I found this cartridge in a little village (in a garden right next to an old house) near Budapest, a few centimeters below the surface. I suspect it is from WWII as three armies operated in the area.
I think it could be a 7.62×25mm Tokarev cartridge, a cartridge used for the Tokarev TT-33 pistol and various submachine guns the Russians used during the war. However, perhaps it is a 7.63×25mm cartridge, very similar to the Russian just described cartridge, used for the German Mauser C96 pistol.
I could not discern writing on its base, though maybe it had worn off over time.
I measured it:
Here are its dimensions:
35 mm total length
the case is 25 mm long
the base is 9 mm or 9.20 mm wide