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  #1  
Old 06-30-2005, 08:55 AM
Whack-a-Mole Whack-a-Mole is offline
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What's the difference between a rifle (or gun) and a cannon?

Title pretty much says it all but for some examples:

You hear of the big guns on a battleship referred to as a naval rifle.

Tanks are described as using cannons...not rifles.

The F86 Sabre aircraft used a 20mm cannon. Its rival, the MiG-15 in some variants used a 12.7mm machine gun.

How is the distinction drawn between cannons and guns (or rifles)?
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  #2  
Old 06-30-2005, 09:01 AM
Sunspace Sunspace is offline
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I thought a rifle (of any size) had spiral slots or indentations or something inside the barrel to cause the shell/bullet to spin in flight and fly straighter and more accurately, while a cannon or gun (of any size)... didn't. I could be very wrong on this.
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  #3  
Old 06-30-2005, 09:07 AM
Whack-a-Mole Whack-a-Mole is offline
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Quote:
Originally Posted by Sunspace
I thought a rifle (of any size) had spiral slots or indentations or something inside the barrel to cause the shell/bullet to spin in flight and fly straighter and more accurately, while a cannon or gun (of any size)... didn't. I could be very wrong on this.
I was thinking about that but some tanks have a rifled barrel (although I think modern tanks use a smoothbore gun...could be wrong).
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  #4  
Old 06-30-2005, 09:16 AM
Raguleader Raguleader is offline
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Quote:
Originally Posted by Whack-a-Mole
Title pretty much says it all but for some examples:

You hear of the big guns on a battleship referred to as a naval rifle.

Tanks are described as using cannons...not rifles.

The F86 Sabre aircraft used a 20mm cannon. Its rival, the MiG-15 in some variants used a 12.7mm machine gun.

How is the distinction drawn between cannons and guns (or rifles)?
Yeah, basically a rifle is any firearm that has spiral grooves in the inside of the barrel (cleverly refered to as... rifling) which make the bullet spin like a football, improving accuracy at long range.

The reasoning that was explained to me for the differences between cannons and machine guns on fighters in the 40's and 50's was that a cannon fired explosive rounds, though in modern examples (such as the 20mm Vulcan canon used by American fighter planes) the cannons are externally powered, instead of gas-powered, so they wouldn't be considered a machine gun no matter what kind of bullets they spat out.

American tanks (and I think German ones too, dunno about anyone else) use Smoothbore cannons... no rifling. Hence, they're not rifles regardless of what else they're called. I think "Cannon" is just the catch-all phrase for "A firearm that fires really really big bullets".

Interestingly enough, most modern handguns (such as the Beretta 92) are also Rifles, due to the rifling used in their barrels, though in regards to hand-held firearms, it seems that the gun needs to be of a certain length to be considered a Rifle (Make it a bit shorter, it becomes a Carbine, remove the stock, it becomes a Pistol) "Gun" is a sort of catch-all phrase for any kind of firearm, as well as Air-guns (Think a regular gun, but it uses compressed air instead of exploding gasses to propel the bullet)

Also, in regards to the Sabre, early versions had six .50 calibre machine guns mounted in the nose.
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  #5  
Old 06-30-2005, 09:19 AM
Hypno-Toad Hypno-Toad is offline
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Rifle definately refers to the spiral grooves cut into the barrel. So a weapon can be both a rifle and a cannon. But not all cannons are rifles (The M-1 tank uses a smoothbore cannon. The round has fins to impart spin instead of rifling in the barrel). Likewise, not all rifles are cannons. Anyone who uses a hunting rifle can tell you that.

20mm seems to be the arbitrary point at which a weapon is called a cannon. I don't know if there is a technical difference or if everyone simply agreed on it for classification purposes.
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  #6  
Old 06-30-2005, 09:20 AM
Hypno-Toad Hypno-Toad is offline
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Man, I've got to be quicker if I want to be first on this board.
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  #7  
Old 06-30-2005, 09:52 AM
Pushkin Pushkin is offline
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Quote:
Originally Posted by Raguleader
American tanks (and I think German ones too, dunno about anyone else) use Smoothbore cannons... no rifling
I remember this from a "UK vs US" thread, the Abhrams tank uses a smoothbore cannon and the British Challenger uses a rifled cannon, so the Abhrams packs more of a punch.

And on a related note, what's the difference between a chain-gun and a machine gun, as found on the Challenger tank.
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  #8  
Old 06-30-2005, 10:03 AM
Hypno-Toad Hypno-Toad is offline
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Quote:
Originally Posted by Pushkin
And on a related note, what's the difference between a chain-gun and a machine gun, as found on the Challenger tank.
A machine gun is operated by the gunpowder in the bullets, either through the recoil of the shell, or the expanding gasses going down the barrel. A chain gun is externally powered by an electric motor. One difference this makes is that a dud round will stop a machine gun until the gunner clears the gun and pulls the trigger again. The chain gun will simply eject the dud round and keep going without interruption. Another difference is that chain guns can have a much higher rate of fire than a MG. MGs can still get up there. The german MG42 fired 1,200 rounds a minute. But a chaingun can pump out 3,000 RPM.
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  #9  
Old 06-30-2005, 10:17 AM
Padeye Padeye is offline
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I've never heard reference to a chain gun outside of a video game but Hypno-Toad's description of a rotary gun is right on. They are often called Gatling guns but that term is only correctly applied to the Civil war era hand cranked version. Not all actually eject rounds. The M-61 gun used in many US military planes has a continuous feed belt that sends rounds back into the drum, fired or not. This allows the belt and rotary barrels to come up to speed, fire a specified burst and come to a stop without throwing good rounds away. When all the usable rounds are fired the belt in the drum has alternating stretches of fired and live rounds that can be recovered when it is reloaded.
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  #10  
Old 06-30-2005, 10:57 AM
Cerowyn Cerowyn is offline
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Quote:
Originally Posted by Hypno-Toad
The M-1 tank uses a smoothbore cannon. The round has fins to impart spin instead of rifling in the barrel
Nitpick: The M1 uses a rifled 105 mm cannon. The M1A1 and M1A2 use a German 120 mm smooth bore cannon (designated M256 by the US DOD).
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  #11  
Old 06-30-2005, 03:23 PM
cornflakes cornflakes is offline
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Larger rifled guns have been designated as rifles, possibly to clear things up in the supply chain. I'd assume that a 16" rifle used different shells than a 16" smoothbore cannon.
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  #12  
Old 06-30-2005, 04:37 PM
Raguleader Raguleader is offline
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Quote:
Originally Posted by Cerowyn
Nitpick: The M1 uses a rifled 105 mm cannon. The M1A1 and M1A2 use a German 120 mm smooth bore cannon (designated M256 by the US DOD).
Hmm... I assumed that all the original M1s had been refit to M1A1 or M1A2 standards. So if I was correct in that assumption, then the M1s *used* a rifled cannon, but *use* a smoothbore now.

Was my assumption incorrectly made? If so, then on behalf of me I'd like to say "Oops."
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  #13  
Old 06-30-2005, 04:51 PM
Mk VII Mk VII is offline
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saying 'cannon' about an artillery piece is like calling the Queen Mary a boat - here, anyway. 'Cannon' gets reserved for aircraft (or light armoured vehicle) guns of 30mm or less with explosive projectiles.
Naval 'rifle' probably dates from the transitional period in the 19th c. when naval artillery was a mixture of rifled and smoothbored guns
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  #14  
Old 06-30-2005, 05:38 PM
kniz kniz is offline
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"This is my rifle and
this is my gun"

Said gun definitely has a smooth bore.
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  #15  
Old 06-30-2005, 08:07 PM
Padeye Padeye is offline
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No wonder I can never get long range accuracy.
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  #16  
Old 06-30-2005, 11:02 PM
Raguleader Raguleader is offline
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Quote:
Originally Posted by Padeye
No wonder I can never get long range accuracy.
Remember, it's not the muzzle velocity that counts, it's the trajectory of the shot.
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  #17  
Old 06-30-2005, 11:19 PM
David Simmons David Simmons is offline
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It all gets confusing and I'm not totally straight on all of it.

A cannon is the generic term for a large gun. How large? Well, some of them are refrerred to as 20 mm (0.787 in.) cannons.

In the artillery the term gun is often used to distinguish a relatively long barreled piece from a howitzer which is a cannon with a big bore and a short barrel useful for high angle, plunging fire.

A piece with a short barrel and a big bore intended to deliver plunging fire is also sometimes called a mortar.

A naval rifle is a cannon with a caliber of more than, say, 30. This means that the barrel length is 30 times the bore diameter. Most naval rifles are around 50 caliber.

Caliber also can refer to the diameter of the bore in small arms. Such as a 30 caliber hunting rifle.

These terms are all used, are historical and have grown up over a long period of time.
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  #18  
Old 07-01-2005, 10:07 AM
Hypno-Toad Hypno-Toad is offline
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Well, glad we got that all cleared up.
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  #19  
Old 07-01-2005, 10:20 AM
David Simmons David Simmons is offline
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Quote:
Originally Posted by Hypno-Toad
Well, glad we got that all cleared up.
Yeah. That's what you get for letting the hoi poloi do their own naming.
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  #20  
Old 07-01-2005, 11:39 AM
tomndebb tomndebb is offline
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Earlier related topic thread:

Cannon or Gun?

- - -

Quote:
The F86 Sabre aircraft used a 20mm cannon. Its rival, the MiG-15 in some variants used a 12.7mm machine gun.
[ nitpick ]

This sentence is misleading. The machine gun that the article mentions was mounted on a trainer. The actual combat MiGs were armed (as noted on the page) with a pair of 23mm cannon plus a 37mm cannon that combined to tear the hell out of anything that got in its sights. The F-86 was actually under-armed (until later models) with six .50 caliber (or 12.7mm) machine guns, which made killing the heavily armored MiG a hassle throughout the Korean war. (Interestingly, the Navy version, the FJ Fury, was armed with four 20mm cannon from the outset.)

[ /nitpick ]

The nomenclature "12.7mm machine gun" was simply the European mode of identifying the same bore diameter as the .50 caliber expression used by the U.S. Similarly, American weapons identified as .30 caliber were generally identified in Europe as 7.62 mm.
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  #21  
Old 07-01-2005, 12:07 PM
SlyFrog SlyFrog is offline
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Interestingly, in the U.S. Civil War I believe that some guns were referred to as "rifled cannons" (such as the Parrott) versus guns like the Napoleon (which I think was a "smooth bored cannon."

I think that anything higher than a small arm was effectively a form of artillery, which could be cannon (effectively direct fire), howitzers, or mortars (indirect fire).
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  #22  
Old 07-01-2005, 12:13 PM
Perderabo Perderabo is offline
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Look at the picture in this link. The text says:
"The Davy Crockett consisted of an XM-388 projectile launched from either a 120-millimeter (XM-28) or 155-millimeter (XM-29) recoilless rifle (the 120 millimeter version is shown above). "

Why is that thing called a "recoiless rifle". There isn't even a barrel involved.
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  #23  
Old 07-01-2005, 12:39 PM
Mk VII Mk VII is offline
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the barrel is the shiny thing in the top picture. It's an open-ended tube, all the blast goes out through the vent at the back. These tubes were usually rifled.
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  #24  
Old 07-01-2005, 12:47 PM
Perderabo Perderabo is offline
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Well, then that big thing at the front has fins. Those fins look like they would resist spinning. Do I guess it doesn't spin, and a center rod holding it in the barrel does spin?

Not that I'd argue with some dude wielding one of those. He wants to call it a rifle? Fine by me!
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  #25  
Old 07-01-2005, 05:12 PM
Pushkin Pushkin is offline
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Quote:
Originally Posted by tomndebb
The actual combat MiGs were armed (as noted on the page) with a pair of 23mm cannon plus a 37mm cannon that combined to tear the hell out of anything that got in its sights
Dammit I knew that from an old Airfix model my Dad and I made years ago when I was a kid. Its still hanging in my room in Polish Air Cavalry livery, complete with the three mentioned guns at the nose of the aircraft.

Quote:
Originally Posted by tomndebb
The F-86 was actually under-armed (until later models) with six .50 caliber (or 12.7mm) machine guns, which made killing the heavily armored MiG a hassle throughout the Korean war
And dammit I knew that as well From the UK History channel, another few viewings and I'll know what happened at Leyte Gulf in WWII too.

See kids, this is what happens when you don't apply your accumulated knowledge
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  #26  
Old 07-01-2005, 11:21 PM
Raguleader Raguleader is offline
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Quote:
Originally Posted by tomndebb
This sentence is misleading. The machine gun that the article mentions was mounted on a trainer. The actual combat MiGs were armed (as noted on the page) with a pair of 23mm cannon plus a 37mm cannon that combined to tear the hell out of anything that got in its sights. The F-86 was actually under-armed (until later models) with six .50 caliber (or 12.7mm) machine guns, which made killing the heavily armored MiG a hassle throughout the Korean war. (Interestingly, the Navy version, the FJ Fury, was armed with four 20mm cannon from the outset.)

Yaknow, this is the first time I've heard the MiG-15 refered to as "Heavily armored". My understanding of the plane was that it was a lightly armored, heavily armed, very agile interceptor. But yeah, the .50 cal did lack the punch of the 20's later used.
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  #27  
Old 07-02-2005, 12:10 AM
Princhester Princhester is online now
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Quote:
Originally Posted by Hypno-Toad
The round has fins to impart spin instead of rifling in the barrel
Where do the fins go? Does the barrel have slots, or do they flip out as the round leaves the barrel or are they at the back inside the diameter of the round like a mortar?
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  #28  
Old 07-02-2005, 12:23 AM
David Simmons David Simmons is offline
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Quote:
Originally Posted by Princhester
Where do the fins go? Does the barrel have slots, or do they flip out as the round leaves the barrel or are they at the back inside the diameter of the round like a mortar?
The round is mounted on a sabot that closely fits and seals the bore against loss of pressure. The diameter of the sabot is slightly larger than that of the projectile When the round and the sabot exit the muzzle, the sabot drops away since it has high aerodynamic drag and the projectile proceeds on its own with the fins imparting spin.
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  #29  
Old 07-02-2005, 12:29 AM
Cerowyn Cerowyn is offline
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Quote:
Originally Posted by Raguleader
Hmm... I assumed that all the original M1s had been refit to M1A1 or M1A2 standards. So if I was correct in that assumption, then the M1s *used* a rifled cannon, but *use* a smoothbore now.

Was my assumption incorrectly made? If so, then on behalf of me I'd like to say "Oops."
Of the 3,273 original M1s, a total of 998 are being upgraded to A2 specifications, in lieu of new production. (The most recent program was scheduled to end last year, but I don't know what the status of it is.)

Excluding Abrams produced for foreign countries, 5,017 M1A1s were produced for the US Army and USMC. Just 77 tanks were built as M1A2s from the ground up, but as mentioned above nearly a thousand have been converted from M1s.

Incidently, the new SEP (system enhancement package) was added to 240 M1A2s, and I believe it will eventually be rolled out to all A2s. Next on the horizon for the Abrams is said to be a new engine, as the current one has been out of production since 1992.
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  #30  
Old 07-02-2005, 07:58 AM
SenorBeef SenorBeef is offline
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Quote:
Originally Posted by Hypno-Toad
20mm seems to be the arbitrary point at which a weapon is called a cannon. I don't know if there is a technical difference or if everyone simply agreed on it for classification purposes.
20mm is the point where you can practically start loading rounds with explosives.

Quote:
Originally Posted by Padeye
I've never heard reference to a chain gun outside of a video game but Hypno-Toad's description of a rotary gun is right on. They are often called Gatling guns but that term is only correctly applied to the Civil war era hand cranked version.
Some rotary guns are chain guns, but the terms are not synonymous. There are chain guns that have one barrel, such as on the Bradley and Apache. And as far as the term "gatling gun" - it's come to refer to any multibarreled automatic weapon, even if the original didn't have that exact functionality.

Quote:
Originally Posted by Perderabo
Why is that thing called a "recoiless rifle". There isn't even a barrel involved.
Recoilless rifles are essentially tubes that launch rockets. This is to distinguish them from explosive-launched projectiles.
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  #31  
Old 07-02-2005, 12:27 PM
tomndebb tomndebb is offline
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Quote:
Originally Posted by Raguleader
Yaknow, this is the first time I've heard the MiG-15 refered to as "Heavily armored". My understanding of the plane was that it was a lightly armored, heavily armed, very agile interceptor. But yeah, the .50 cal did lack the punch of the 20's later used.
It seems you are right and my aging memory had confused "toughness" (construction integrity such as that demonstrated by the B-17) with armor:Soviet pilots regarded the MiG-15 as much sturdier than the F-86, and it seems evident that the MiG-15 featured the famous "tractor toughness" of the best Soviet gear. Pilots warmly called it the "samolyot-soldaht (soldier aircraft)". Many pilots insisted insist that MiG-15s that were claimed as "kills" often made it back home and lived to fight on.
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  #32  
Old 07-02-2005, 12:58 PM
Padeye Padeye is offline
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Quote:
Originally Posted by SenorBeef
Some rotary guns are chain guns, but the terms are not synonymous. There are chain guns that have one barrel, such as on the Bradley and Apache.
Fair enough but can you give me a definition for chain gun?
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  #33  
Old 07-02-2005, 02:18 PM
Pushkin Pushkin is offline
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Quote:
Originally Posted by Padeye
Fair enough but can you give me a definition for chain gun?
From Wikipedia

Quote:
Rather than being dependent upon recoil to actuate the system, a chain gun instead depends on an external motor. The motor drives the chain, which slides the bolt assembly back and forth to load, fire, extract and eject cartridges.
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  #34  
Old 07-02-2005, 03:12 PM
Raguleader Raguleader is offline
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Heh, on the subject of B-17s and armor, I read in The Mighty Eighth (by Gerald Astor, IIRC) that the only armor plating on the B-17Gs was located under the seats of the flight crew "...because they knew what they wanted to protect."

And on the subject of cannon rounds vs. bullets, I seem to recall reading somewhere that they had .50 calibre machine gun rounds with explosive tips. I suppose they probably weren't very practical to produce or use (don't know how much use the amoutn of explosive you could fit in something that small would do vs. a solid slug)

Also, don't modern 20mm cannon rounds used on fighter planes tend to be solid slugs? A friend told me they rely on their insanely high refire rate to basically shred a target to pieces rather than try to blow them up.
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  #35  
Old 07-03-2005, 01:32 PM
Ficer67 Ficer67 is offline
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Another possible difference is the propellant charge. The propellant in some weapons is separate from the projectile. This way the weapon can fire multiple distances without changing the elevation. All of the old cannon, and firearms had this capability, where a gunner could put more or less powder into the cannon. Couldn't this be a consideration?
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  #36  
Old 07-03-2005, 04:50 PM
JRDelirious JRDelirious is offline
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Quote:
Originally Posted by SenorBeef
Recoilless rifles are essentially tubes that launch rockets. This is to distinguish them from explosive-launched projectiles.
Actually, they first of all are rifled, unlike a smoothbored bazooka, and do have the alternative of providing the propulsion through a cartridge charge OR being the aiming tube for a proper rocket. Cite.

In the case of the Davy Crockett, what you have is the 105mm RR being used as launching device for a really, really big-arsed RPG. A nuclear RPG.
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  #37  
Old 07-04-2005, 11:10 AM
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As for 20mm cannon rounds being standard FMJ... that's not true either. US fighters usually fire either Armor Piercing/Incendiary or High Explosive/Incendiary rounds. Despite the ridiculous rate of fire, hitting other airplanes is still pretty tricky- they need all the help they can get, including HE rounds.

http://www.f-16.net/f-16_armament_article5.html
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  #38  
Old 07-04-2005, 11:42 AM
tomndebb tomndebb is offline
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Quote:
Originally Posted by Ficer67
Another possible difference is the propellant charge. The propellant in some weapons is separate from the projectile. This way the weapon can fire multiple distances without changing the elevation. All of the old cannon, and firearms had this capability, where a gunner could put more or less powder into the cannon. Couldn't this be a consideration?
Large guns certainly use this sort of propellant, but a 20mm cannon or 30mm cannon has never been loaded that way. They are fed by pre-loaded, cased amo belts, just like machine guns--hence the question of the OP. (Even the 75mm cannons they put on a few WWII aircraft came with cased propellants so that they could be fired automatically without messing around with measuring the charge.)
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