Common sense tells me it was imperative to use multiple shooters to make sure the CIA target would not survive. Kennedy was going to break up the CIA and they knew it.
All bullets at the sniper’s nest on the 6th floor, all bullets fragments found and the “Pristine “ bullet were all tested. They cam from the same production lot. They all had the same lead content, and well as all the other impurities were at the same percentages.