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• posted on December 20, 2012, 4:08 am
There's been a lot of talk about guns in here lately, and there's something I've always wondered about...
I don't know how far a regular pistol or rifle will shoot, but this web site about the battleship USS Missouri (which is the one that McArther accepted the Japanese surrender on at the end of WWII)
http://en.wikipedia.org/wiki/USS_Missouri_(BB-63)
states as follows:
"Missouri's main battery consisted of nine 16 in (406 mm)/50 cal Mark 7 guns, which could fire 2,700 lb (1,200 kg) armor-piercing shells some 20 mi (32.2 km)."
20 miles! Geez. Obviously, that's a lot farther than any rifle or pistol will shoot.
Is that because:
a) the gunpowder used in those cannons is more powerful than the stuff used in regular bullets,
b) or is it because the battleship's cannons are pointed upward to maximize range,
c) or is it that the cannon's barrel is longer so the power in the explosion acts on the projectile for a longer period of time, thereby accelerating the shell more than a bullet
d) or something else entirely.
It just strikes me as odd. I'm thinking that the ratio of lengths between a bullet in a rifle barrel and a shell in a cannon barrel would probably be pretty similar. So, what accounts for the cannon having 20 times the range? Is it just that the gunpowder used in the cannon is 20 times as powerful as than that used in bullets, or is it that the shell stays in it's barrel 20 times longer than a bullet and therefore receives 20 times as much of a push?
--
nestork

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• posted on December 20, 2012, 11:44 am

ALL of a), b), c) and more More powder is used, higher pressures are achieved
I think you need to re-shape your question to make it obvious The amount of pressure you build behind the projectile defines the amount of force exerted on it. The weight of the projectile affects how much resistance to acceleration the projectile has The length of the barrel affects how long that force is applied The weight of the projectile affects how long that force is applied to it.
It's a dynamic equation that allows for creative adjustment of how big, how heavy both the gun and the projectile can be and will be.
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• posted on December 20, 2012, 12:46 pm

All of the above-- I was on an mountain along the coast of Vietnam in 69. Naval Gunfire used to go overhead on its way to the highlands. holy crap! Never had the pleasure of seeing one up close-- but the projectile supposedly weighed in similar to a Volkswagen [bug? van?]
20 miles is pretty good-- but the German long guns of WWI could shoot as far as 75 miles-- Google the 'Paris Gun'.
Jim
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• posted on December 20, 2012, 4:37 pm

There are theorotical limitations on how far any simple gun can fire. The longest range gun was the V3 cannon (Tausendfuss) with mulitple charges. Range of over 100miles. German, designed to bombard London from France
http://en.wikipedia.org/wiki/V-3_cannon
I was bombed by the RAF using blockbuster bombs and put out of action before it could be used. But you can go and see what's left of it.
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• posted on December 20, 2012, 4:58 pm

The largest cannon I have ever heard of was Gerald Bull's HARP on the island of Barbados in the 1960s, constructed from two USN battleship gun barrels fitted end to end: http://en.wikipedia.org/wiki/Gerald_Bull#High_Altitude_Research_Program The original HARP idea (approx. 1960) was that it would be cheaper to launch satellites (then usually orbiting at 100 to 500 miles altitude) from reuseable guns rather than rockets expended in use: but Bull never got into orbit, (The maximum altitude mentioned here is 66 km.)
Bull was a fascinating individual, the youngest Toronto PhD ever (at 21) in his day, employed as a military researcher by the Canadian Defence Research Board, funded partly by the US Army gun research branch, and eased out because he seemed more interested in space research than weapons. Twenty years later he was active in 105 mm. artillery and ammunition supply, eventually assassinated in mysterious circumstances.
--
Don Phillipson
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• posted on December 21, 2012, 8:01 am

Interesting story that. I read somewhere that the idea of a satellite gun is not actually possible. There is a top limit to muzzle velocity that cannot be exceeded and is not sufficient to launch a satellite. Though a rail gun might.
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• posted on December 21, 2012, 3:23 pm
On Fri, 21 Dec 2012 00:01:28 -0800 (PST), harry

A satellite gun isn't possible, even if you could get enough velocity. An orbit must include the point of the last change in velocity. In the case of a bullet, it's at the end of the barrel so the orbit would include this point. The next orbit the would be satellite would intersect the ground somewhere next to the gun (where the gun was).
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• posted on December 21, 2012, 3:53 pm
On 12/21/2012 9:23 AM, snipped-for-privacy@att.bizzz wrote:

Ever heard of a recoilless rifle? "Every action has an opposite and equal reaction" I believe any "space projectile weapon" would have to operate with the same principles as a recoilless gun. ^_^
https://en.wikipedia.org/wiki/Recoilless_rifle
TDD
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• posted on December 21, 2012, 4:39 pm
On Fri, 21 Dec 2012 09:53:39 -0600, The Daring Dufas

If you're saying that a rocket can launch a satellite, then yes, I suppose it can. ;-) However, the same principle applies; the orbit must contain the last point of delta-V.
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• posted on December 21, 2012, 4:47 pm
On 12/21/2012 10:39 AM, snipped-for-privacy@att.bizzz wrote:

DUH!, I was under the impression you were discussing firing a gun in space from a satellite. Premature postification and text skimming error. ^_^
TDD
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• posted on December 21, 2012, 9:09 pm
On Fri, 21 Dec 2012 10:47:56 -0600, The Daring Dufas

I seem to remember the Soviets actually tried that from a manned space craft. It wasn't very successful as I recall.
I suppose if your satellite was a one shot and die thing it might work but a rocket is a lot more practical.
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• posted on December 21, 2012, 7:20 am

Pippa Middleton Involved In Paris Gun Scandal http://www.cinemablend.com/pop/Pippa-Middleton-Involved-Paris-Gun-Scandal-41456.html
Oh, you meant this Paris Gun
People who like The Paris Gun also like Rudolf Wiebe, Boo Hooray, Tom & Foley Not many people have scrobbled The Paris Gun recently. http://www.last.fm/music/The+Paris+Gun
(Sorry, couldn't resist!)
What is "scrobbling" you might ask?
Scrobbling a song means that when you listen to it, the name of the song is sent to Last.fm and added to your music profile.
I think I've got it! (-:
http://en.wikipedia.org/wiki/Paris_Gun
<<As a military weapon, the Paris Gun was not a great success: the payload was minuscule, the barrel required frequent replacement and its accuracy was only good enough for city-sized targets . . . The gun was capable of hurling a 94 kilogram (210 lb) shell to a range of 130 kilometers (81 mi) and a maximum altitude of 40 kilometers (25 miles, 131,000 ft) - the greatest height reached by a human-made projectile until the first successful V-2 flight test in October 1942. At the start of its 170-second trajectory, each shell from the Paris Gun reached a speed of 1,600 meters per second (5,250 ft/s) . . . Since it was based on a naval weapon, the gun was manned by a crew of 80 Imperial Navy sailors under the command of Vice-Admiral Rogge, chief of the Ordnance branch of the Admiralty. It was surrounded by several batteries of standard army artillery to create a "noise-screen" chorus around the big gun so that it could not be located by French and British spotters . . . The projectile reached so high that it was the first human-made object to reach the stratosphere . . . The Paris gun was used to shell Paris at a range of 120 km (75 mi). The distance was so far that the Coriolis effect - the rotation of the Earth - was substantial enough to affect trajectory calculations.>>
Fascinating!
-- Bobby G.
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• posted on December 22, 2012, 2:26 pm

-snip-
It is kind of like the recent rockets from Gaza-- Militarily, not so significant-- but the Palestinians called them a victory because of their longer range. more of Israel needs to be aware of them, now.
Jim
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• posted on December 22, 2012, 4:05 pm
<stuff snipped>

was
It's too bad that Palestinians don't understand that the rocket attacks hurt them and their quest for nationhood more than they hurt Israel.
Still, the German V1 and V2 rockets had a significant psychological effect on the British during WWII, although many historians say it only strengthened their resolve to fight back. If the German atomic research had come to fruition, the V2's lack of pinpoint accuracy wouldn't have been much of an issue.
I've often wondered how effective the Israeli blockade has been because it hasn't seemed to stop the flow of Iranian-made weapons into the Gaza Strip. Based on what's happening now, I don't see a good future for anyone in that part of the world. It would be ironic if the cradle of civilization turned out to be its grave, too. I fear that once the US has mostly withdrawn from the area, Islamic terrorist will re-focus their attacks on Israel.
I've always though Israel should have been carved out of Germany after WWII as a perpetual reminder of the cost of genocide both to the perpetrators and the victims.
-- Bobby G.
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• posted on December 20, 2012, 1:18 pm
nestork wrote:

Somewhere between a mile and a 3 1/2 miles.
--

____________________________
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• posted on December 20, 2012, 2:28 pm

Hi, During my time in 'Nam in the mid-late --60's I used to visit Marine sniper school, there I witnessed instructor one of original sniper during WW2 hitting at a target 500 meters away, he was aiming it at higher angle pretty well into the air. Canuck JTF sniper in Afghanistan confirmed kill at more that 2000yards. All law of simple physics. Read about Dr Bull who was assassinated by Israeli rumor was he tried to build monster canons for Saddam Hussein. Same as long range missiles.
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• posted on December 20, 2012, 4:47 pm
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• posted on December 20, 2012, 1:37 pm

A *lot* farther than you think it will. :-) Read on.

No, it isn't.

No. It is more powerful, but that's not the reason for the extremely long range.

Yes -- but if you do the same thing with a rifle, you'll get the same result: greatly increased range, compared to firing it with the barrel horizontal.

No. The muzzle velocity on those guns is in the neighborhood of 800 m/s, which is actually 15-20% *lower* than that of many common hunting rounds (e.g. typical muzzle velocity for a 30-.06 is around 880 m/s).

Yes -- because the battleship shells are so large, they are less affected by air resistance than are rifle bullets. I have a .243 rifle which fires an 85-grain round at a muzzle velocity of about 1000m/s. A quick back-of-the-envelope calculation shows that -- in the absence of air resistance -- if the barrel is elevated at an angle of 45 degrees, the bullet will travel over 100 kilometers before striking the ground. Obviously that won't happen, because it *is* subject to air resistance. While the battleship shell is subject to the same air resistance forces as the bullet, the magnitude of those forces in proportion to a 1200-kilogram shell is obviously much smaller than in proportion to a 6-gram bullet, and hence their effect on the trajectory of the shell is correspondingly much smaller.

No, actually, it's not -- the ratio is a *lot* *higher* for a typical hunting rifle than it is for those cannons. http://www.navweaps.com/Weapons/WNUS_16-50_mk7.htm
With an 800-inch barrel and a 64-inch projectile, the cannons have a ratio similar to that of most *pistols*.

It *doesn't* have "20 times the range." What makes you think that a rifle can shoot only one mile?

It's not.

It doesn't.

It doesn't.
It's all about angle of elevation, and the fact that battleship shells weigh two hundred thousand times as much as rifle bullets and consequently aren't affected nearly as much by air resistance.
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• posted on December 20, 2012, 3:38 pm
wrote:

If the cannonball is larger, it must be more affected by air resistance so something is wrong with your conclusions. Now, if the ratio of diameter to weight is different, then maybe what is postulated could be true.
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• posted on December 20, 2012, 4:17 pm

So you think a cannonball is more affected by air resistance than a BB ???

No, something is wrong with your reasoning. The *total* force of air resistance acting on the larger object is of course greater, but _in proportion to its mass_ it's much smaller.

You are overlooking the fact that the effect of air resistance is proportional to the surface area of the object, whereas its momentum is proportional to its mass and thus (if it is of approximately uniform density) to its volume -- hence the larger the object (assuming constant density) the *lower* the *proportional* effect of air resistance.
And *of course* the ratio of diameter to mass (not weight) is different.
Consider two solid spheres, one 1 cm in diameter, the other 2 cm in diameter. Since volume is proportional to the *cube* of the radius, the volume of the second is 8 times that of the first, and if they are made of the same material, the ratio of their masses is also 8:1, while the ratio of the diameters is 2:1. I'll leave it to you to calculate the ratio of the surface areas.