You can not place a broken down MC rifle in the paper bag Oswald carried that morning, without disregarding the testimony of Buell Frazier and Randle, who are the only two people who actually saw the bag.
Just playing Devil's Advocate...
The assassin suddenly breaks his routine and goes to the Paine household on Thursday. He shows up at Frazier's with a suspiciously long package. It's way too long for a lunch bag. Just because Frazier is out by his estimation of its length by a few inches doesn't mean anything as he's not really paying attention to it. Frazier sees Oswald collect the long package from the vehicle and make his way toward the TSBD:
"You can not place a broken down MC rifle in the paper bag Oswald carried that morning"It's obvious the package contains the rifle and you can't prove it doesn't.
You can not tie the MC rifle to Oswald, execept for the opinion of a FBI Questioned Documents Expert, who, claimed Oswald's handwriting is on the Klein's order form, the envelope and the money order, despite the fact that all he had were easily manipulated photocopies. But even if Oswald ordered the rifle, in March, that still doesn't mean he owned it, either back then or in November 1963
'You've only got an expert from the FBI confirming the rifle is Oswald's'

This is supposed to be an argument
against Oswald owning the rifle?
You can not place Oswald on the 6th floor of the TSBD at 12:30 on 11/22/63
And you can't place him anywhere else.
If, as you say, Oswald isn't on the sixth floor taking the shot, where is he?
You can't say with any certainty.
nor can you show that Oswald came down to the second floor by the stairs after the shots were fired. Dorothy Garner, who was on the 4th floor, told the office of Barefoot Sanders that she saw Victoria Adams and Sandra Styles go downstairs and saw Truly and Baker come up. In other words, she should have seen Oswald if he had gone down the stairs, which he clearly didn't.
All of this is predicated on the second floor lunchroom encounter between Baker, Truly and Oswald.
If, as many believe, this encounter doesn't take place there's no need for Oswald to be running anywhere.
After Baker and Truly pass by on their way to the roof he can just cruise down the stairs and out the front door before the building is locked down.
So, your evidence that Oswald killed Kennedy is what exactly?
Your evidence that he didn't is what?
The point of this exercise is to demonstrate the importance of the 'narrative'.
Any detail can be taken in isolation and interpreted almost any way you please. But all the details must fit into an overall 'narrative' and the LNers have their narrative provided for them. It can't be proven what was in the bag Oswald carried to the TSBD but in the LNer narrative it's obvious.
Any 'counter-narrative' must include the same details and, in my opinion, must be very close to what actually happened that day.