There is one other problem I have with LHO's marksmanship- shooting from the 6th floor he would also have to compensate for the lack of bullet drop due to gravity- any experienced hunter can tell you that with a downhill shot you would have to shoot low. Bullets follow an arc and their speed determines how flat it is. I don't know the data for the particular round he supposedly used, but even with a very fast round you would still have to compensate for drop. I just don't buy that he could fire off three rounds that fast with that gun and hit a target at that angle-unless it was the (un)luckiest shot in history. As someone else mentioned, we will never really know the truth.
Does anyone know if Oswald had a chance to practice with that rifle?