Argue with the Warren Commission whose expert marksmen attempted the shots. None could do it with that rifle at a STATIONARY target.
One would have found throwing a rock more effective than the PoS rifle. It is possible to duplicate the shooting with an decent gun, decent scope, ability (none of which Oswald had) but virtually impossible with the MC even after it had been repaired. A BB gun was probably more accurate than that garbage.
Oswald had to go from the first floor to the sixth floor, assemble the gun, build the snipers nest, shoot accurately, hide the rifle and get back down in SEVENTEEN minutes without being winded. Oswald would have had to be able to fly and become invisible for that to have happened. But believing that is not too unbelievable for one who believes the WCR.
If Oswald had smuggled the rifle in in a long package and said it was curtain rods, could the rifle have already been assembled?