Oswald didn't have the option of working the bolt repeatedly just before shooting, because he is in the sniper nest by 12:24 (to have placed box on window ledge just before Bronson film starts) and during this 6 minutes of time Harold Norman was RIGHT under him, and SURELY Norman would have heard the "clak clak" of the bolt operating if Oswald working it.
And Oswald had not worked the bolt therefore until he had last had the rifle in hand, IF he was the shooter seen by Arnold Rowland at 12:15 at the SW window of TSBD 6th floor.
so 15 minutes of not having worked the bolt beforehand, plus having to use iron sights fixed for a zero of 200 meters, plus having to have remained out of sight, thus NOT IN position premptively, makes this NOT a simple exercise. The top military snipers , Carlos Hathcock, and Craig Roberts were high skeptical:
?The reason I knew that Oswald could not have done it, was because I could not have done it,? said former US Marine sniper, Craig Roberts. Credited with numerous kills while serving in Vietnam , Roberts turned an objective eye on the shot heard ?round the world. After he visited Dealey Plaza, after viewing the so-called ?sniper?s lair,? on the sixth floor of the book depository, and after staring at the large oak tree overspreading much of Elm Street, Roberts said, ?I walked away from the window in disgust. I had seen all I needed to know that Oswald could not have been the lone shooter.?
Not content with his own critical appraisal, Roberts turned to another, equally knowledgeable shooter. ?According to my friend, Gunnery Sergeant Carlos Hathcock, the former senior instructor for the US Marine Corps Sniper Instructor School at Quantico, Virginia, it could not be done as described by the FBI investigators.?
?Let me tell you what we did at Quantico,? Hathcock recalls. ?We reconstructed the whole thing: the angle, the range, the moving target, the time limit, the obstacles, everything. I don?t know how many times we tried it, but we couldn?t duplicate what the Warren Commission said Oswald did. Now if I can?t do it, how in the world could a guy who was a non-qual on the rifle range and later only qualified 'marksman' do it??
https://www.liberalforum.org/topic/233951-oswald-couldnt-have-done-itshot-impossible-says-2-famed-snipers/