I am still looking for information regarding this cartridge. The #9 shot load of the top specimen matches a cartridge (possibly SFM manufactured) that was listed in an old Buttweiler catalogue (RTB VI.3.250) designated as the .50 French Remington Pistol, but apart from that I have not been able to find any other information. It may even be likely that is is a shot load made from an old 11x59R French Gras case, but again, no proof yet. In the ECRA database is a cartridge listed as the 15.24 x 28.4R Montenegrin Krnka Carbine. It is also the same one listed in Hoyem 2, p.197 (CFR185). The ball round at the bottom however has a case length of 23.3mm and a bullet diameter of 13.37 (.526″), so although there is some resemblance, it is not the same. The bottom specimen resembles a 500 Tranter.