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Post by OziRiS on Jun 26, 2013 9:45:08 GMT
However the lethality of a projectile is based not just on its speed, but also on its mass. Lower the mass - say by using ice instead of metal - and you have to increase velocity significantly to compensate. (And this doesn't account for what happens when the projectile hits something.) In the case of an ice bullet you'd need to increase the speed by a factor of three or four - which would mean a muzzle velocity at least a third higher than modern high-powered rifles. The only conventional weapons we have that produce velocities in that range are classified as artillery and usually attached to an engine. Even though privatepatty suggests that frozen blood cells have nothing to do with an "ice" bullet as such, I still like it as an evolution on the original idea, as in: We've established that frozen water doesn't work, but the need to make the projectile "disappear" after impact to conceal evidence is still there. What to do now? If what you're saying here is true (which I'm assuming it is, since you're usually pretty good at getting your facts straight) and what Hodgins said in the episode of Bones I'm referring to is also true - that blood is 3 times as dense as water - then that could get us past the velocity problem and might actually make the blood bullet feasible as a projectile. |
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Post by Cybermortis on Jun 26, 2013 13:18:48 GMT
A Bullet is any solid projectile used in personal or man-portable ranged weapon that isn't a bow - the projectile fired from a sling or slingshot is also called a bullet. Artillery use shell or shot not bullets.
The size at which you go from firearm to artillery is, and always has been rather grey. These days anything over 13mm is usually considered to enter the artillery/cannon range (for Americans who don't know their metric system 0.5 inches is 12.7mm). In practice you rarely see cannon smaller than 20mm as they are too weak to act as anti-armour/artillery and far too large and heavy to be practical use by the 'Grunts'. Imagine a mini-gun or heavy machine gun, then double the weight of the gun and its ammunition and the recoil and you'll quickly understand one of the major reasons weapons of these calibres are simply not in use.
We can't ignore the basis for the myth - which is that an ice bullet is an assassins tool. You could rig up an air cannon that would be capable of killing someone, but a 40 foot long barrel is not exactly something covert. Likewise the use of a sabot leaves evidence behind, which is what using an ice bullet is meant to avoid. Or as OziRiS said above;
Of course as I and others have pointed out on Discovery, investigators don't need to find a bullet to know someone has been murdered or to track them down arrest and have them convicted. In fact it is common to either never find a bullet or to find one that is so badly damaged it is of little or no use for ballistics testing/comparisons.
Ice has a density of 0.9g/cm3, lead 11.34g/cm3 and iron 7.87g/cm3. So assuming the same muzzle velocity of 1000fps/305mps (the upper end of air rifles as noted earlier) and a one centimetre cubed 'bullet' we can plug the figures in to the formula Energy(Joules)=0.5xMass(kg)xVelocity2(mps) {This this case V=93,025}
Ice; 41.86 Joules
Lead; 527,452 Joules
Iron; 366,054 Joules
Someone, who understands maths FAR better than I do at this point can no doubt use these figures to work out how fast you'd have to propel ice so it had comparable energy to lead or iron. (If you do please show your calculations so I can hopefully understand it.)
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Post by privatepaddy on Jun 26, 2013 13:34:22 GMT
However the lethality of a projectile is based not just on its speed, but also on its mass. Lower the mass - say by using ice instead of metal - and you have to increase velocity significantly to compensate. (And this doesn't account for what happens when the projectile hits something.) In the case of an ice bullet you'd need to increase the speed by a factor of three or four - which would mean a muzzle velocity at least a third higher than modern high-powered rifles. The only conventional weapons we have that produce velocities in that range are classified as artillery and usually attached to an engine. Even though privatepatty suggests that frozen blood cells have nothing to do with an "ice" bullet as such, I still like it as an evolution on the original idea, as in: We've established that frozen water doesn't work, but the need to make the projectile "disappear" after impact to conceal evidence is still there. What to do now? If what you're saying here is true (which I'm assuming it is, since you're usually pretty good at getting your facts straight) and what Hodgins said in the episode of Bones I'm referring to is also true - that blood is 3 times as dense as water - then that could get us past the velocity problem and might actually make the blood bullet feasible as a projectile. "privatepatty" ? interesting well as long as you don't call me late for dinner alls good  |
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Post by the light works on Jun 26, 2013 14:04:07 GMT
of course, the fact that the victim suddenly fell down and started bleeding out through a hole that was not previously there is usually sufficient evidence to assume the death was not from natural causes... there are lots of more effective ways to defeat ballistics testing.
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Post by OziRiS on Jun 26, 2013 22:00:34 GMT
"privatepatty" ? interesting well as long as you don't call me late for dinner alls good Oops... Sorry  |
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Post by OziRiS on Jun 26, 2013 22:01:59 GMT
of course, the fact that the victim suddenly fell down and started bleeding out through a hole that was not previously there is usually sufficient evidence to assume the death was not from natural causes... there are lots of more effective ways to defeat ballistics testing. Well, we're not debating if there are better ways (which I fully agree with you that there are). We're debating if THIS way could possibly work. |
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Post by silverdragon on Jun 27, 2013 5:46:24 GMT
Density..... quick question, how about a super-saturated salt water solution frozen up... would that affect anything?... Saline would melt off with little to no traceable evidence.
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Post by Cybermortis on Jun 27, 2013 13:34:21 GMT
Density..... quick question, how about a super-saturated salt water solution frozen up... would that affect anything?... Saline would melt off with little to no traceable evidence. At zero degrees Celsius and the highest salt concentration possible you'd get a density of 1.000161g/cm3. Slightly higher than fresh water, but not so much that you'd see any significant improvement. |
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Post by User Unavailable on Jun 27, 2013 13:54:22 GMT
Density..... quick question, how about a super-saturated salt water solution frozen up... would that affect anything?... Saline would melt off with little to no traceable evidence. At zero degrees Celsius and the highest salt concentration possible you'd get a density of 1.000161g/cm3. Slightly higher than fresh water, but not so much that you'd see any significant improvement. Yep, and you still have the problem of not enough weight to penetrate to any depth, even if you could come up with a solution that would hold together at typical firing velocities. Lead birdshot fired at 1450 fps, the pellets don't penetrate humans well. Why, because they are not heavy enough and so don't have the energy and lose energy rapidly after firing. Other stresses to consider on a ice bullet, the breaking of the sound barrier. Enormous stresses that a metal bullet typically handles well The biggest threat to a ice bullet of course, is temperature and time. Once the bullet is pulled from its container and loaded in the weapon, it is melting. It has to be fired NOW. There can be no, dilly dallying around through a crowd, waiting for a clear shot, or waiting for just the right moment. It has to be fired NOW. |
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Post by Cybermortis on Jun 27, 2013 15:18:09 GMT
At zero degrees Celsius and the highest salt concentration possible you'd get a density of 1.000161g/cm3. Slightly higher than fresh water, but not so much that you'd see any significant improvement. Yep, and you still have the problem of not enough weight to penetrate to any depth, even if you could come up with a solution that would hold together at typical firing velocities. Lead birdshot fired at 1450 fps, the pellets don't penetrate humans well. Why, because they are not heavy enough and so don't have the energy and lose energy rapidly after firing. Other stresses to consider on a ice bullet, the breaking of the sound barrier. Enormous stresses that a metal bullet typically handles well The biggest threat to a ice bullet of course, is temperature and time. Once the bullet is pulled from its container and loaded in the weapon, it is melting. It has to be fired NOW. There can be no, dilly dallying around through a crowd, waiting for a clear shot, or waiting for just the right moment. It has to be fired NOW. As I said above someone with much better maths skills than I would have to do the calculations based on my figures above. But an estimate would be that you'd need a minimum muzzle velocity in the 4000-5000 fps range* to get a lethal amount of energy from an ice bullet**. These kinds of velocities are only seen in artillery pieces with rifles topping out at around 2000 fps. At these kinds of velocity no ice bullet is going to exit the barrel in a single piece even if you find a way to avoid it melting in the barrel. (*This is based on the density of Marble (2.6g/cm3 at the lower end). Marble was used for round shot prior to the introduction of iron shot, and stone was used in muskets before lead became commonly used.) (**Consider that iron shot has 8745 times the amount of energy as ice at a given velocity.) |
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Post by chriso on Apr 1, 2014 6:43:53 GMT
I can run the calculations, though I don't have the knowledge to tell you when the ice bullet will experience existential failure. You already have the calculations half done, though you made the error of forgetting to convert grams to kilos. The lead bullets energy, in your calculation, could run a 100 watt light for 87 minutes if converted directly to electricity. Interestingly, despite this the velocity you would of gotten would of been right either way. Essentially the ratio between the masses was all that mattered. Base energy calculated using lead at 305 mps, and .01134 kilograms of lead. Energy=.5Mass(kilo)*Velocity(mps)^2 Energy= .5*(.01134)*(305)^2 Energy=527.45175 Thats more like it. Base energy of 527.452. To get the equivalent velocity of an ice bullet, you set 527.452 to "Energy" and solve. Mass of ice bullet is .0009 kg, V stands for velocity: Done numerically: Energy=.5Mass(kilo)*Velocity(mps)^2 527.452=.5*(.0009)V^2 (2*527.452)=(.0009)V^2 (2*527.452)=(.0009)V^2 (2*527.452)/.0009=V^2 sqrt((2*527.452)/.0009)=V sqrt((1054.904)/.0009)=V sqrt(1172115.556)=V 1082.6428=V So around 1083 mps for an ice bullet of equivalent energy. That's around 3556 fps. For comparison, the speed of sound at sea level is around 340 mps. The ice bullet would be traveling around Mach 3.1 you were just a bit shy on your speed estimate, but pretty dang close. I am not going to bother writing the iron calculation out, but that would work out to be around 366.12 mps. If you want to test what you have learned you can see if you get the same number. A Bullet is any solid projectile used in personal or man-portable ranged weapon that isn't a bow - the projectile fired from a sling or slingshot is also called a bullet. Artillery use shell or shot not bullets. The size at which you go from firearm to artillery is, and always has been rather grey. These days anything over 13mm is usually considered to enter the artillery/cannon range (for Americans who don't know their metric system 0.5 inches is 12.7mm). In practice you rarely see cannon smaller than 20mm as they are too weak to act as anti-armour/artillery and far too large and heavy to be practical use by the 'Grunts'. Imagine a mini-gun or heavy machine gun, then double the weight of the gun and its ammunition and the recoil and you'll quickly understand one of the major reasons weapons of these calibres are simply not in use. We can't ignore the basis for the myth - which is that an ice bullet is an assassins tool. You could rig up an air cannon that would be capable of killing someone, but a 40 foot long barrel is not exactly something covert. Likewise the use of a sabot leaves evidence behind, which is what using an ice bullet is meant to avoid. Or as OziRiS said above; Of course as I and others have pointed out on Discovery, investigators don't need to find a bullet to know someone has been murdered or to track them down arrest and have them convicted. In fact it is common to either never find a bullet or to find one that is so badly damaged it is of little or no use for ballistics testing/comparisons. Ice has a density of 0.9g/cm3, lead 11.34g/cm3 and iron 7.87g/cm3. So assuming the same muzzle velocity of 1000fps/305mps (the upper end of air rifles as noted earlier) and a one centimetre cubed 'bullet' we can plug the figures in to the formula Energy(Joules)=527.452=0.5*(.0009)*V^2 {This this case V=93,025} Ice; 41.86 Joules Lead; 527,452 Joules Iron; 366,054 Joules Someone, who understands maths FAR better than I do at this point can no doubt use these figures to work out how fast you'd have to propel ice so it had comparable energy to lead or iron. (If you do please show your calculations so I can hopefully understand it.) |
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Post by the light works on Apr 2, 2014 2:04:50 GMT
so - now that they have delivered a mach 1 ping pong ball - what about using the same tech to launch the ice bullet?
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Post by chriso on Apr 2, 2014 6:30:25 GMT
I have not seen that episode, but I doubt it. Ice isn't the most coherent material, and if it breaks apart then air resistance, and thus heating, would increase exponentially. Not counting a vacuum chamber, which would invalidate the concept, I would expect that if the bullet made it to the end of the barrel, it would only go a few meters before vaporizing. Not exactly ideal for a covert assacination.
What about looking at it from another perspective? All sorts of nasty poisons can be frozen, what if you made a tiny ice bullet and gave it just enough power to pierce the skin? If it is slow enough to remain intact, the question is if A: it will still break the skin and B: if the fumes from the vaporizing ice would kill the shooter too.
I would imagine something along the lines of someone in the crowd with a specially modified cane or umbrella. Hopefully you could make a small enough pinprick that the security doesn't realize something serious is going on until too late.
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Post by the light works on Apr 2, 2014 14:32:46 GMT
I have not seen that episode, but I doubt it. Ice isn't the most coherent material, and if it breaks apart then air resistance, and thus heating, would increase exponentially. Not counting a vacuum chamber, which would invalidate the concept, I would expect that if the bullet made it to the end of the barrel, it would only go a few meters before vaporizing. Not exactly ideal for a covert assacination. What about looking at it from another perspective? All sorts of nasty poisons can be frozen, what if you made a tiny ice bullet and gave it just enough power to pierce the skin? If it is slow enough to remain intact, the question is if A: it will still break the skin and B: if the fumes from the vaporizing ice would kill the shooter too. I would imagine something along the lines of someone in the crowd with a specially modified cane or umbrella. Hopefully you could make a small enough pinprick that the security doesn't realize something serious is going on until too late. in the cold war era, a Russian official was poisoned by the injection of a pellet of a toxic material (I forget exactly what) by means of an umbrella gun - at the time of the injection he had complained about a person accidentally jabbing him with an umbrella (on a crowded sidewalk) |
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Post by ironhold on Apr 2, 2014 14:54:46 GMT
I have not seen that episode, but I doubt it. Ice isn't the most coherent material, and if it breaks apart then air resistance, and thus heating, would increase exponentially. Not counting a vacuum chamber, which would invalidate the concept, I would expect that if the bullet made it to the end of the barrel, it would only go a few meters before vaporizing. Not exactly ideal for a covert assacination. What about looking at it from another perspective? All sorts of nasty poisons can be frozen, what if you made a tiny ice bullet and gave it just enough power to pierce the skin? If it is slow enough to remain intact, the question is if A: it will still break the skin and B: if the fumes from the vaporizing ice would kill the shooter too. I would imagine something along the lines of someone in the crowd with a specially modified cane or umbrella. Hopefully you could make a small enough pinprick that the security doesn't realize something serious is going on until too late. in the cold war era, a Russian official was poisoned by the injection of a pellet of a toxic material (I forget exactly what) by means of an umbrella gun - at the time of the injection he had complained about a person accidentally jabbing him with an umbrella (on a crowded sidewalk) IIRC, it was ricin. And the Mythbusters did their own version of the umbrella gun during either the first or second ice bullet episode. |
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Post by the light works on Apr 2, 2014 15:16:32 GMT
in the cold war era, a Russian official was poisoned by the injection of a pellet of a toxic material (I forget exactly what) by means of an umbrella gun - at the time of the injection he had complained about a person accidentally jabbing him with an umbrella (on a crowded sidewalk) IIRC, it was ricin. And the Mythbusters did their own version of the umbrella gun during either the first or second ice bullet episode. thanks, that was one of the accounts in my "writers guide to firearms" book; which I have been unable to find. |
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Post by mrfatso on Apr 2, 2014 15:57:02 GMT
IIRC, it was ricin. And the Mythbusters did their own version of the umbrella gun during either the first or second ice bullet episode. thanks, that was one of the accounts in my "writers guide to firearms" book; which I have been unable to find. IIRC he wasn't a Russian Official, but a dissident Eastern European Journalist and playwright, killed on Waterloo bridge. He was working for the BBC at the time, so the sometimes mention his death as he was one of theirs. |
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