Look Jackie Kennedy’s reaction in the Zapruder film, first thing she does is try to retrieve his brains from the trunk of the car, which supports a shot from the front right aka Grassy Knoll or somewhere close
Yeah, I’ve seen it. The question becomes, does the brain material have momentum imparted to it by a bullet, or does it become independent matter, which the limo then drives out from under? The relative motion of brain/ head would be the same in either case, I would think.