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G: Guns, guns, guns

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Sadurian Mike
385236.  Fri Jul 25, 2008 2:50 pm Reply with quote

A gnother gnu.

Janet H
385241.  Fri Jul 25, 2008 2:55 pm Reply with quote

'I'm a Gnu, I'm a Gnu
The g-nicest work of g-nature in the zoo
I'm a Gnu, How do you do
You really ought to k-now w-ho's w-ho's
I'm a Gnu, Spelt G-N-U
I'm g-not a Camel or a Kangaroo
So let me introduce,
I'm g-neither man nor moose
Oh g-no g-no g-no I'm a Gnu'

Sadurian Mike
385267.  Fri Jul 25, 2008 3:39 pm Reply with quote

Anti-tank guns.
Part Two: Improvements and ammunition development

After the initial development by the Germans, all nations looked at anti-tank guns, not least to equip their tanks. The guns were all fairly small, in the 25mm-40mm range, as the armour of tanks at that time was also light.

By the time war broke out in 1939, the best anti-tank gun* was the British 2pdr (40mm). The Germans had their seminal 37mm Pak 35/36, and the Russians used a slightly modified version of the same gun, although they were in the process of upgrading to 45mm calibre using the same gun chassis. Other nations were similarly armed.

The British OQF 2pdr was an excellent anti-tank killer because it fired a solid projectile at a high muzzle velocity. It was accurate, fast to load and lay onto the target, and had excellent penetration. Its famous drawback, however, was that it was such a specialised tank killer that the ammunition did not adapt well to fire high explosives (needed to tackle infantry and other anti-tank guns). The high velocity meant that the shell had to be strong, not a problem with the solid steel of the armour-piercing shot but the requirement for thick walls meant that any HE filler was minimal.

Armour on tanks soon started increasing, and ways to improve the performance of the anti-tank guns were needed. The obvious answer was so simply increase the calibre of the weapon, thus enabling a larger round to be fired and a greater amount of propellant, thus giving higher muzzle velocities and so imparting more energy at the point of strike.

This approach stumbled onto a problem that was to dog weapon design for the rest of the war; the solid steel round could only be fired at increasing velocities until it reached the point where it would simply shatter against armour. What was needed was a way to strengthen the round itself, and the ammunition was usually strengthened with tungsten (or similar) in various ways. There were caps, cores and finally the develpment that we stil use today; the discarding sabot.

The discarding sabot round faces the problem that a large amount of propellant requires a large shell, and thus a large round; but a large round is heavier and so a good deal of the propellant's effects are wasted just in attaining the same velocity because of the extra weight. The sabot round has a lightweight "shoe" that fits around a tungsten (depleted uranium in modern ammunition) steel dart. The large base section of the sabot allows the propellant to fire it out at high velocity, at which point it falls away from the dart. The small dart thus travels at a higher velocity than it would be able to achieve without the sabot.

Wiki's explanation of ammunition types.

Distinct calibre groupings were seen as all nations improved their anti-tank guns; first there were the early 25mm-40mm weapons, which were quickly seen as insufficient, then came guns in the 47mm-60mm range (the British OQF 6pdr was of 57mm calibre), and finally 75mm-90mm. The Russians and Germans both increased even on these, with the Russians fielding 100mm and 122mm anti-tank guns, and the Germans using the enormous 128mm on their Jagdtiger self-propelled anti-tank gun.

Size, however, wasn't everything. The muzzle velocity had a great deal to do with the effectiveness of a gun and (for example) the 152mm howitzers employed in Russian self-propelled assault guns were not as good tank killers as the higher velocity German 88mm L/71.

The length of barrel usually means a higher muzzle velocity, as the propellant is pushing the round for longer before dissipating. This is seen as an "L" number after the calibre, and denotes the length of barrel in terms of the calibre. For example, the Germans fielded two 88mm anti-tank guns; the 88mm L56 (as seen on the Tiger tank), and the 88mm L71 (as seen on the King Tiger and Jagdpanther). The first gun was 88x56=4 928mm long, whereas the second was 88x71=6 248mm long. As a rough guide to the effectiveness of an anti-tank gun, both the calibre and the length (L) need to be taken into account.

Note that for howitzers and guns firing high explosive, the length of the barrel and muzzle velocity are irrelevant, except in so far as they affect accuracy. The effectiveness of an HE shell is determined only by the weight of explosive it carries (hence usually the calibre), and not the muzzel velocity. One quick and dirty way to tell a gun intended for anti-tank use as opposed to infantry support is to compare barrel lengths. The two guns below are the German 75mm IG18, an infantry gun for close support, and the 75mm Pak40 anti-tank gun. Both of the same calibre, but with very different muzzle velocities and tank killing ability.

*The German 88mm proved a more potent tank killer but this was envisaged and designed as an anti-aircraft gun rather than an anti-tank gun. It was used in extremis in the anti-tank role, and was only later modifed to be used as a dedicated anti-tank gun.

Last edited by Sadurian Mike on Mon Mar 30, 2009 8:54 pm; edited 1 time in total

385584.  Sat Jul 26, 2008 10:11 am Reply with quote

I get totally depressed when I think of the resources and intellect that are still spent on developing ever more efficient ways to drive hot metal through human flesh. :-(

385590.  Sat Jul 26, 2008 10:30 am Reply with quote

Alright, the curvature of the earth thing is a bit contentious, but naval guns do have to take into account the rotation of the earth.

Dr. Know
385594.  Sat Jul 26, 2008 10:38 am Reply with quote

they're shooting people in the belly button now? That can't be too flattering. Taking the curvature of the earth into account. ;)

Sadurian Mike
385650.  Sat Jul 26, 2008 1:27 pm Reply with quote

Nigelblt wrote:
I get totally depressed when I think of the resources and intellect that are still spent on developing ever more efficient ways to drive hot metal through human flesh. :-(

Welcome to the human race.

Dr. Know
385652.  Sat Jul 26, 2008 1:29 pm Reply with quote

Whoa, way to kill a mood, Mike.

Sadurian Mike
385663.  Sat Jul 26, 2008 1:45 pm Reply with quote

It's true though, dr.know.

Having studied military history and all its consequences, I think Nigelblt is quite correct in feeling depressed about the amount of time and energy devoted to warfare. It is not one of mankind's most laudable endeavours, depite any justification it might have on a local level.

That said, the technology and social history behind the development of war machines and war is very interesting and has brought us some unexpected benefits along the way.

I am a military history nut, wargamer and self-confessed tank fanboy, but I have no more wish to kill or see people killed than the next man. I am currently reading an account of Barbarossa, the 1941 German invasion of Russia, and it still makes me shake my head in wonder at what humans will do to each other or put up with.

War is nasty.

That doesn't make it less interesting or less worthy of study, but Nigelblt's post, or one like it, is completely justified in a thread about guns.

Dr. Know
385664.  Sat Jul 26, 2008 1:51 pm Reply with quote

yes, I know as well as any one the nastiness of war. As mentioned on another thread, I come from 3 generations of soldiers.

I share your opinion on how brutal but fascinating war can be. If i was to some up the german invasion of russia, i'd say "The germans went in and froze to death." But that's obviously quite undetailed, and inappropriately light hearted. :)

Sadurian Mike
385669.  Sat Jul 26, 2008 2:01 pm Reply with quote

The German invasion and the subsequent offensive and counter-offensive nature of warfare on the Russian Front are fascinating to study and a must if you want to learn about why Hitler was ultimately defeated. Alan Clark's "Barbarossa" is possibly a bit weighty for the relative newcomer, but there are plenty of sources out there that cover the four-year conflict in less detail and are more digestible.

The '41-'45 Russian Front helped define our modern world and I do sometimes wonder why it is not covered in school history.

Dr. Know
385670.  Sat Jul 26, 2008 2:08 pm Reply with quote

I didn't know the russians fought right the way up till '45.

Sadurian Mike
385672.  Sat Jul 26, 2008 2:21 pm Reply with quote

dr. know wrote:
I didn't know the russians fought right the way up till '45.


They were the guys that took Berlin and forced the German surrender. The Allies would have struggled in the mass street brawl that the fight for Berlin became, but the Russians had become experts by that stage, as well as having enough force to smash Berlin and also drive south to take Romania, Hungary and so on.

Not only that, but they also fought the Japanese to retake Manchuria, Korea and the Kuril Islands at the last gasp of the war in the Pacific.

The forces and fighting on the Russian Front made anything in the West look like a skirmish.

Dr. Know
385673.  Sat Jul 26, 2008 2:23 pm Reply with quote

Thanks for that, Mike. Your like Qikipedia, or something...:)

Sadurian Mike
385674.  Sat Jul 26, 2008 2:24 pm Reply with quote

Only for military stuff. Don't ask me about popular culture, music or anything important.

If you want to brush up the Eastern Front during WWII, have a peek at the Wiki page.

The statistics alone make for jaw-dropping reading (like 10.5 million Soviet, and 5 million German and Axis casualties).


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