The front right of his head exploded, which pushed the head backwards. It's all on the zapruder film, very clearly. The front of his head explodes. There is actually a second video from across the plaza where you can see the exact same spray pattern as in the zapruder film.
There's no "magic bullet," when you line Kennedy and Connally up correctly. The path is a straight line and the bullet never hit any bone until Connally's wrist, where it was significantly slowed down. And lead was discharged from the back of the casing and the bullet is deformed.
The JFK assassination committee in the 70s absolutely did not overturn the conclusion of the warren commission. That tells me you didn't even read it. They concluded a conspiracy solely on an audio recording that was later shown to be from a different time period than the assassination. The committee otherwise pretty much confirmed the conclusions from the warren commission.
Here's my conclusion after reviewing both sides very thoroughly: there is no evidence that anyone other than Oswald shot the president.
Stabilized zapruder film: https://www.youtube.com/watch?v=102YMXW3BxA
Nix film of assassination (no rear exit wound): https://www.youtube.com/watch?v=jMxiGj9bo0U
"Magic" bullet theory explanation (and correct alignment): http://dyingwords.net/the-magic-bullet-in-the-jfk-assassinat...