Shot shell/ igniter / id

A reader from my website asked the manufacturer of this all brass shell casing that appears to be about 4 bore. I believe it is not a shotshell as such but a bomb or mortar type of cartridge. Can anyone confirm and as well shed some light on the manufacturer.

Thanks Gents

I think like you that you can rule out the shotshell thoughts.
But another possibility is a flare case.

No idea on the manufacturer.

Regards René

This is a German 26.5mm flare gun case made by AEG (which is well known today) and was made for Hermann Weiffenbach (an arms dealer if I remember correctly).

Source: Thielbörger book on European flare gun cartridges.

Thanks, this is what I was needing. Appreciate it.