CBS and Dan Rather successfully reproduced the shooting by putting marksmen on a tower of the same height, firing at a moving target with the same rifle. Several hit with two bullets; one hit with three bullets. All fired three rounds within six seconds.
Regarding the "magic bullet", PBS showed how the path lines up when you correctly locate Connelly in the jump seat, which was lower and offset, turn Connelly slightly in his seat, and have JFK leaning forward a bit, as he was known to do because of back pain. The magic bullet trajectory isn't very magical.
The path of the bullet isn't the most eyebrow raising to me because bullets take some wonky paths when they collide with bodies. What's a bit concerning is after taking that wonky path, hitting ribs and wrist bones, the bullet came out practically un-deformed and in relatively pristine condition.
The most plausible explanation I've heard is that after going through JFK's neck and most of Connally's chest without striking bone, it was significantly slowed down so that when it hit Connally's rib and wrist, it was with less than full force so the copper jacket held up better. Warren Commission tests on comparable bullets showed them staying relatively intact even when striking solid wood.
This is a situation, I think, where people's intuitions don't line up well the reality of full metal jacket ammunition, which by design is supposed to deform or fragment less than softer slugs.
My favorite theory is that the killing blow was actually done by the secret service, but not because they had a grand scheme to kill him and blame all on Lee, but because the senior members of the SC were hangover and gave rifle duty to a junior that had just completed training. During the commotion of the first shots, he accidentally fired from the second vehicle when it accelerated and killed the US president.
Video of their tests: https://www.youtube.com/watch?v=ghmY6HmR4fs
Regarding the "magic bullet", PBS showed how the path lines up when you correctly locate Connelly in the jump seat, which was lower and offset, turn Connelly slightly in his seat, and have JFK leaning forward a bit, as he was known to do because of back pain. The magic bullet trajectory isn't very magical.
From this episode of Nova, IIRC: https://www.pbs.org/wgbh/nova/video/cold-case-jfk/