To address the "lack of damage" to CE-399...
The bullet (CE-399) leaves the muzzle of the Carcano traveling around 2100 feet per second.
The bullet, traveling roughly 1700 feet per second, strikes Kennedy in the upper back and exits the neck.
The bullet, now slowed having passed through Kennedy's neck, hits Connally in the back, causing an 8mm x 15mm elliptical wound. This wound measurement proves that the bullet was tumbling when it hit Connally's back, proof that the bullet had passed through something else BEFORE hitting Connally in the back.
The bullet, now traveling at around half of it's original speed, strikes Connally's fifth rib, completely shattering it. Damage to the bullet was minimal due to the fact that it was not traveling anywhere near full speed when it struck the rib.
The bullet exits Connally's chest and while traveling less than half of it's original rate of speed, enters the right wrist, striking the radius bone. Again, damage to the bullet is minimal because of it's slow rate of speed when it struck the radius.
The bullet exits the palm side of the wrist and while traveling at less than one-fifth of it's original speed, enters the left thigh and embedding itself in the thigh muscles. The bullet didn't go any further because it was not traveling fast enough upon striking the thigh.
The bottom line is that damage to the bullet was minimal because, when it struck rib bone and radius bone, it simply had been slowed considerably, moving too slowly to be damaged. The bullet would have been greatly fragmented (basically destroyed), if when it struck the radius bone in Connally's right wrist, it was traveling at the same rate of speed as it was when it struck Kennedy in the upper back.