The 3 stacked boxes suggest the shooter was going to shoot with rifle sticking partly out the window. Unless Malcolm Couch , Bob Jackson and Amos Euins were encouraged to fabricate a story, their WC testimony confirms this was the plan, since they all saw a rifle stuck OUT the window.
There is no logical reason why Oswald or some other TSBD shooter would try a pot shot while standing at Z124.
The rifle was found with the scope so out of alignment that a shim had to be inserted under the mount itself to change the mount angle. The metal bracket that held the scope was not bent, so it appears that the rifle was assembled without the shim on purpose.
It could be Oswald never had intended to use the scope , and assembled the rifle without the requisite shim to introduce speculation about the rifle being planted after the fact.
This might have been a fantasy in Oswald’s OCD mind of acquiring infamy after a trial jury would be convinced he was in fact a patsy.
As to Why Clint Hill did not hear a shot before Z224, there’s the volume of crowd noise to consider besides just some motorcycle noise and some possible desensitization of the SS to sudden 100 db level motorcycle backfires they had probably already experienced multiple times during the whole motorcade trip.
Ok that is about as far to the LN side that I dare venture otherwise my credibility as a CT Skeptic would in jeopardy 
One thing we will never know is what Oswald was thinking because he never told us. Unless you want to conduct a seance, I doubt he ever will.
We don't know whether Oswald used the scope or the fixed sights although I lean toward him using the scope. From my own limited experience, I know the scope is a great aid in quickly reacquiring the target. It is much easier to put the cross hairs on the target the target then getting the front and rear sights properly aligned on the target. Both the scope and the fixed sights would aim high at the range Oswald fired at. As the WCR pointed out, this would actually aid a shooter firing at a moving target since he would need to lead the target with his aim. Oswald might have known this and taken it into account, or it could have been just blind dumb luck. What we do know is the Carcano was the murder weapon because the ballistics matching clearly establishes that. Not only was Oswald's Carcano positively matched to the recovered bullets, but no other bullets from any other rifle were ever recovered. Why do you suppose that is?
