Character collision issues

Hello, I have been trying to work on character collision to determine what part of the character the bullet it hits (for an FPS Project). However, it doesn’t work properly when using animations or using an aim offset. This is my physics asset:

as you can see I have 4 spheres in the head, all of them inside the mesh. But take a look in game:

If I shoot at that location, it hit’s the head. That shouldn’t happen. Any ideas how to fix this problem?