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zeldapsychology
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13 Sep 2009, 10:53 am

I know obviously it depends on the make of gun and bullet. I know shooting it into the air it comes down faster and therefore strikes and at times kills but I was thinking MINUS any wall/obstacle how long can a bullet travel just through air?



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13 Sep 2009, 11:00 am

About 2 miles. People can actually hit targets at 1 mile.

Myth Busters did a show on the bullets fired into the air issue, and found that bullets shot straight up tumble, because they stop at the top and lose their spin, so they come down a lot slower, and are not lethal. Bullets shot at an angle into the air keep their spin and stay lethal for the entire trajectory.


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Danielismyname
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13 Sep 2009, 11:10 am

Straight up, it doesn't come down any faster until it starts getting close to terminal velocity and gravity pulls it back down. It won't kill you. It only kills when it's not straight up, so the projectile still flies on a ballistic trajectory.

A .22LR from a rifle (least powerful common firearm for the most part), can travel a couple of thousand meters (it can penetrate a human skull out to several hundred). Pistols are around this as they usually fire less aerodynamically stable projectiles compared to centerfire rifle rounds.

Centerfire rifles, a few to several kilometers at the most efficient angle for range (45).

Far.



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13 Sep 2009, 5:56 pm

If you box the ammo, and ship it to Diego Garcia from the US, about 12,500 miles or so...;)



Klint
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13 Sep 2009, 6:57 pm

duke666 wrote:
About 2 miles. People can actually hit targets at 1 mile.

Myth Busters did a show on the bullets fired into the air issue, and found that bullets shot straight up tumble, because they stop at the top and lose their spin, so they come down a lot slower, and are not lethal. Bullets shot at an angle into the air keep their spin and stay lethal for the entire trajectory.


You beat me to it :P



ruveyn
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13 Sep 2009, 7:29 pm

Klint wrote:
duke666 wrote:
About 2 miles. People can actually hit targets at 1 mile.

Myth Busters did a show on the bullets fired into the air issue, and found that bullets shot straight up tumble, because they stop at the top and lose their spin, so they come down a lot slower, and are not lethal. Bullets shot at an angle into the air keep their spin and stay lethal for the entire trajectory.


You beat me to it :P


A calibre 50 machine gun can hit targets at four miles. Obviously the gun is aimed up at a 45 degree angle or there abouts to produce this range.

Artillery shells from 16 naval rifles can hit target 25 or 30 miles away. It depends on the charge that is used.

Gerald Bull's super canon was capable of firing a shell into orbit. The canon was about 600 feet long.

ruveyn



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13 Sep 2009, 8:56 pm

zeldapsychology wrote:
I know obviously it depends on the make of gun and bullet. I know shooting it into the air it comes down faster and therefore strikes and at times kills but I was thinking MINUS any wall/obstacle how long can a bullet travel just through air?

4 miles max for the .50BMG sounds about right. What are you using this information for?


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13 Sep 2009, 9:22 pm

John_Browning wrote:
What are you using this information for?

Thank you for the information my friend! Allah smiles on you this day my friend!

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zeldapsychology
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13 Sep 2009, 9:26 pm

John_Browning wrote:
zeldapsychology wrote:
I know obviously it depends on the make of gun and bullet. I know shooting it into the air it comes down faster and therefore strikes and at times kills but I was thinking MINUS any wall/obstacle how long can a bullet travel just through air?

4 miles max for the .50BMG sounds about right. What are you using this information for?



LOL! I'm an Aspie and as such I tend to think of odd questions that I want answers too and that'll I'll never use (like the speed of a bullet question) Just spur of the moment curiosity I think it's an Aspie thing LOL! :-) I'll never forget saying I'm so curious about Psychology if I was a cat I'd be dead (you know the saying "Cuoriosity killed the cat?") LOL! The joys of Aspienss wanting to know odd information for no apparent reason YA!! !! !! !! !



Ambivalence
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14 Sep 2009, 4:27 am

About shooting a bullet straight up, if there was no air, it would come down with exactly the same speed it left the barrel with. A certain amount of kinetic energy (magnitude A) goes into the bullet; as the bullet moves higher this becomes potential energy. When it reaches the highest point it has potential energy equal to the kinetic energy it started with (also magnitude A). As it falls this is converted back to kinetic energy, and when the bullet reaches ground level again all the potential energy has been converted back to kinetic energy, so it would reach the ground at exactly the same speed it left.

In practice, air resistance slows it down, so it reaches a high point with less than A energy left, and is slowed down further on the way down. Tumbling and so on increase the air resistance, which slows it further, but so long as the gun is not fired in a vacuum the bullet will always land slower than it is fired, even if it doesn't tumble at all.


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iamnotaparakeet
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14 Sep 2009, 6:24 am

ruveyn wrote:
Klint wrote:
duke666 wrote:
About 2 miles. People can actually hit targets at 1 mile.

Myth Busters did a show on the bullets fired into the air issue, and found that bullets shot straight up tumble, because they stop at the top and lose their spin, so they come down a lot slower, and are not lethal. Bullets shot at an angle into the air keep their spin and stay lethal for the entire trajectory.


You beat me to it :P


A calibre 50 machine gun can hit targets at four miles. Obviously the gun is aimed up at a 45 degree angle or there abouts to produce this range.

Artillery shells from 16 naval rifles can hit target 25 or 30 miles away. It depends on the charge that is used.

Gerald Bull's super canon was capable of firing a shell into orbit. The canon was about 600 feet long.

ruveyn


That super cannon must have a high muzzle velocity.

Here is the derivation of the range equation for projectiles that DON'T go into orbit... http://scienceworld.wolfram.com/physics/Range.html

For the range equation 45° is optimum.



Ambivalence
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14 Sep 2009, 8:56 am

Though that range equation doesn't take air resistance into account, in practice the optimum range will be achieved with an angle somewhere near 45 degrees, depending on the gun in question.

There's a long history of people trying to fire projectiles into orbit - the aforementioned Gerald Bull who designed the supergun and who was subsequently assassinated by Mossad (*ahem* probably by Mossad) was the lead engineer of one of them, HARP, before he went to work for Saddam.


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iamnotaparakeet
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14 Sep 2009, 9:23 am

Ambivalence wrote:
Though that range equation doesn't take air resistance into account, in practice the optimum range will be achieved with an angle somewhere near 45 degrees, depending on the gun in question.

There's a long history of people trying to fire projectiles into orbit - the aforementioned Gerald Bull who designed the supergun and who was subsequently assassinated by Mossad (*ahem* probably by Mossad) was the lead engineer of one of them, HARP, before he went to work for Saddam.


Air resistance decreases the maximum range, so the range equation would give the maximum range without atmosphere. It is an upper limit.

If you care to account for the force of drag in the equation, go ahead.



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14 Sep 2009, 12:33 pm

Other people have provided better answers than me on this, but I'd like to point out the range of a bullet is dependant upon the caliber of the bullet as well the length and rifle twist on the barrel as well as the size of the charge firing the bullet.

A 'hot load' cartridge will fire bullet further than either a cold load or standard load. Furthermore, a longer barrel will translate to a higher muzzle velocity as the bullet clears the barrel, which again translates to increased range over a gun of the same caliber shooting the same load but with a shorter barrel.

Also, for what it's worth, a rifle shooting a .50 BMG will have accurate lethality within a range of two miles, further than that, the bullet will still be lethal, but with increasing inaccuracy for another 2 miles or so.


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Erminea
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14 Sep 2009, 2:31 pm

A tad off maybe but when my physics teach (+/- 25 years ago) told us/me that when one fires a gun perfectly horizontal and at the exact same time drops a bullet at the same height the other bullet leaves the barrel, (if the earth's surface was flat, no wind.... ), BOTH hit the ground at the same time.

At the time I could hardly believe this but in that ideal situation it would.... for Newton (nasty fellow btw) would pull both towards the surface with the same force. I.e. gravity.

But yeah anyway, it depends of course.... the angle of the barrel, the begin speed of the bullet, the thickness of the bullet (caliber), wind direction and other variables I'm forgetting here. No easy or simple answer thus.



ZEGH8578
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14 Sep 2009, 3:21 pm

it usually depends on the length of the barrel really. i bet its been mentioned allready. cba to read the whole lot of replies :D

tiny guns, short range.

long guns, long range.

on rifles, the bullet doesnt even fit the barrel. try. it doesnt. the barrel forces it through, and spits it out. quite impressive physics, really.


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