.

How I would attempt this experiment is two fold:

- wadding: I would use some form of base wadding to act as a buffer between the combustion of the propellant in the chamber and the cold base of the bullet. This will, hopefully, reduce the amount of melting that will severely impact the bullet flight.

- sabot: modern tanks fire a round called APFSDS which stands for Armoured Piercing, Fin Stabilised, Discarding Sabot. This round has a 2.5 cm projectile that has a series of collars (sabots) around it. The sabots keep the projectile centred in the 10.5 cm barrel, they are the cause of obturation in the chamber, and once the projectile leaves the barrel, they fall away leaving only the projectile in ballistic flight. The charge used to propel this is the same as the charge for a 105 mm HESH round, but the muzzle velocities are greatly different. One advantage of the sabots is that they would be the ones absorbing the heat from the friction of the barrel, not the ice bullet.

For the experiment, I would use a larger calibre rifle, perhaps a .50 sniper variant. I would have a specially created round. This round would have the standard casing with propellant. In the projectile, I would have the base being a Teflon based “wadding” backed on the rear sabot. I would have a 7.62 mm ice projectile sitting in the sabots. I am a firm believer that 7.62 is needed to permanently stop a person. 5.56 is good, but not a guarantee. When fired, the Teflon wad would push the base of sabot pushing the rest of the projectile down the barrel. The spinning of the round would impart some stability in flight. Once the projectile has left the barrel, the wadding and sabots fall off and land within 50 metres. The bullet is able to fly for about 800 metres (my estimate based upon how the rifle shoots). Evidence at the target? Big hole. Evidence elsewhere? There will be some sabots and a piece of Teflon wad sitting near the sniper position.

The sound would still be quite loud, and the ability to hide a .50 is nearly impossible, especially skiing down a hill with Russians chasing you on snowmobiles…

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Ganzfeld
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I have a question about this that seems pertinant: How cold can powder be before it becomes useless? It seems you would want to have an ice bullet as cold as possible to limit the amount of vaporization or melting.
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Unusual Elfin Lights
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quote:
Originally posted by Ganzfeld:
I have a question about this that seems pertinant: How cold can powder be before it becomes useless? It seems you would want to have an ice bullet as cold as possible to limit the amount of vaporization or melting.

One problem with ice that is too cold is that it shatters when stress is placed upon it. Now whether an ice bullet would shatter anyways is up for conjecture, as its crystalline structure is not that strong.

For powder, though, are you talking the "gunpowder" or "powdered ice"?

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Troberg
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quote:
I would hope that an autopsy official would find the mercury.
I think we can assume they would find the bullet hole anyway. We must make a distinction between undetectable and untracable. As the effects of the hit will be plainly visible, we can pretty much forget undetectable, but we can achieve untracable.

On the other hand, if we just want to have an untraceable weapon, I'd go for an ordinary shotgun. As I understand it, shot gun pellets are not traceable. If I was an assassin, I'd sure prefer to use a proven technology rather than some experimental gamble.

quote:
Freeze water and sawdust, hard as concrete, experiments were done in GB and Canada to check the fesibility of building a huge floating airfield with it. History Channel
Not only airfields, and saw dust is not needed:

http://en.wikipedia.org/wiki/Ice_hotel

quote:
Most bullets are not aerodynamic. Indeed they are extremely non-aerodynamic. That is why they are generally fired from a rifled barrel. The rifling spins the bullet and gyroscopic forces keeps it from tumbling.
Hmm, this set my mind off on a tangent. Presumably, the most aerodynamic form is the shape of a water drop. I wonder how a bullet in that shape would work? It would have the center of gravity up front, with a tail to stabilize it, so it would probably be almost as stable in flight as a dart. The low drag would allow it to retain its energy longer, as well as giving it a flatter and longer trajectory. The lack of a pointed front would probably make it flatten on impact, but as it has the material in the tail working it's way forwards, the rear part of the bullet may provide some penetration, especially if made from a harder material.

Now, how to set up an experiment to test this, preferably surviving to see the results?

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/Troberg

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Hero_Mike
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Taking into account some of the things that Yoo-ee-ell and MaxGunnar have said, it seems unlikely that a bullet can be made entirely of ice, without adding some other material (which is potentially tracable), or using a fancier "sabot" round which also suggests the use of a larger calibre weapon.

The best bet - and it still seems far-fetched - is a large calibre handgun (say 9mm) with a highly modified bullet - perhaps made from dry ice or a water/sawdust mixture. (The best way to avoid the tracability of the sawdust is to use sawdust from an engineered wood product - like plywood or MDF, which are commonly found and not made from only one distinct tree.) The charge and bullet shape will be optimized for enough short-range stopping power to be lethal, probably at the expense of any kind of range or accuracy - though handgun accuracy beyond even a few dozen yards is limited. You'll also have to keep the bullets cold - *very cold* - and while this may not affect the powder charge, it will also affect the dimensions of the metal casing. At sufficiently cold temperatures the casing will have shrunk enough to affect its fit in the firing chamber. Such a bullet, at higher temperatures, would be oversized.

Almost as important as the bullet itself would be a means of carrying them while frozen - a small "cooler" chilled by a sleeve of, say, liquid nitrogen, would keep everything frosty until the last minute, when you load your gun and "ice" your enemy.

The sublimating gas from a "dry ice" bullet would not be enough to force it out of the gun. If you hold a piece of dry ice in your hand, it does not leap away from it. The gas escape would be constrained, as is the bullet. A potential problem would be having your typical automatic pistol with the bullets in a magazine inside the grip - holding the gun for a long time will melt the bullets, and any melting will change the dimensions of the bullet - which is bad news. See above for solutions to this problem.

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Unusual Elfin Lights
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quote:
Originally posted by Troberg:
quote:
Most bullets are not aerodynamic. Indeed they are extremely non-aerodynamic. That is why they are generally fired from a rifled barrel. The rifling spins the bullet and gyroscopic forces keeps it from tumbling.
Hmm, this set my mind off on a tangent. Presumably, the most aerodynamic form is the shape of a water drop. I wonder how a bullet in that shape would work? It would have the center of gravity up front, with a tail to stabilize it, so it would probably be almost as stable in flight as a dart. The low drag would allow it to retain its energy longer, as well as giving it a flatter and longer trajectory. The lack of a pointed front would probably make it flatten on impact, but as it has the material in the tail working it's way forwards, the rear part of the bullet may provide some penetration, especially if made from a harder material.
The challenge of this type of form for a bullet is getting the maximum push during acceleration. The reason for the flat back of the bullet is that it can receive maximum force to push it up the barrel. If it has a tear shaped back some of the force will be spent compressing the bullet.
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DemonWolf
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quote:
Originally posted by Yoo-ee-ell:
quote:
Originally posted by Troberg:
quote:
Most bullets are not aerodynamic. Indeed they are extremely non-aerodynamic. That is why they are generally fired from a rifled barrel. The rifling spins the bullet and gyroscopic forces keeps it from tumbling.
Hmm, this set my mind off on a tangent. Presumably, the most aerodynamic form is the shape of a water drop. I wonder how a bullet in that shape would work? It would have the center of gravity up front, with a tail to stabilize it, so it would probably be almost as stable in flight as a dart. The low drag would allow it to retain its energy longer, as well as giving it a flatter and longer trajectory. The lack of a pointed front would probably make it flatten on impact, but as it has the material in the tail working it's way forwards, the rear part of the bullet may provide some penetration, especially if made from a harder material.
The challenge of this type of form for a bullet is getting the maximum push during acceleration. The reason for the flat back of the bullet is that it can receive maximum force to push it up the barrel. If it has a tear shaped back some of the force will be spent compressing the bullet.
Not if we use a flat backed sabot.

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Troberg
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quote:
Not if we use a flat backed sabot.
Or just add some extra propellant.

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/Troberg

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DemonWolf
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quote:
Originally posted by Troberg:
quote:
Not if we use a flat backed sabot.
Or just add some extra propellant.
But if we add the extra propellant the force will still bend around the readward facing tip of the ice drop. The sabot will make the force push the drop much more effectively.

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Ganzfeld
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quote:
Originally posted by Yoo-ee-ell:
For powder, though, are you talking the "gunpowder" or "powdered ice"?

I was assuming you'd want to have the bullet very cold and the gunpowder would, without sufficient insulation, also be cold. So I thought that would be one limitation.

True that you would rather have more elasticity in your ice but that would also allow the ice to vaporize easier, no?

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Arts Myth
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On the subject of untraceability, how about a bullet made of bone? Since any sort of untraceable bullet would be likely used in black-ops type assassinations, the shooter would presumably be a pro, so they'd only have to be sure that the shot hits bone. The resultant fragments would camouflage the remains of the bullet, which would be designed to shatter upon impact with the bone.

Why does this bring to mind those tooth-firing guns from Existenz..?

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jimmy101
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For Troberg: Rain drops are not shaped like they are typically drawn, i.e., with a "tear-drop" shape. According to wiki they are either spherical or spheroids with a flat leading edge, it depends on how big the drop is. Furthermore, raindrops move pretty slow. The terminal velocity is usually in the range of 5~30 fps which is pretty slow. (A baseball's terminal velocity is about 100 fps.) So would a rain-drop shape work well at "bullet" like velocities?

For Yoo-ee-ell:
quote:
The challenge of this type of form for a bullet is getting the maximum push during acceleration. The reason for the flat back of the bullet is that it can receive maximum force to push it up the barrel. If it has a tear shaped back some of the force will be spent compressing the bullet.
I don't think the challenge is getting the maximum push during acceleration. The challenge is getting the maximum push the hunk of ice can handle, which is different constraint. Too much push and the round will disintegrate.

Can you provide a cite for the affects of the rounds butt shape? I would think the flat butt is just because of two things; (1) the shape of the butt doesn't make much difference (in the barrel anyway) and (2) a flat butt is easiest to make.

The force on the backend of a round is only a function of the area, not the shape. Given the amount of energy that is expended accelerating the round (and expanding the barrel) I would think the small amount of energy lost to compressing a pointed butt would be unmeasurable. The shape of the butt will affect air drag but that is a different matter. Besides, in this imaginary gun there is more than adequate power. Any standard modern round (even a .22) has sufficient energy to kill. Granted, not from skis at a range of a thousand meters but range is nowhere mentioned in the statement of the problem.

I think Yoo-ee-ell has several good ideas though. Clearly to get to the mass that Hero thinks is needed you would want a large caliber. Furthermore, a 0.22 "saturday night special" is still considered to be a lethal weapon (wouldn't bet my life on it one way or the other but it fits the statment of the problem.) To get to the mass that Hero thinks is needed we just need to get the slug of ice to have the mass of a 0.22 round (I know, very wimpy, no range, very minimal stopping power but again it fits the statement of the problem).

Lets say a 0.45 barrel, twice the diameter of the 0.22 and with 4x the area. Hero would like ~13x the volume in the ice as in the lead round to get the same total mass. We get 4x from the bigger barrel so we need the ice chunk to be about 3x longer than a 0.22 to get the same total mass. A 0.22 is what, 1/2" long? So we have an ~1.5" long ice slug of 0.45 caliber to get about the same mass as a 0.22 round. (Yes I know, a 0.22 sucks, but the ATF considers it a lethal firearm so it fits the statement of the problem.) Yoo-ee-ell would like the length to be no more than the 7x the caliber for stability. Not sure that stability really matters, the statment of the problem does not say this has to work at 1000', of even 100', it could be point blank where aerodynamics have little affect. Nonetheless, 1.5" x 0.45" is well within the 7:1 ratio needed.

Total Power: The problem does not appear to be power limited. You can always use more powder. Besides pretty much any standard round has enough power in the powder for a lethal round at short range. Too much power is probably more of a problem, if the rounds turns into a puff of snow it is not going to be very effective. Related to the total available power is how fast the power is released and how long the round can extract power from the charge. Again, given the constraint that the round has to hold together. So, it would seem that it might help to use a slow burning powder (like black powder or Pyrodex) and a long barrel.

Yoo's suggestion of wadding is probably a good idea. Even several layers of cloth will provide some protection to the ice. A greese saturated fabric, as used in muzzle loaders, may be even better. The wadding from a muzzle loader survives firing more or less intact with only minimal burning. Suggesting that waddingmay provide some protection to the ice. Yoo's also suggested a sabot which is also a possibilty but may require more work.

Construction of the round: If I was doing this I would freeze the round in situ. Load the weapon with a suitable blank round, perhaps add a little wax over the top of the blank for additional protection from the water. Add wading and/or sabot. Point the muzzle up and add sufficent water. Freeze the entire gun muzzle up. Guns and powder are not bothered much by sub-zero temperatures. Having the gun at say 20F when fired is not a problem.

You now have a weapon loaded with a round with the same mass as a 0.22. The round is considerably larger than a 0.22 so it will not have much range.

The biggest potential problem is the danger inherant in firing a weapon with a "round" literally frozen in the barrel.

I can't think of any reason why that wouldn't work. You may need to fine tune the powder charge (and perhaps use an even slower burning powder).

You are not going to have a weapon that is affective at 1000' but it should be adequate at short range.

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Hero_Mike
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quote:
Originally posted by jimmy101:
Furthermore, a 0.22 "saturday night special" is still considered to be a lethal weapon (wouldn't bet my life on it one way or the other but it fits the statment of the problem.) To get to the mass that Hero thinks is needed we just need to get the slug of ice to have the mass of a 0.22 round (I know, very wimpy, no range, very minimal stopping power but again it fits the statement of the problem).

The most common way that a 22-calibre pistol is used as a lethal weapon is with a single shot, at close range, to the base of the skull of an already subdued opponent. It isn't a particularly "deadly" weapon in most other circumstances. Several episodes of CSI (and my own common sense) have taught me that the .22 bullet penetrates the skull but does not come out, bouncing around inside and creating all kinds of havoc. But a single shot from a .22 even from, say, 20 feet, is not likely to be lethal unless it hits a very sensitive "soft" area.

For any meaningful analysis of an "ice bullet" with "lethal" capabilities, it has to be at least as deadly as, say, a typical .38 "police special" revolver - the standard law enforcement sidearm for many years. Otherwise this expands exponentially to the point where an ice bullet is as "lethal" as an air gun pellet.

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Aptenodytes_Forsteriis
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I have to take a bit of issue with the assumption that the mass of the ice is the determining factor. Most studies of handgun wounds have concluded that the wound cavity, or tube of destroyed flesh is the crucial factor. A handgun round kills by destroying tissue, not by imparting energy to the target. So all we would need to do is to get the ice up to a velocity sufficient, given the shape of the ice projectile, to penetrate deep enough to strike a vital organ, heart, liver, lungs etc. A dart shape might well be the way to go.

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Troberg
Angels Wii Have Heard on High


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quote:
For Troberg: Rain drops are not shaped like they are typically drawn, i.e., with a "tear-drop" shape. According to wiki they are either spherical or spheroids with a flat leading edge, it depends on how big the drop is. Furthermore, raindrops move pretty slow. The terminal velocity is usually in the range of 5~30 fps which is pretty slow. (A baseball's terminal velocity is about 100 fps.) So would a rain-drop shape work well at "bullet" like velocities?
Yep, I know, I used the term loosely. Still, the drop shape (as it is commonly drawn) is still the most aerodynamic. That's why you see it in aircraft wings, aircraft bodies, ship hulls, rotor blades and so on.

The faster you want to go, the more elongated you have to make it, but that's managable. This is, by the way, the same reason that the maximum speed of a ship with a deplacement hull (ie non planing) is basically a function of it's length (actually, it's a combination of length and wave length of the medium you travel in). Of course, other factors also weigh in, but length is very important.

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/Troberg

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me, no really
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My first (mostly uneducated) thought is that the teardrop bullet idea would need the sabot idea, not necessarily due to efficiency of the explosion pushing it out, but to combat any turbulence effects in the expanding gases. I could easily see any slight imbalance in the forces slapping that tail sideways, and affecting the accuracy of the round. A sabot arrngement would at least get it out into the open pointing in the right direction.

me

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Troberg
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quote:
My first (mostly uneducated) thought is that the teardrop bullet idea would need the sabot idea, not necessarily due to efficiency of the explosion pushing it out, but to combat any turbulence effects in the expanding gases. I could easily see any slight imbalance in the forces slapping that tail sideways, and affecting the accuracy of the round. A sabot arrngement would at least get it out into the open pointing in the right direction.
Makes sense.

Now, how to set up a test?

The best I can figure out (if I want to do it safely) is to buy drop shaped lead sinks, the kind used in fishing. Cut off the eye. Find a pipe of apropriate inner diameter, hook it up to a pressure tank through a quick release valve and use my compressor to generate the pressure. Sabots can be made by mixing polyeuretan glue with water, which will bubble up to a fairly hard plug. Should be fairly easy, but I need some place to try the contraption.

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/Troberg

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Mycroft
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The tear-drop shape is caused by much more friction than given by air resistance, ie rain in window. A picture of an acualy terminal velocity raindrop would be almost completely sperical due to surface tension.
Back to the OP you don't need an ice bullet to cause the damage; If you have ever seen a film of bomb disposal robots blowing holes in car locks, what they are using is WATER!! Of course this would only work at close range and would leave other forensic traces, but at least you couldn't identify the gun by the bullet. I have also seen a tallow (animal fat) candle used to shoot through an inch of wood.

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jimmy101
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quote:
Originally posted by Mycroft:
The tear-drop shape is caused by much more friction than given by air resistance, ie rain in window. A picture of an acualy terminal velocity raindrop would be almost completely sperical due to surface tension.
Back to the OP you don't need an ice bullet to cause the damage; If you have ever seen a film of bomb disposal robots blowing holes in car locks, what they are using is WATER!! Of course this would only work at close range and would leave other forensic traces, but at least you couldn't identify the gun by the bullet. I have also seen a tallow (animal fat) candle used to shoot through an inch of wood.

According to Wiki a terminal velocity raindrop is only approximately spherical when the drop is pretty small. Larger raindrops are nowhere near spherical. The frictional force from the air flow is significant, indeed it is "1G" of force, more than enough to distort the shape of a sphere of liquid.

As to your second suggestion, it would work indeed. The standard hydraulic pumps used in tractors and such generate enough force to inject hydraulic fluid into a person. A small leak in a hydraulic line is very dangerous to anybody nearby. Heck, you can buy metal cutting "squirt guns". Of course, they aren't exactly portable. (This metal fabricator has a waterjet cutter that'll cut through 6" of metal.)

For Troberg: Here is a simple design for firing your round. Should be able to launch a lead sinker at many hundreds of feet per second. Here's a picture of another design. Both are made with stuff you can get at the local hardware store. (I've made a version of the first one except it is a muzzle, instead of breach, loader. It'll put a 1" diameter by 2" long piece of hardwood dowel through 1/2" thick plywood.)

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Jason Threadslayer
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quote:
Originally posted by Gerard Morvan:
So, what's your opinion on this subject?

Use something that dissolves in the body, like sutures.

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Troberg
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quote:
Use something that dissolves in the body, like sutures.
How long do you plan to hide the body before the police get a chance to examine it?

quote:
For Troberg: Here is a simple design for firing your round.
There's no way I'll launch an experimental round from a hand held launch platform, especially since there are so so many joints that are all potential failure points if the round should jam in the barrel. I was thinking of using something like an old fire extinguisher as pressure vessel, pressurize it with a compressor, then use a valve assembly much like the construction you found and a barrel directly on that. Less things that can go wrong.

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/Troberg

Posts: 4360 | From: Borlänge, Sweden | Registered: Nov 2005  |  IP: Logged | Report this post to a moderator
Rivkah Chaya
I Saw Three Shipments


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It also depends on what you want to accomplish. You could cause some serious wounds with an air gun and ice bullet, but doubtfully kill someone. For a single bullet to kill almost on impact, it has to enter the heart or brain, and to do that it has to penetrate the ribcage or skull while remaining relatively intact. I doubt an ice bullet has that kind of density.

Bullets that enter major arteries can cause a person to bleed to death pretty quickly, but you have to be very lucky to hit one in a single shot. People who bleed to death from gunshots usually have more than one wound, and since you're unlikely to break a bone with an ice bullet, your victim is unlikely to stay in range for you to reload to get a second shot

Modern bullets usually kill because of the way they are engineered-- bullets used in warfare for example, can cause massive tissue damage. I don't think you could engineer an ice bullet to be like a "cop-killer" bullet.

Simple projectile bullets like musket balls usually caused wounds that became infected and couldn't be treated back in the days when people used muskets. Something like half the people who died of musket wounds either died of infection, or bled to death on a battlefield after being left to bleed for several hours, partly because this was before medics, and partly because the prognosis was so poor, some people thought it was kinder to let people bleed to death.

Most musket wounds would actually be treatable with modern medicine.

So yes, you could HURT someone with an ice bullet and an air gun, but probably not kill them.

If your goal is to have an untraceable bullet, as opposed to a mysterious wound a la CSI, use an exploding bullet, and just to be safe, file the inside of your gun barrel afterward.

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Troberg
Angels Wii Have Heard on High


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quote:
If your goal is to have an untraceable bullet, as opposed to a mysterious wound a la CSI, use an exploding bullet, and just to be safe, file the inside of your gun barrel afterward.
Or a shotgun.

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/Troberg

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jimmy101
The First USA Noel


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quote:
Originally posted by Troberg:
There's no way I'll launch an experimental round from a hand held launch platform, especially since there are so so many joints that are all potential failure points if the round should jam in the barrel. I was thinking of using something like an old fire extinguisher as pressure vessel, pressurize it with a compressor, then use a valve assembly much like the construction you found and a barrel directly on that. Less things that can go wrong.

Jamming of a round in the barrel is really no different than not opening the main valve. Only one more joint is subjected to pressure. In a combustion weapon a jammed round can be very bad, in a compressed air weapon it is not a big deal.

Pressure rated PVC pipe is rated to more than 200 PSI for diameters less than an inch or so. These guns are typically operated at 100-125 PSI, the maximum pressure you can get from a standard shop compressor.

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beaver_slayer
Deck the Malls


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Let's put it this way: the density of ice is roughly 1/10 of a steel. The peneteration will obviously be inferior
Posts: 246 | From: Toronto, ON / Kyiv, Ukraine | Registered: Jul 2005  |  IP: Logged | Report this post to a moderator
me, no really
We Wish You a Merry Giftmas


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Now this could work. Guessing it may not be easily portable though. It could give you decent velocity though. I have watched a Mach 25 wind tunnel in use a few times. Essentially, it is a long tube. You seal it at one end with a steel plate with a dimple in the centre. You then use a compressor to pressurise behind the plate, until there is enough pressure there to blow out the plate, and viola, a slug of high pressure air proceeds down your tube. You need a pretty high pressure compressor though. I don't know if the air pressure by itself would be fatal, but it could push a projectile of some sort. Again though, we are getting away from the opening problem of shooting from a normal gun and having the round impossible to identify to forensics.

me

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Troberg
Angels Wii Have Heard on High


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quote:
Jamming of a round in the barrel is really no different than not opening the main valve. Only one more joint is subjected to pressure. In a combustion weapon a jammed round can be very bad, in a compressed air weapon it is not a big deal.
Excellent point. I must have turned my brain off completely for a while there and let my respect for compressed air (it's one of the most dangerous tools in a shop) get the better of me.

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/Troberg

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Jason Threadslayer
Let There Be PCs on Earth


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quote:
Originally posted by Troberg:
quote:
Use something that dissolves in the body, like sutures.
How long do you plan to hide the body before the police get a chance to examine it?
No need to hide a body if the body is alive for a few days (see Georgi Markov).

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All posts foretold by Nostradamus.

Turing test failures: 6

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Troberg
Angels Wii Have Heard on High


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quote:
No need to hide a body if the body is alive for a few days (see Georgi Markov).
Sure, but then we are back at the problem of simple solutions being available. In this case, the "bullet" was fired with the muzzle touching the victim, and if you are that close and intend to use some toxin (as was the case), it's easier to scrap the bullet and just use pressure to inject the toxin. No carrier is needed, just spray it straight in from a tiny nozzle.

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/Troberg

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BoKu
Happy Xmas (Warranty Is Over)


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quote:
Originally posted by jimmy101:
Most bullets are not aerodynamic...

The only "aerodynamic" standard bullet shape I know of is a round ball.

I offer as counter-demonstration the ogive-nosed and boat-tailed shape of the standard bullet of the .50 caliber Browning machine gun. This round was known to be reliably stable at speeds exceeding Mach 1, so when they were designing the X-1 research airplane (think "Glamorous Glennis") they patterned the fuselage on it. I once chatted with the guy who lofted the X-1 fuselage for Bell - I think it might have been Howie Burr - and he confirmed that a conscious decision was made to emulate the shape of the bullet.
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jimmy101
The First USA Noel


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quote:
Originally posted by BoKu:
quote:
Originally posted by jimmy101:
Most bullets are not aerodynamic...

The only "aerodynamic" standard bullet shape I know of is a round ball.

I offer as counter-demonstration the ogive-nosed and boat-tailed shape of the standard bullet of the .50 caliber Browning machine gun. This round was known to be reliably stable at speeds exceeding Mach 1, so when they were designing the X-1 research airplane (think "Glamorous Glennis") they patterned the fuselage on it. I once chatted with the guy who lofted the X-1 fuselage for Bell - I think it might have been Howie Burr - and he confirmed that a conscious decision was made to emulate the shape of the bullet.
It depends on what is meant by "aerodynamic". If it means low drag then yes, there are many shapes that have low drag.

If it means the shell is stable in flight then no, a 0.50 caliber round is not stable in flight. That is why it is fired from a rifled barrel. The spinning of the round is what makes it stable, the round itself is "aerodynamically unstable" and will tumble if not spun about its axis of flight.

There are a few aerodynamically stable rounds such as self propelled grenades and rockets. The M1A1 Abrams main gun is unrifled and fires a fin-stabilized, aerodynamically stable, round.

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DemonWolf
Ding Dong! Merrily on High Definition TV


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On CSI right now, Grissolm is firing a frozen meat bullet.

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Friends are like skittles: they come in many colors, and some are fruity!

IMJW-052804

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Astra
The "Was on Sale" Song


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quote:
Originally posted by DemonWolf:
On CSI right now, Grissolm is firing a frozen meat bullet.

Oh god. Here come the fan girls.

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This has been yet another... USELESS POST.

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