Animation: how to get bone to control another nonparented object?

I’ve made a model of a character and a weapon in separated objects in blender. I’ve done the animation for the character first and thought that I could make a separated animation for the gun then sort of snap them to the hand which moves all the time. It seems that I couldn’t find a way to do that. Is it possible? and If it is then how. Thank you so much in advance! PS. here is the Pic so you can understand what I mean.


Welcome to the forum,
This section is for modeler, so next time read before posting.

Did you rig your model? If not then it will be difficult for the gun to follow the hand because you don’t have enough info on the hand.
If the character is rigged then you can just parent an empty to the hand bone (so add empty to the location of that bone, then select the empty and select the bone, selection order is very important, ctrl+p -> keep transform) and select gun parent it to the empty (so select the gun and select the empty ctrl+p -> keep transform).

To Mod: He is a newbie do you mind to change the thread to the right place please.