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The Great War (1914-1918) Forum

Remembered Today:

Is this an enormous field gun ?


arantxa

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Back on topic, with another interminable history lesson.

Ex-Gunners, please excuse my lazy use of the word ’weapon’ for the piece rather than the projectile. (”The weapon of the artillery is the shell – the gun is merely a means of delivery.”)

Two more titbits about the original photos (and I apologise if I'm teaching my grandmother to suck eggs, here) ...

  • I don't think we're seeing the whole weapon. That load on the right appears to be only part of the mounting or carriage. It looks far too tall and narrow to be stable when firing a weapon that large. I suspect there's at least one more load on wheels out of shot. In the pic of the British 9.2 How in my Post #19, above, there are three loads: the barrel & breech on the left, the mounting on the right and the ground firing platform in the middle. (In British terminology, if it has wheels and can be moved about complete, it's a carriage; if it has no wheels and sits on the ground or is fixed to the floor or deck, it's a mounting.) A piece as large as the one in the photos would need quite a large, stable platform on which to set the mounting before the barrel & breech could be put into the saddle which allows elevation, traverse and recoil.

  • The breech looks interesting. Smaller weapons (eg the 18 pdr) fired 'fixed' rounds of ammunition: the projectile was fixed into the mouth of a metal cartridge case, making a complete round which resembles a giant rifle round. The whole thing was picked up as one item, rammed into the breech, which was then closed, and fired. The breech was then opened and the cartridge case ejected. The breech was generally closed for firing by a sliding block. When the charge fired, it was the cartridge case itself which sealed the back end of the weapon (‘obturation’ in the jargon) to prevent the escape of propellant gasses. The sliding ‘breech block’ merely supported the rear of the case, preventing it from moving rearwards on firing. The French 75 mm field gun, the famous soixante-quinze, which used fixed ammunition, was a little unusual in having the other kind of breech closure, more common on larger pieces.

Above a certain size, a fixed round becomes too unwieldy so the projectile and propellant charge are loaded separately. First, you load and ram the 'bullet' and then you place the charge in the breech. Most such ammunition (at least in British and American service) dispenses with a case for the cartridge which is simply contained in fabric bags. For a gun with all charges the same size, there's usually just one cylinder-shaped bag, for howitzers (and gun-howitzers) where the gunner can vary the charge at the point of loading, there are two or more bags, often colour coded but always clearly marked, fastened or tied together with breakable ties. To fire at maximum charge you put the lot in the hole and fire it. As I mentioned, the M109A1 had eight levels of charge: for Charge 8 you used all the bags; for Charge 7, you discarded the bag marked 'Chge 8' and loaded the other seven; for Charge 6 you discarded the 'Chge 8' and 'Chge 7' bags and so on. Now, here’s the thing: with no cartridge case, you need a different method of obturation. Generally, the breech is now sealed by having a mushroom-shaped centre-piece in the breech closure which, on firing, is pushed back by the chamber gas pressure, squashing a flexible pad (a bit like an O-ring) against the side walls of the chamber and preventing the rearward escape of gas. Just about the only way of doing this is to close the breech by screwing in a ’breech block’, rather than simply sliding it in behind a cartridge case.

The latter method was developed earlier and was, at first, the only satisfactory way of designing an artillery piece which could be loaded from the back not the front. Hence the Brits called such weapons ‘Breech Loading’ or ‘BL’ to distinguish the weapons from muzzle-loaders (‘ML’). Obturation by cartridge case was developed later and such weapons were termed ‘Quick Firing’ or ‘QF’, simply because initially they generally fired fixed rounds and were therefore quicker to reload. So, although all guns and howitzers since the late 1800s have been loaded via the breech, only some of them are BL pieces, according to the British.

And all that was leading up to this…

Sliding-block (generally QF) breeches tend to look squarish, while screw (generally BL) breeches usually look rounded or cylindrical. Unless that’s a tool box partly obscuring our view of the breech in the original photos, the breech of that French gun looks pretty squarish to me. It should be noted that the French and Germans tended to use a cartridge case even with separate-loading ammunition in larger guns and so sliding blocks are not uncommon in their larger-calibre pieces (see for example the photo in Knotty’s Post #11, above, of the piece at Fort de la Pompelle. I don’t know much about French WW 1 artillery, but is that a Canon de 155 GPF mle 1917?)

 

The piece in the original photos appears to me to be shorter than the one at Pompelle and their construction appears different. The latter has distinct shoulders marking the different tubes while the former appears to have a smooth profile from breech to muzzle.

 

Bored, yet?

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I should have added that the British 13- and 18 pdrs were also QF equipments with screw breeches, so this combination was less common but definitely not all that rare.

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On 29/07/2020 at 13:51, Rod Burgess said:

Back on topic, with another interminable history lesson. ... Bored, yet?

 

Not at all, Rod, two very informative posts and much appreciated. My experience of the high angle/low angle trick was at buoys out at sea, firing from the Lulworth tank range through the Arish Mell gap - spectacular!

 

Richard

Edited by Old Forge
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  • 7 months later...

DuckDuckGo search sent me here...

 

It's a Canon de 145mm L Mle 1916 Ruelle-Saint-Chamond. The barrel is L/47.5 (6.88m) long. It started out as a 138mm Mle 1910 L/55 Naval gun but was

bored out to 145mm. It's unusual to see the gun being transported as two loads, more usual was to use a limber and withdraw the barrel and move it as one 13ton load.

The Saint-Chamond gun along with the 155mm GPF gun formed the striking power of the RALTs (Regiment l'Artillerie Lourdes a Tracteur) which relied on vehicle transport

(wheeled and tracked) to move the guns. British Army artillery didn't really catch up with the RALTs until the late 30s.

 

Regards,

 

Charlie

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On 06/07/2020 at 18:26, Knotty said:

Is that the same as the one outside of Ft Pompelle?

3EF27566-0907-48DC-9A50-72E6108AC7DA.jpeg

That's a lash up of a Canon de 155mm L Mle 1917 GPF carriage and limber with a modern gun barrel - the identity of which escapes my memory at the moment

 

Charlie

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Hi Charlie

Welcome to the Forum, I would like to know what it is made up from, looks the part😁

 

John

Edited by Knotty
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Looked it up - it is apparently a 105mm gun barrel from an AMX-30 tank

 

The gun in the original query could be one of the 12 145mm L/55 Mle 1910 guns made by Saint_Chamond. The barrel is about a meter longer in the

L/55 and there are differences in the carriage but the image isn't good enough to resolved those.

 

Charlie

 

 

Edited by CharlieLII
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So it’s not even 155mm, I’m sorry and disappointed that it’s a ‘fake’, but never mind it does somehow portray what was there at the time, thanks for looking.

 

John

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13 minutes ago, Knotty said:

So it’s not even 155mm, I’m sorry and disappointed that it’s a ‘fake’, but never mind it does somehow portray what was there at the time, thanks for looking.

 

John

I'm just glad someone sorted it out - it certainly confused me. No wonder it looks so weird. The double-baffle muzzle brake and tiny recoil cylinder look way beyond WW1 build. :D

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