I've gave hundreds of lifts to workmates down the years, would I take note of the package they were carrying and shape etc, very likely not, however if he carried it cupped under his armpit as BWF stated he did then that's a pretty good observation that he's never waivered on, if so and as we know the rifle couldn't be disassembled to fit then you have an issue no ?
Perhaps you missed this part of post #35 by DVP in this thread:
Mr. Frazier is also on record as having said the following at the 1986 Oswald Mock Trial in London, England:
VINCENT T. BUGLIOSI -- "Mr. Frazier, is it true that you paid hardly any attention to this bag?"
BUELL WESLEY FRAZIER -- "That is true."
BUGLIOSI -- "So the bag could have been protruding out in front of his body, and you wouldn't have been able to see it, is that correct?"
FRAZIER -- "That is true."