You should try not to move the camera, grunt, and his hand that much. When watching people shoot guns in movies and videos, you can see that the movement of the person who is shooting the gun only moves a little bit, while the arm holding the gun moves like a small wave in the ocean. the hand moves up a little and then goes down like as if the person was slowly putting down a very full cup of water but a bit faster.
also just don’t move the camera at all