18mm cartridge found in the back yard - what is it?

This turned up in the back yard and appears to be quite old. It has no markings

18mm x 38mm

Hell it may not even be a cartridge but a plumbing item or some such curio, but I would like to know!!


Welcome to the Forum!

Nickel plated brass, odd “rim” and rusted steel object in the “primer pocket” (?).

Does the rusted steel object extend into the “case”?

Hmmmmm! I don’t know!

The only thing cartridge wise remotely close that I can find is the French 18x35 R Tabatière Rifle Mod. 1867 cartridge but the case wall is paper/cardboard. All this means is I still don’t know!!!