Combining weapon animation and character animation

Hi everybody, my first question here!

In a 3d game project I have a character firing with a sling (not a slingshot, but an ancient sling!). It works great but I’d like to make the sling rotate in his hand during the action (2 animator state transitions, 6-7 seconds). The action starting parameter is an Int (AttackID=11).

Any idea how to achieve this?

Thank very much!

Perhaps, Animation Layer are what you need: Unity - Manual: Animation Layers