With regard to the poll question, The Warren Commission had several US military sharpshooters attempt to repeat LHO's alleged shooting time with the same weapon and they could not do so. Forensically, this would constitute evidence that it was not reasonable to conclude that Oswald (whose former Marine colleagues told the Warren Commission he was a poor shot) fired all three rounds in the time stated.
In answer to Twilite's question above, the time of the (alleged) three rounds being fired is established by the cine film recorded by Abraham Zapruder. His movie evidence is not challenged.
It has been established that, from where LHO was sited in the book depository, the angle and trajectory of the fatal third round (if fired by him) would have had to have been through the thick foliage of a Texas Live Oak tree which was in the line of fire. The Texas Live Oak sheds its foliage in the Spring so it was in full bloom in November. LHO would not have been able to see the President when the motorcade was in the position it was when the 'kill shot' was fired. If he fired that round (which I do not believe he did), then he sure got lucky..!!
If LHO was the only shooter, it would have been more logical for him to fire when the motorcade took that tight turn at Nine and Elm. At that point the Presidents' full body was in view at close range, the car had slowed down to a slow crawl in order to take the bend and the shot would have been a very simple one. Why wait until the car was moving away from him and gathering speed? LHO would have had only the President's shoulders and head to aim at and the tree would have been obscuring his aim. It doesn't make sense.
Back, and to the left......... back, and to the left...... back, and to the left.....
The image of the President's head being blown open and thrown backwards to the left is, for me, the single most damning piece of evidence.
The Zapruder film clearly shows the President being struck by a shot fired from in front on a ground level trajectory. Ballistically it is not feasible for the fatal third shot to have been fired by LHO. The evidence of the Zapruder film is quite conclusive in my opinion and clearly indicates a shot fired from the area of the picket fence on the grassy knoll.
For me, these factors make it, not only impossible for a single shooter sited where LHO is alleged to have fired from, but also they make the official version of events simply not feasible. I doubt very much that any official enquiry into such an event today could possibly come to the same conclusion.
Other questions also arise, such as how many rounds were really fired. One witness standing by an underpass was hit by fragments when a round hit the concrete wall he was standing next to. Eye witnesses said they heard more than three shots.... and later told reporters that their evidence was falsified and tampered with in the final version of the Warren Commission's report, to say they only heard three.
The evidence of wounds to Governor Connolly give rise to the ludicrous "Magic Bullet" scenario. Again, the Zapruder film squelches the official version of events. Even a bullet zig-zagging crazily around by pinging off hard surfaces inside the car can't hang motionless in the air for nearly two seconds before resuming movement and causing more wounds to passengers in the vehicle. Again, it is simply not feasible.
That few seconds of cine film is the most damning indictment of the Warren Commission's conclusions. For me, the most overwhelming evidence of a conspiracy involving more than one shooter is the view of the fatal third round. Whenever anybody ever says that Oswald acted alone, five words are all it takes to quash that statement....
Back, and to the left..... back, and to the left......