I thought the statement that the entrance wound in the back of Kennedy's skull being only 6 mm in diameter was compelling. The Carcano rifle rounds were 6.5 mm before they were fired, but the article claims they expand to 6.75 mm from the force of the charge propelling them.
How does a 6.75 mm round leave a 6 mm hole?
On the other hand, the Secret Service agent behind Kennedy had an AR 15 which fires 5.6 mm rounds, and which would then conceivably leave a 6 mm hole.
Seems like that would be a pretty compelling bit of evidence that Oswald didn't make the killing head shot.
Measurements might not have been precise. That doesn’t bother me. If one believes the head shot came from behind then Oswald likely did it.
My problem is I have never been able to watch the Zapruder film and feel convinced the shot came from behind based on how his head reels backwards. Perhaps the car was speeding up at the exact moment the head shot was delivered. Dunno.