The Wizard made this NBC gif, and what jumped out at me is Oswald's movements, and his reversal of movement. Upon being shot, he first goes forward and down, which makes sense. But then, that movement gets reversed, and really by 180 degrees. He stops going forward, and it means that he literally had to stop because you can't reverse the direction of your velocity without stopping. And then, he starts going backward- the opposite way.
The bullet didn't impart any momentum to his body at all. It just cut through him. But, if it could impart momentum, it wouldn't be forward or back because he was hit in the side. So, the falling forward and down would have to be attributed just to him not being able to stand any more because he was shot, and most or all of the work involved in that would be due to gravity. When your energy is gone, gravity is all that's left. But, the veering backward? That was Oswald. His muscles did that, but how could they if his major blood vessels were blown apart? This is why I keep telling you that he wasn't really shot. He would not have been to do that if he was really shot. And that means that even the forward and down movement was due to him and not to gravity. He was faking it.