in addition to the danish cartridges M.1880 (9x18R) and M.1891 (9x17R) - both close to the .380 Short CF - was a blank round in service there.
Sources say that they are 23 mm long, case mouth rose-crimped over a white cardbord-plate, no headstamp.
A picture (poorly no front-pic of the crimp available): vaabenhistoriskselskab.dk/me … 233029.jpg
From the danish blanks this one here differs in the cardboard colour (red) and the crimp-folds. But it was called danish …
So what is it: a danish blank, a .380 ‘something’ blank (commercial?) or something complete different?