UE4 - Just one difference in Class?!?

I work on a shooter game. And in the game you can drop en buy the same gun.

So in the world there could be 2 the same "BP_Rifle"s and both are children classes of “BP_MasterWeapon”.

When i first shoot and drop it then buy a new one i still want the weapons to remain there amount of bullets.
I have a idea how i can do that but then i need one thing that is different in every actor , so something that shows that every actor has his own idendity.

Does someone know something like this? or have another idea of how i could do this system

please tell me.