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Israeli Company Creates Nano-Armor
Izeickl writes "According to IsraCast, an Israeli company has created materials made of inorganic fullerene-like nanostructures (IFs) which have amazing shock absorbing properties. During preliminary tests, these materials, which are five times stronger than steel, have successfully resisted to steel projectiles generating pressures as high as 250 tons per square centimeter. These materials could be incorporated in "nanoarmors" able to protect soldiers or police forces within three years."
more muzzle velocity, yes. better armor piercing ability, not likely.
As a physics major, let me explain my understanding of firearms:
I believe the bullets would (all else being equal) receive the same kinetic energy (1/2*m*v^2), so if the bullet was half the mass, it would go sqrt(2) times as fast. At least at the end of the muzzle. After that (and to a lesser extent, before) air resistance affects the bullet proportional to v^2. Since v^2 is twice as large for the smaller bullett, the force would be twice as large, and due to the lower mass, the lighter bullet would decelerate much quicker (starting at 4x). This is a rather complex differential equation (because of the square), but what's likely to happen is that at any large distance, the lighter bullett will probably hit the target moving slower.
Now, when the bullet impacts the target I believe it's the pressure that actually does the damage. Pressure is force per unit area, and the areas would be the same (although here the analysis could possibly fail, if the lighter bullet held a pointier shape for longer). At point-blank range (or ignoring air resistance) and treating the force the target exerts as spring-like (probably good approximation for armor), the force needed to stop the bullets would be the same on each bullet (because the energy is the same so they would deform the target the same amount). Factoring air resistance back in, the lighter bullet will reach the target with less energy, and so exert less pressure. If the lighter bullet doesn't deform, it's possible that the pressure would be greater, dealing more damage.
Conclusions:
1. A lighter bullet will hit the target at a slower velocity.
2. Assuming the same deformation upon impact, the lighter bullet will deal less damage.
3. If the heavy bullet deforms and the light doesn't, the light one *might* do more damage.
This is my best guess, but it's possible I made a mistake somewhere.
A few quotes to back you up.
i ts-components.html
"There is a myth of "cop killer bullets" that can penetrate body armour and then expand to kill the officer wearing it. This is pure fantasy. A bullet can be designed to penetrate armour or it can be designed to expand in soft tissue. It CANNOT do both. The "teflon" coating on the much maligned Black Talon ammunition is simply an aid to reducing barrel fouling in the handgun. It does nothing to enhance the bullet's ability to penetrate body armour. Many hunting bullets are coated with different compounds these days." http://www.nfa.ca/for-journalists/ammunition-and-
"Armour piercing bullets are a specific design which incorporates a hard steel or tungsten carbide penetrator inside the bullet's core. Only ammunition with this hard penetrator design is considered to be armour piercing. When the bullet impacts armour, it begins to flatten. As the nose flattens, the hard penetrator continues forward into the armoured surface while being supported by the bullet as it continues to flatten.
Armour Piercing bullets do not explode, fragment or do any of the things you might see in a Hollywood movie. They are a simple kinetic energy penetrator. AP bullets are mainly found in military ammunition." http://www.nfa.ca/content/view/162/76/
And yes, I feel like being a Karma Whore today.
Life is not for the lazy.
"How about teflon-coated bullets?"
FWIW:
The teflon coating found on many armor-piercing rounds for small arms has no effect on the armor-piercing ability of the ammunition. The teflon coat is to protect the barrel from excess wear caused by the hard materials of the projectile. Armor-piercing properties come from the composition of the projectile or from a insert of a harder substance incorporated into the projectile.
Friends help you move... Real friends help you move bodies...
Nice to know your vest will stop a handgun but if a
Most modern armies use body armor and helmets even if they don't help against rifle bullets. Why? To protect against shrapnel (which iirc accounts for about 80 % of casualties in full scale warfare). So even if this doesn't protect against rifle bullets, it isn't exactly useless as long as it's an improvement over the standard kevlar stuff.
The primary determinant for how much energy the bullet receives is how long the bullet stays in the barrel, giving the powder time to burn; this is why, for instance, a carbine has a much higher muzzle velocity than a pistol firing the same round. (On the other side of the coin, you could make a pistol chambered for rifle rounds, but it wouldn't be terribly useful; most of the powder would escape from the muzzle and burn up in the air, creating a hell of a muzzle flash but no extra velocity.) So a lighter bullet will have a higher muzzle velocity, but it probably won't be enough higher (increasing as the square root of 1/mass) to give it equivalent energy to a heavier bullet. Barrel length and powder burn speed are the most important factors. Typical rifle rounds are in the 22 to 30 caliber range, while typical handgun rounds are in the 38 to 45 caliber range, and while the rifle bullets are longer, they still run a bit lighter on average than the handgun bullets -- but they have much, much higher muzzle velocity and energy.
.45 pistol round, about the biggest practical pistol caliber for most people, which will usually be about half again its weight. Guess which one hits the target harder?
...) One problem with small, fast bullets is that they can go right through the target, leaving a hole almost exactly the size of the bullet*, and not actually doing that much damage. Bullets which deform inside the target dump all their energy right there, and therefore have much more "stopping power." This is one reason, perhaps the primary reason, why the M16, despite having evolved into a pretty reliable weapon over the years since its disastrous first iteration in Vietnam, remains controversial. Many infantrymen, whose lives depend on "one shot, one kill," and medics, who see the results up close and personal (I've been both) believe that our troops would be better served by the older, heavier style of military rifle round. Not necessarily the 7.62 x 51 mm (NATO), which is overkill for anything but a sniper rifle or a machine gun, but say the 7.62 x 39 mm (Warsaw Pact) used in the AK. There's some benefit in being able to carry more ammunition with the smaller rounds ... but more benefit in being sure that the guy on the other end of your sights is going to go down when you hit him.
.45 ACP) are about the best single-round choice for self-defense there is, because not only will they take down the target, if you miss they're much less likely to go through three walls and kill your neighbor's toddler. Even better is a short-barreled 16-ga. shotgun.
You're right about lighter bullets losing velocity faster, of course, but it's not as much a determinant as you might think -- consider the difference between a 7mm rifle round, which is a mid-sized hunting round, and a
Now, all that being said, deformation on hitting the target is a good thing. (Er, good from the shooter's POV, not the target's
* Forget all that crap you hear about "cavitation" and "small hole going in, big hole coming out." It's a myth, based on studies of firing bullets into blocks of gelatin which do not behave, in the least, like human (or animal) bodies. If you're looking for a weapon for self-defense, you will always be better off with a bigger bullet, as long as you can handle the weapon. Period. And big slow bullets (e.g.,
The correlation between ignorance of statistics and using "correlation is not causation" as an argument is close to 1.
That would depend on how dense this stuff is.
In the Society for Creative Anachronism, people can fight in various amounts of steel armor and wield rattan swords. This always includes a helm and some other mandatory armor.
One man got the idea to make his mandatory helmet out of titanium. Titanium is stronger than steel, but less dense. When he went into combat that day with his new helmet, he took one good whack to the head that someone wearing a steel helm would have shrugged off. With his lighter titanium model, he was knocked unconscious and got a concussion. The helmet was undamaged, however.
It all goes back to physics: action, reaction, momentum.
Hail Eris, full of mischief...
E pluribus sanguinem