Arlen Specter did not propose the "magic bullet theory"

[William Seger]

16. It's the two frames immediately before and after the hit

... and what it shows is that the head snapped forward immediately after the hit, not "back and to the left." Several people have done precise analyses (see the Google search link) that came up with about 2 to 2.5 inches forward. As the bullet traversed the head, it slowed down, and by the law of momentum conservation, the momentum that the bullet lost by slowing down was instantaneously transferred to the head. The important point is that the bullet transferred momentum to the head only while it was in contact with the head. Since it is already long gone by that second frame, the bullet cannot impart any more momentum to the head after that second frame. The "back and to the left" motion, however, starts two frames after the hit and it accelerates for several frames, and neither of those facts can be explained by momentum transfer from the bullet. Therefore, that forward head snap unambiguously implies that the shot came from behind.