Hello everyone.
Im creating a fps and im working on the animations, but i dont know how to make the recharging animations (and some others) as I have to different game objects, one for the hands and other for the gun. Do I have to create one animation for everyone and play them together? Or is there a way to make only one animation with 2 different game objects?

You can make just one animation for the hand with and a empty game object (know as placeholder) instead of the gun. Add the gun as child of the placeholder and it’ll move together when you play it.