TG-
This is a photo of the small round hole in the rear of Gov. JBC's assassination-day shirt.

This small round shirt-hole was actually enlarged twice, legitimately, once by the FBI and once by the HSCA, to test cloth for metallic residue. The initial hole was even smaller, but unfortunately it appears there are no photos of the original, even smaller hole.
JBC's surgeon, Dr. Robert Shaw, who worked on 700-odd wartime bullet wounds while serving in the WWII Army, was of the opinion that JBC received a direct shot from above and behind, which left an ovoid wound, north-south on JBC's back, per his drawing of the wound.
Shaw described the wound as “elliptical” which is a symmetrical shape, not “ovoid” or egg-shaped, which is not symmetrical. SBT proponents suggest the two terms are interchangeable. They are not.
An elliptical shaped entry wound is made by a pristine bullet striking the skin surface at an angle other than 90 degrees. An ovoid shape can be made by a yawing bullet. A yawing or tumbling bullet cannot make a symmetrical elliptical entry wound.
Shaw expanded or debrided JBC's back wound to remove dead flesh and any foreign material, leading to confusion about the actual size of initial wound later.
In addition, the exit hole in JBC's assassination-day suit is also small and round, indicating the slug was not tumbling as it exited JBC.

I conclude the slug that struck Gov. JBC's back was not tumbling, in concordance with the sentiments of Dr. Shaw, a very experienced surgeon, with no evident axes to grind.
Shaw also described the missile having made a “small tunnelling wound” (7 HSCA 149).
The "tumbling bullet" appears to be among the many myths subscribed to by LNT'ers, or CT'ers, regarding the JFKA, in order to buttress their narratives.
https://www.tsl.texas.gov/lobbyexhibits/jfk-suit
Although I am not a CT by any means, I agree that the evidence against the SBT is substantial.