Donohue was probably correct that the fatal head shot couldn?t have come from the Manilcher Carcano.
Donahue describes in his book and displays in the photo-section an HSCA ballistic gelatin test showing an AR-15 bullet disintegrating which he liken to the metal fragmentation seen in the Kennedy skull X-rays. By contrast, Donahue showed the photo from a similar test for a 6.5mm Carcano bullet; it remained intact.
The primary problem with all that (which eluded Donahue (a gunsmith expert) and McLaren (a crime and weapon expert) is that there was no simulant for hard tissue (ie: skull bone). The gelatin tests in Donahue's book simulated soft tissue only. McLaren's own test was to fire a 6.5mm bullet through a melon; again, no hard tissue simulant (the melon rind is not equal to skull bone tissue). Donahue and McLaren were certainly respected experts in their fields, just that one of their fields didn't include terminal ballistics.
This happens when people become wedded to a pet theory. Their judgment is clouded (see Mason Theory). Donahue was shown the Bronson film, disbelieved what they trying to explain to him, and still his publisher issued the paperback version. McLaren may even be worst; he must have seen the Bronson film more times than Donahue and had a few decades of having problems with the theory pointed out.
We?ll never know because Kennedy didn?t get a proper autopsy...
Yeah, sure.