SA Hickey had the AR-15 raised UP in the back seat while the car was in Motion.
Yes, you're right, Hickey pulled out the AR AFTER the shooting.... There isn't a photo that shows Hickey with a weapon prior to, or during the shooting....And no witness reported seeing Hickey with a weapon during the shooting... The muzzle blast from an AR-15 would definitely have drew some attention....
With regard to the AR-15 muzzle blast Not drawing attention, there are many things that also were allegedly in motion that also failed to draw anyone's attention and were Not captured on Any of the Images taken before, during, or immediately following the Kill Shot. #1 would be SA Lem Johns jumping out of the LBJ SS Follow-Up Car and running down Elm St toward the LBJ Convertible. Not a single eyewitness on Elm St saw the alleged action of Lem Johns jumping out of a car in the JFK Motorcade and then running down the middle of Elm St. This extended action also is Not on 1 single assassination Image taken that day. There was only 1 car separating/between The Queen Mary which carried the AR-15 and the LBJ SS Follow-Up Car carrying SA Lem Johns. If eyewitnesses could miss seeing Lem Johns doing his thing in the middle of Elm St, they could also easily miss an AR-15 muzzle blast INSIDE the confines of the Queen Mary.