IMO, the missed shot was the 3rd shot fired about 0.5 sec after 2nd shot at Z313 and 5 sec after 1st shot that hit both JFK and JC at Z224
This is the theoretical result of a semi auto rifle having been the weapon used by the TSBD shooter.
The shooter saw he did not score head shot at Z224 so took another 4.8 secs to carefully aim
and squeezed off 2 more rounds rapidly of which the 2nd hit JFK high on the right rear side of the head while the 3rd round flew high due to the effect of muzzle rise when firing a semi auto rifle rapidly. That 3rd round was the one that hit the curb near James Tague and because that bullet had a different metal composition than an MC bullet may explain the anomaly of the curb analysis that seems to rule out an MC bullet having struck the curb.
Your Theory kinda sounds like the HSCA 4 Shot scenario. For whatever reason though, you want to keep the shots being fired coming from the rear of the JFK Limo. The Tague/Curb episode does Not have to begin with a shot being fired from behind the JFK Limo.
