I lent out my copy of “Case Closed” some years ago (which never came back) and I think this was documented in it.
I seem to recall a diagram that showed various velocities of the ‘magic bullet’ before entry and after entry into JFK’s neck. I’ve been able to find how fast the bullet was probably traveling before it made contact, but less able to find how much it had slown down after it exited his neck.
Anyone???
Wiki is neither the be all nor end all, but they say the bullet exited JFK’s neck at 1500 fps, beginning to tumble. It exited Connally (the first time) at about 900 fps and went into his arm/hand, exiting his body the second time at 400 fps when it entered his thigh, staying there until it fell out at Parkland, landing on the next stretcher over. The Wiki article seems to lean toward conspiracy soon after that.