However, as John Mytton said on another thread, the bullet would have been greatly slowed down after having passed through Kennedy's neck/upper torso and Connelly's torso and would have only slapped into his wrist bone.
Hi Jim, as I've just pointed out to Tom, the idea that a tumbling bullet that had slowed down as it smashed a wrist bone, would sustain damage similar to that present on CE399, is made up. No one has ever produced any evidence to demonstrate this claim. It is just something that gets repeated so often people assume it's some kind of fact.
I believe the bullet that passed through JFK and JBC fragmented when it shattered JBC's wrist bone. When we look at the X-ray below and see how the metal fragments are scattered throughout the wound it seems obvious, to me at least, that this spread of fragments is caused by a bullet fragmenting and some of the smaller fragments being blown into the wound.

How could CE399 spread fragments throughout the wound like this?
More importantly, how could a bullet, supposedly rotating at incredibly high speed, pass directly through the wrist bone without leaving any evidence of doing so. The bullet didn't glance the wrist bone or "sideswipe" it - it passed directly through the bone.
This is what a wrist bone looks like when a bullet has passed through it:

It doesn't matter what speed the bullet is traveling, it has to make it's way through the bone and, therefore, leave a hole as it passes through. There is absolutely no evidence that a rotating bullet passed through JBC's wrist bone.
I vaguely remember someone trying to argue that the bullet passed through JBC's wrist bone just quick enough to smash it to pieces but slow enough so that after it had made it's way through to the other side the pieces came back together again!! The mental gymnastics some people employ to "win a point" never ceases to amaze me
Final note on this - the idea that the bullet was tumbling was invented by Dr Gregory to explain the only way it was possible for CE399 to leave metal fragments in a wound. The only exposed part of CE399 from which metal fragments could have come is at the base, therefore, if the bullet was CE399 it must have entered the wound base-first, therefore it had to be rotating, therefore CE399 is a tumbling bullet. What is odd with this is that it seems to have stopped tumbling when it hit JBC's wrist because it entered JBC's thigh base-first as well as entering the wrist base-first. How is this possible if the bullet is tumbling?
Also Dan, how do you reply to what John said here:
"Another interesting observation is why would the conspirators plant a whole bullet? In another thread Dan rightfully points out that a full speed bullet that strikes bone will radically deform and at this early stage when Tomlinson discovered CE399 as it rolled out from under a mat, they iirc were still operating on Connally.
So somehow the conspirators knew the wounds, knew a fraction of lead was left behind, knew to plant a bullet with one side flattened which is totally consistent with CE399's sideways journey through Connally's torso, knew that CE399 was slowed down as it passed through Kennedy and Connally so it only fractured Connally's wrist instead of smashing it as a full speed bullet will do and then CE399 barely had enough kinetic energy left to only partially penetrate Connally's thigh.
So either the conspirators were extremely powerful clairvoyants or CE399 was by definition the only plausible bullet that satisfied all of the requirements!"
John's hypothetical situation falls down because anyone who was aware that the bullet had smashed JBC's wrist bone would've created a "plant' that was way more deformed. The idea of a rotating bullet was something that was invented way after the day of the assassination.
If conspirators had indeed created a bullet to mimic what they thought the situation was, it would imply they thought the bullet had only hit JFK and hadn't hit JBC at all.
Maybe these conspirators were aware that Hulmes and Boswell thought a bullet had been forced out of JFK by massaging his chest during CPR or something and made the plant before it was realized there was an exit wound on the neck. Maybe they were being updated by Silbert and O' Neill.
It's possible to speculate almost any scenario.