I once herad a very simple point made by an expert military-trained sniper, and which is largely overlooked by most analysts of the Kennedy murder.
It is actually very difficult, verging on impossible, to track a moving target with a telecopic gun-sight - anyone who owns even an air-rilfe with such a sight can confirm it. It has the effect of not only magnifying the target, but also any movement of the target, and of movement of the gun itself.
It's a *fact* that at the range Oswald supposedly scored 2 virtual bullseyes in 3 shots, using a a cheap hunting rifle with *telescopic* sight, he would have to had to 'lead' Kennedy's head by nearly 2 feet. Impossible, or a miracle.
In fact 'Saul', the alleged trigger-man who got the final 'head-shot', confirmed to Hugh McDonald, writer of a definitve, now unobtainable (surprise!), book called "Appointment In Dallas", confirmed that the killers used open sights, as any competetent marksman would under the conditions they knew they would be operating.