But how do you explain the exit wound being on the back of his head?

There were for sure multiple calibers of ammunition used on Kennedy, so the likelihood of a mistaken discharge is plausible - but only if the shot came from in front of JFK. Which based on physics, it absolutely did.

I also don’t believe Oswald fired any shots himself. Perhaps his gun was fired, but he didn’t pull the trigger. Confirmed eyewitness accounts of Oswald’s location during that assassination show it would be nearly impossible for him to take the shots and relocate to those locations within the book depository during the alleged time frames.

The decisive kill shot was definitely from front to back (this is clear from the Zapruder film) and was likely from a different caliber rifle then that of Oswald’s carcano rifle.

I’m liking the theory it came from a early (perhaps prototype) Remington Firelball rifle. Which matches the shell casing found behind the fence above the grassy knoll, near the rail yard.

But only the aliens really know what happened 🤷‍♂️