I have this unfired shotshell case (unloaded by me).Its measures are close to those of the 9 mm flobert shotshell with paper case,but it is CF.
It was turned from solid brass and it has no headstamps.
I think it could be an experimental round to convert some 9 mm flobert guns from RF to CF
However it could be everything else,I have no info about this round
rim diam: 10,22 mm
base diam:8,67 mm
neck diam:8,22 mm
inside neck diam:6,27 mm
case lenght:39,57 mm