detach body parts

Hi folks!

It sounds a bit crude but what I need is a way to detach bodyparts when I shoot them.

Firstly look at my screenshot

This is the goal I want to reach, on the left you can see the entire body and on the right the mutilated body and the arm.

To have a good effect I want to leave the common bone (upperarm) in both elements, so I started do creare a clone of the arm-bone-system but then I need to reskin the arm mesh to the new cloned bones.

I tried to assign new bones to the arm mesh with GetComponent(SkinnedMeshRenderer).bones but it doesn't work :(...

Any idea? Maybe I need to go with bind poses?

Thanks a lot :)