Exploded Shell ID?

[S Kelly]

It measures to be a 75mm.  The grooves where the driving band would be are similar to some US rounds I have seen.  But, the curious thing is the cap at the base.  It appears to be copper or brass.   Is it some sort of gas check?  It seems too small for that.  Any ID ideas?  

[Terry_Reeves]

S Kellly

I think you are talking about the driving band which engaged in the rifling of the barrel which produced spin.

TR

 

Edited 17 October , 2021 by Terry_Reeves

[S Kelly]

3 minutes ago, Terry_Reeves said:

S Kellly

I think you are talking about the driving band.

TR

 

3 minutes ago, Terry_Reeves said:

S Kellly

I think you are talking about the driving band which engaged in the rifling of the barrel.

TR

No, the curious piece is the metal disc on the butt of the shell.  The driving band was detached when the shell exploded and is long gone.  Can you see the photo?   The disc is roughly 4 cm in diameter.  

[Terry_Reeves]

27 minutes ago, S Kelly said:

 

No, the curious piece is the metal disc on the butt of the shell.  The driving band was detached when the shell exploded and is long gone.  Can you see the photo?   The disc is roughly 4 cm in diameter.  

In which case I have no idea .

TR

[onesearch]

Looks like a sealing or blanking disc for some purpose or another... what can be seen from inside the shell? Does it have a structure or hole down towards the disc; is the disc Is it even visible?

Also wondering if there is any chance of it being post WW1, as I think some later shells had something similar.

 

Interesting symmetry in its burst state ....

[MikB]

1 hour ago, onesearch said:

Looks like a sealing or blanking disc for some purpose or another... what can be seen from inside the shell? Does it have a structure or hole down towards the disc; is the disc Is it even visible?

Also wondering if there is any chance of it being post WW1, as I think some later shells had something similar.

 

Interesting symmetry in its burst state ....

It might have been a shell body that could have been finished in various configurations, some of which - not this one - included a tracer at the base; and we're seeing a blanking plug inserted to cover the hole. Or it might cover the hole for a base fuze - again, not used on this variant. 

[onesearch]

7 hours ago, MikB said:

It might have been a shell body that could have been finished in various configurations, some of which - not this one - included a tracer at the base; and we're seeing a blanking plug inserted to cover the hole. Or it might cover the hole for a base fuze - again, not used on this variant. 

Looks like we might be thinking  along similar lines.

I am beginning to think it might be the sealing plug to a base charge but have no hard evidence to support if, but it's a strong suspicion. The idea of a location for a base fuse has possibilities too.

[ServiceRumDiluted]

Apparently the French had some issues with premature detonations while the shell was in the barrel caused by propellant gases reaching the charge through fissures in the crudely made shell base. They temporarily solved this by using higher grade material plates in the base until manufacturing methods improved. I don't recall where I learned this, but if I can find the source I'll let you know.

Edited 21 October , 2021 by ServiceRumDiluted

[onesearch]

4 hours ago, ServiceRumDiluted said:

Apparently the French had some issues with premature detonations while the shell was in the barrel caused by propellant gases reaching the charge through fissures in the crudely made shell base. They temporarily solved this by using higher grade material plates in the base until manufacturing methods improved. I don't recall where I learned this, but if I can find the source I'll let you know.

It would be interesting to see a picture of a known example to see how the two compare. Not sure what the wall thickness of the pictured example is but I wonder if a larger diameter disc might be more in keeping / effective in maintaining the 'firebreak' between the shell head the propellant charge? Don't know...but I'd be keen to know.

Also wonder what a barrel might look like after a premature detonation.

[awjdthumper]

I think this is just a common pointed HE shell (in British parlance) which used a base fuse. These sometimes had a brass base cover.  This one may have used a gun powder bursting charge resulting in the splayed form for the remains of the rear end of the shell.

[o j kirby]

I have a similar shell. The base is just under 75mm although not measured scientifically. About one third of the shell remains after detonation, and although this part is bent, my tape measure gives me a rough 26.5 cm up to the top. Inner threads tells me that a nose cap had been fitted. On the base is partially peeled thin metal disc which appears to be iron or steel. My example was picked up near Verdun back in the 80's. If I can get decent light I will try to photograph the item and post it in due course.

Owain.

[awjdthumper]

To confirm whether this is a base fused shell, it should be possible to see the remains of the brass fuse poking up into the inside. If the bottom of the cavity is rusted steel then it is nose fused.

[S Kelly]

Adding a picture of the interior.  Solid base from the inside.  Thickness of the base is right at 1.5cm

[MikB]

More than likely a tracer pocket blanking plug then, which might tend to date it WW2 or later. I wouldn't *think* the ductile casing would be typical of WW1 either, but could stand corrected on that.

[onesearch]

Thanks for posting a second picture showing the internal view.  To me I can't  see any visible gallery, thread or structure between the external base & the internal base of the shell. So it looks more like an external pocket with a sealing cap.

As Mike B posted above  & my post earlier on could it be a post WW1 item, anyone else thinking this might be a possibility?

[14276265]

The shell is a WWI French 75mm chemical or smoke fill. The body petalling is a common result of the burster charge on the thin body walls. The brass base disc (often also used on French 75 HE shell) sits in a milled recess to prevent piping - the hot high pressure propellant gases acting parallel to the grain of the forged steel penetrating the relatively thin centre of the base.

[S Kelly]

Thank you to all  for your posts….especially this last one.  This has been very helpful.  14276265, do you have any more information? Any photos of other examples?

[14276265]

I have very little on French ammunition, but herewith a drawing of the method of filling of British medium natures such as 4.7" and 60pr gun. The layouts, chemicals and principles of operation are similar for French and British shell (which were usually based on HE bodies) so the drawing gives an idea of the internals: the burster charge, the smoke pot for indicating fall of shell, and gas plug at the base. The French 75mm were much smaller rounds and may not have used a smoke pot; the payload was small but they were fired in large quantities.

In the early 1990s in the old German lines below Mort Homme at Verdun, there were dozens of these petalled bodies just sticking out of the ground over about 200m of the French forestry commission track. A typical 75 chemical payload at the battle of Verdun was phosgene, so I imagine the German lines at at this point had taken a bit of a pasting with phosgene. A photo of another example of petalled shell attached.

.

Edited 24 October , 2021 by 14276265

[onesearch]

Great reply & explanation, the drawings are interesting on their own but the explanation& identification is very very helpful & nice to know