The “second gunman theory” is not much of a theory, seeing as it based on ballistics as taught by grade B western films. This clip, taken from Penn & Teller’s Bullsh*it! series aired on Showtime (S03E03), illustrates how bullets really behave when penetrating a spheroid object (a human skull or a melon) filled with a mostly-liquid pulpy mass (brain matter or melon goo). The conspiracy dolts (And those of you who adhere to conspiracy theories about the JFK murder are dolts, don’t bother to deny it. Those of you who write books promoting conspiracy theories are not dolts, you are clever frauds.) say that a human head will be driven forward by a shot from behind, and therefore, since JFK’s head goes backwards, the kill shot came from the front. Not true, as shown by this simple experiment. (Why don’t idiots do experiments? Easy, they haven’t the skill or the discipline. Also experiments tend to debunk myths, can’t tolerate that!) When an FMJ bullet enters a skull it penetrates very easily and leaves a small wound on the surface, transferring little energy to the head. When it exits the other side it creates a much larger wound. The brain matter jets out the exit wound at high speed. Like all jets it exerts a thrust on the head, driving it in the opposite direction of the bullet. This is the 3rd Law in action. Do you doubt me? Try the P&T demo yourself. Use a rifle with FMJ ammo and shoot at a melon or something else with a semi-sold interior. It will move backward relative to the path of the bullet every time. Don’t shoot something hollow, which is a poor analog for a head with brains in it, because the results will be inconsistent.