How do i make a genrade dissaper once i used all of them?

I am makeing a battle royale style game and I can’t figure out how I would make a genrade be throwen from my hand and not replaced with anothor on whe there is no more genrades in the invetory. To simplify my question how do I make a generads weapon system like in pubg where the genrade is thrown and is not replaced by one if there you don’t have any left. If you are able to help can you please send a picture of how the blueprints would look. Thanks in advanced.