I recently acquired another 20x139 Case that I believe is South African like the other one I had, which I still have never had a certain ID on.
This case is a gloss black lacquered steel case headstamped “20 mm A 94 SE”. I thought the “A” marking on the case could be Armscor/PMP.
It has a brass screw-in primer with three semi-circular tool holes. The primer is marked "DM64 320 B 94.
Can anyone say for certain who the manufacturer is?