Hi all. I have had this a while and am trying to find something out about it. All I know for sure is that it is a 20mm shell case. There are no markings on it at all. The closest thing to it I have found thus far is the ww2 German 20mm (see pic below) although if it were German I would have expected it to be marked? Any info would be fantastic. Cheers.
Oh and measurements are 20x100mm