Someone let lil' Tommy out of his pen.
In your tiny mind CE399 somehow represents a bullet that smashed one of the most dense, hardest bones in the body.
EVERY SINGLE TEST done with a bullet fired into this bone deformed the bullet to a massive extent, barely recognisable from its original shape.
But your tiny, tiny brain believes uttering the chant "tumbling" somehow, in some insane version of reality, makes things alright.
Dear danny BOY o'meara,
In "Cold Case: JFK," the Haags showed that that kind of bullet fired from that kind of rifle has a tendency to start yawing/tumbling when it exits something soft, like a block of ballistics gel or a human neck.
Which would probably explain why the entrance wound in JBC's back was oblong in shape, why his fifth rib was smashed the way it was, why the exit wound in his chest was so large, why JBC's lapel and tie flapped, how fibers from his jacket were carried by the rear end of CE-399 into his wrist wound, and how his radial bone was smashed the way it was.
In short, CE-399 was deformed so strangely because it hit JBC's rib sideways and was tumbling/twirling when it smashed his radial bone.
If the guys at the arsenal had fired their test bullets so that they passed through a block of ballistics gel or a person's neck before hitting a cadaver's wrist, they might have ended up with the same result -- a bullet whose nose was pristine, but whose rear 1/3 was flattened on one side and which had lost some of its lead core out of its rear-end.
But even if they fire a thousand bullets like that, ending up with a bullet that looks like CE-399 isn't guaranteed, because it's impossible to replicate the exact deformation experienced by a bullet when it passes through something soft (e.g., JFK's neck) and then starts yawing and penetrates something else (e.g., JBC's upper torso) and smashes something sideways (e.g., JBC's 5th rib) and exits that something else (JBC's torso) and then penetrates something else (e.g., JBC's wrist) and smashes something hard (e.g., JBC's radial bone) while travelling initially about 2100 feet-per-second.
D'oh
-- Tom