My mag won't move in my reload animation

My mag won’t move in my reload animation. When I play it the gun moves as it should but when the hand goes to take the mag the mag doesn’t move. Can anyone help if so that would be amazing?

More info needed. Is the mag animated? How is the arms/hands animated, in Unity or external animation imported? What is your setup. Was the gun animated with the arms externally and imported? Was the mag animated? Is the gun is parented to the hands, and the mag parented to the gun?
The mag should switch parents during the animation from its original parent to the left hand, unless the mag is animated during the animation.

More info needed.