French trench art

[Louis]

I recently found a nice bit of trench art near my hometown in the south of france, it’s not the most detailed piece in the world but I like to imagine all the work that the soldier put into it. It has a few stamps on it (clockwise):
St
308
1917
67%Cu (copper content?)
HI31(????)
DEZ
I think ST DEZ is the place of manufacture but other than that everything else apart from 1917 I have no idea of the significance.

 

[Lars13]

Hi Louis,
Nice find, congratulations.
The “DEZ” stands for Dezember, so the shell was made by the Germans in December 1917.
The 67% Cu is indeed the copper content; the Germans had a shortage of copper and were using different alloys, and even steel!
The other letters indicate where the shell was made, and probably also what gun it was for, but I’m traveling so I don’t have access to my sources now.
Regards, Lars

 

[Sandmann]

Unfortunately I don’t know the stamp regulatuins for granates but as a German I agree with Lars that DEZ stands for Dezember.