The meaning of the C-30-7.65 is simply Caliber (Calibro) .30" - 7.65 mm. These are inside-primed cartridges. That cartridge is the 7.65 Pickert, a revolver version of the 7.65 mm Browning Automatic cartridge. Since the original Browning round is semi-rimmed, I believe that ehy will work in the revolvers as well as the inside-primed Pickert round. Only Fiocchi made the Pickert. There is a 6.35 mm Version also, but while the 7.65 Pickert is common, you seldom see the 6.35 mm version, at least in the USA. By the way, some sources have said the “C” on the Pickert headstamps stands for “Cartuccia” (cartridge, singular - “Cartucce” in plural), and I have no documentation to dispute that, but I believe “Calibro” is more logical.
I don’t know anything in particular about the revolver cartridge next to it.