What evidence do you believe we should have that we do not under that circumstances that would satisfy you of Oswald's ownership of the MC rifle?
I don't know if there is any evidence that could prove beyond a reasonable doubt that Oswald owned the rifle allegedly found on the 6th floor, but that doesn't entitle you to lie about the evidence that does exist.
I can think of a few things that would make your case stronger though:
- any USPS documentation of the alleged shipment from Klein's to PO box 2915
- original documents
- a signed and dated signature form from whoever picked up such a package
- an eyewitness description of the person who picked up such a package
- any evidence, eyewitness or otherwise, placing that specific rifle (not just one that resembled it) in Oswald's possession at any time
But this is all a red herring, because proving that he owned C2766 doesn't actually tell you anything about who killed the president.