General Discussion

While he wasn't a top Marine on the range, he still achieved the middle range certification. He did that from a greater distance than the final shot. I personally believe he was using the iron sight on his rifle like he did on the Marine Corps range.

He had the first shot already in the chamber. There were 8.3 seconds to exercise the bolt action twice and take the three shots. There is some speculation that the first shot was deflected either by a branch or a traffic poll. Kennedy was receding slowly directly away from him so the moving target wasn't that great a consideration.

The acoustics argument of a fourth shot is bogus. The film that is out there is deceptive because they have overlayed actual gun shots. Later analysis showed the mic wasn't even in Dailey Plaza but on a different type of motorcycle probably near the Trademark (where you can hear the bell).

He was using an inexpensive but military issue Carcano rifle, a type that had been used in Europe since World War I.