German heavy gun shell case Ponte Magdeburg Juli 1917 No. 134

[DavidFinch]

I have inherited a shell case with the markings noted in the title of this message. 
 

I’m interested in any information about the casing.

[AndyBsk]

Should be probably Polte Magdeburg.

[Spaceman]

It would be interesting to know the diameter of the open end of the case to enable the German artillery piece to be identified. It looks at bit long for a 15 cm sFH (heavy field howitzer) and may be from a 21 cm Morser (the Germans called this large size a mortar rather than a howitzer for some reason).

[DavidFinch]

220mm at the open end. - hence why I refer to it as a “heavy gun”.

 

yes, it should have been “Polte”

 

it also has “SP40” under the Magdeburg impression.

It has clearly been cut down at some point - a real shame as it is too shallow for use as an umbrella stand. Now I’ve cleaned it, any provenance has been wiped away too!

hope this helps

[Alan24]

I have a similar one which measures 110mm at the open end and 93mm high, dated April 1917 and has the mark Sp406. 

I always believed it to be for a Krupp 10.5cm gun. 

[peregrinvs]

It looks like a normal length 21cm Mörser case to me. Commonly recycled as waste paper baskets.

Edited 19 November , 2023 by peregrinvs

[Spaceman]

I agree. If so, the height should be 233 mm and the base diameter 236 mm?

[MikB]

2 hours ago, Alan24 said:

I have a similar one which measures 110mm at the open end and 93mm high, dated April 1917 and has the mark Sp406. 

I always believed it to be for a Krupp 10.5cm gun. 

That one'll likely be for the leichter Feldhaubitze 98/09, originally by Rheinmetall, later redesigned by Krupp. I have a similar case from 1916 - I use it to hold my Swiss files in the workshop... 

[DavidFinch]

Spaceman - yes! 233mm high and the backseat diameter is probably 236mm.

do you know what cannon this would have never made for, and where on the Western Front these guns were being used (late 1917 onwards)?

[Spaceman]

The Germans started the war with the 21 cm Morser 10 that was basically a similar calibre to an 8-inch howitzer with a range of 9,400 m. The shell weighed 114 kg. Unlike low angle trajectory guns/cannons, this type of howitzer used a relatively small propellant which is why the shell case appears to be quite short. As with most of the German artillery, everything was updated in 1916, in this case, to a longer barrel 21 cm Morser 16 to increase the range by a couple of km. Therefore, if this case dates from WW1, it may have been fired by either the 10 or the 16.

Edited 19 November , 2023 by Spaceman

[DavidFinch]

Interesting!

We’re the Morsers (10 or16) used throughout the western front, or were they more localised?

[Chasemuseum]

Widely used all over the place. They were part of "Corps/Army" artillery rather than "Divisional" artillery so were used where they were needed, rather than being tied as a regiment within an infantry Division. 

Britain initially deployed heavy artillery within the Division, but fairly quickly followed the German lead and reallocated them up the army structure (I cannot give the actual date, but it has been previously posted on the forum).

The shell case is only a gas seal for the breach, it does not need to be as long as the propellant charge. The barrel is brought to a horizontal position. The shell is rammed through the breach hard enough for the driving band to engage in the rifling. The propellant bags (number varies for range) are loaded and the cartridge case, the breach is closed and the barrel elevated to the precalculated angle verified with a clinometer and prismatic optical sight adjusted to the predetermined angle is aimed at an aiming post about 20m away. Then the gun can be fired.  

 

All fairly straight forward - except that precision indirect fire was a new technology since the Boer War, and resulted in a dramatic change to the operation of the battlefield. The artillery deployment and fire of Colenso and Ladysmith were ancient history compared to WW1. Like the jump from a landline telephone to a modern I-phone, or a solid tyre lorry to a modern Kenworth B-double.

[Spaceman]

The interesting thing about German WW1 artillery technology was that they used brass shell cases in all their artillery pieces to achieve obturation - that is, the means for sealing the breech against escaping propellant gases. In contrast, the British and French used bagged cartridges in their larger artillery pieces (6 inches and above). The trade off was that bagged charges needed complicated interrupted screw type breeches to provide obturation but the bagged cartridges they used were relatively cheap. In contrast, the German use of metallic cartridges to provide obturation was expensive in terms of ammunition cost but allowed them to use less complicated sliding block breeches.

The 21 cm Morsers were basically employed in destroying strong points or fortifications using their large shells.

[MikB]

On 19/11/2023 at 23:02, Chasemuseum said:

...

The shell case is only a gas seal for the breach, it does not need to be as long as the propellant charge. The barrel is brought to a horizontal position. The shell is rammed through the breach hard enough for the driving band to engage in the rifling. The propellant bags (number varies for range) are loaded and the cartridge case, the breach is closed and the barrel elevated to the precalculated angle verified with a clinometer and prismatic optical sight adjusted to the predetermined angle is aimed at an aiming post about 20m away. Then the gun can be fired.  

...

 

That's true. I once had a SMLE with a loose enough chamber to cause occasional case head separations. These occurred only a few millimetres ahead of the web where the base of the powder chamber joined the tapered body, but there was never any obvious backward leakage of propellant gases - in fact I usually was only aware of the event when I couldn't feed the next round because of the hollow body left in the chamber.

In the case of artillery, the risk associated with a short case - or uncased bagged charges - might be that if the shell's driving band wasn't firmly enough wrung into the rifling lead-in to hold it in position when elevated, the round might fall back and crush the charge. This would usually result in a faster propellant burn and very possibly a dangerously-high early pressure peak. Very large-calibre projectiles were probably so heavy that a normal-thickness brass case wouldn't be able to prevent that, but in the smaller and medium sizes a full-length case might mave a safety value.

[Chasemuseum]

Having the shell fall back is thought to be even more dangerous, with the shell never correctly engaging with the barrel and suffering a premature explosion. 

 

One of the "Paris Guns" is believed to have been destroyed by such an incident.

[Spaceman]

Shell fall back is potentially very dangerous with one effect being that you can get significant propellant gas blow by until the driving band hits the rifling again and this can result in shells falling short and endangering friendly forces. However, I'm not sure how big an issue this is in practice?

[trajan]

On 19/11/2023 at 18:31, DavidFinch said:

it also has “SP40” under the Magdeburg impression.

Spandau Armoury inspector's mark.