Since the MC rifle found on the 6th floor TSBD had a scope mount that needed shims to change the mount angle enough that the scope reticle could be adjusted in elevation properly, then that suggests 2 possibilities:
A. The shooter was unaware the scope was out of alignment and he fired the 1st shot using the scope only to then realize how far off it was and then he switched to using the iron sights.
B. The shooter WAS aware the scope was out of alignment before he began shooting therefore most probable he fired 1st shot using the iron sights as well as 2nd and 3rd shots.
If A. Then the idea of a Z193 shot fired thru foliage of a tree is not that implausible if the shooter was using the more restricted sight picture of the scope when he had started tracking the target a few seconds prior to firing the shot at Z193.
If B however, it’s implausible the shooter would be unaware of how the much foliage of the tree would interfere with his sight picture given the much larger area background in his LOS while he used iron sights.
If A however, Its less probable the shooter was Oswald as surely he would be aware of this misalignment problem, thus would use irons sights for shot the 1st shot, thus he would be aware of the tree foliage in relation to his iron sight picture and therefore he would have NOT likely fired a 1st shot at Z193 thru ANY % of tree foliage.