If the coin is identical to what you googled then you have probably as much information as you will get. Chinese "coins" vary a lot. There are a lot of so called coins that were cast as good luck charms after arrival here. I don't know how you identify them but I might assume that they only have writing on one side. I am only assuming this and could be completely wrong.
As for the cartridge, it is what is stamped on the bottom, a 9mm Luger cartridge. It would have been dropped after WW2 most likely. Maybe even by Adolph Hitler himself or one of his cronies that left Germany to escape to Argentina or Brazil. Widely available and probably not worth anything other than a goldfield memento. So what do you do with it? DO NOT FIRE IT. See if the police will take it and dispose of it.
Regards Axtyr.