Fps Reload animation help please

Hello :)

I'm currently making an fps game but since its online, my character is a full-body model made in blender (with fingers kinematics), so I just implemented my first gun but I don't get how am I supposed to animate the reload or aiming animation since my arms and the gun are not the same objects (I animate in blender), I tried having 2 separate animations in the gun and character and playing them at the same time but I made som little changes at my character (in his hands) and that messed up the whole animation, I'm sure there should be a better way to address this. Can you help me with this, please?