With regard to what you are saying above, what Authority did the SS have to demand/take possession of JFK's body? And, there is nothing "silly" about having a SS Agent or 2 leave the Queen Mary in order to have the "6" of the POTUS. Not sure what the value of that AR-15 is when confined to the back seat of the Queen Mary. The possibility of "friendly fire" also rules out firing it at anything in the 10-2 O'Clock line of fire.
Hickey had the AR15 inside the hozzie. And it stank, as did the 4 or 5 stinking casings in his pocket.
Later the poor lil ÄR15 was confined to nowhere --- in service for a mere 4 hrs --- then out of service for ever.
Not even toy AR15s for the kids at Xmas 1963 --- bang bang bang bang your dead ha ha ha ha --- no i'm not, i'm not the president, i'm an itchybum.