A recent discussion with photos on the Reibert Info Forum by forum member “tr30801” concerning some early 1900s 7.62x54mmR cartridge cases having single flash-hole primer pockets, photos shown below:
It seems these case were produced at the Lugansk cartridge plant in the years 1901, 1902 and possibly 1903. Typically 7.62x54mmR cases have primer pockets with 2 flash-holes.
This resembles the Georg Roth patent design using a single flash-hole primer pocket & Berdan primer.
Comments, info are most welcomed.