Bill Woodin obtained this cartridge quite a few years ago. It stumped me and pretty well stumped him.
It looks like it was originally a lacquered steel case round headstamped with a unusual “G” (with a pointed bottom) and three stars. The bullet looks like a 9mm P08 which has been fired. Excuse the poor photos. They were taken in a dark area with my I phone.
Bill has taken the measurements on this round (top on the list below) and on the three most likely original candidates for the case. It looks most likely that it was originally a 9mm Browning Long case (bottom on the list below).
The trouble is that Bill doesn’t recall of a steel case Browning Long round with any headstamp. Nor does he, or I, recall a lacquered steel case with this headstamp in any pistol round of about 9mm!
The headstamp and particularly the strange “G” are vaguely familiar to me, but I don’t recall where I have seen one.
If anyone has any thoughts on this they would be greatly appreciated.