We don’t know exactly where Queen Mary was at the time of Hickey's headshot at Z312 (the hollowpoint slug hits JFK at Z313). Queen Mary might have been directly behind the JFK limo or a bit to one side -- & Queen Mary might have been on an angle.
We don’t know exactly where SSA Hickey was sitting/standing in Queen Mary at Z312 (he was or had been sitting hi up in the left rear seat sitting on 2 leather cases)(he was holding the AR15).
But we do know where the AR15 was at Z310, ie the time of the 2nd last shot of Hickey's auto burst of at least 4 shots…..
…… The slug had to get over the windshield of Queen Mary...
…… & the slug had to get under the divider/rollbar of the JFK limo…
…… & the slug had to go clear through between the upturned vizors on Queen Mary.
The drawing below shows the available window for the pozzy of the AR15 at Z310 – relative to Queen Mary.
Where exactly Hickey had to be in Queen Mary depends on exactly where Queen Mary was at Z310 – as i sayd, Queen Mary might have been left or right of the JFK limo, & it might have been on an angle relative to the JFK limo -- & we don’t know whether Queen Mary was 5' or 6' or 7' from the JFK limo.
I reckon that Hickey had moved over to his right & that the AR15 was near the centerline of Queen Mary for the whole of the auto burst.
I reckon that Hickey had the AR15 in both hands for the whole of the auto burst.
And i reckon that Hickey was holding the AR15 up high, & out in front of him (he had to lift & swing the AR15 over O'Donnell's head)(sitting in the jumpseat).
We don’t know whether Hickey was intending to shimmy over to the centerline of Queen Mary so that Hickey could stand & turn around to target the TSBD – or, he might have been planning on kneeling on the rear seat with his right knee – or standing on the rear seat with his right foot.
Anyhow, the problem with Hickey killing JFK was never how he managed to have the AR15 hi enuff to clear the Queen Mary windshield – it turns out that the problem was how he managed to have the AR15 in that there small window to make the dent.
While i am hot – there are at least 2 problems with the pix.
Firstly SSA Hill was not in front of Queen Mary at Z313 – he was back a ways, not yet level with the front wheel.
Secondly SSA McIntyre on the left running board was not looking at Hill – the Bronson footage shows us that McIntyre was looking at Hickey (koz he had seen Hickey pick up the AR15).
McIntyre snaps his head forward & looks at JFK after Z313 (seen in Bronson footage), ie after Hickey's auto burst (to see whether any damage has been dunn).
Another problem. The red lines pass over Jackie -- they should pass directly over JFK or nearly. I think that JFK might have been a little closer to the centerline of the JFK limo. And i think that Queen Mary might have been over to our left a bit. Anyhow, the red lines should be over the top of JFK's head, or nearly. One solution to this problem is that during the auto burst the AR15 might have been swinging left to right (from Hickey's point of view), while swinging downwards – if so then the red lines (for the shot at Z310) can indeed be somewhere between JFK & Jackie.