I distinctly remember watching a TV Special ( CBS w/ Walter Cronkite, IIRC) where they duplicated the shots.
They had a similar rifle, elevated to the same height, moving target, the whole enchilada.
It could and was done.
And seeing the 'missing' frames of the Zapruder film, there is absolutely no question that the wound on Kennedy's right front head was an exit wound.
That shot didn't come from the side or front. It came from the rear.
Many want desperately to put exactitude on an event that will never have it. You are right about that shot coming from the rear. But we cannot say that Oswald pulled the trigger, because others were involved. At best, we will never know. I happen to believe Oswald was a carefully set screen, given all of the facts as well as the shooting forensics.