To me, it's pretty obvious when the last two shots were taken and where they were fired from. The second shot struck both JFK and JBC around Z222 and of course the headshot which struck at Z313. That latter seems to be the on indisputable fact that everyone is willing to agree on. How could they not? I have no doubts about the second shot but it's a little hard to pinpoint since JFK was hidden when it struck and we are forced to rely on the reaction time of the victims as well as that of Zapruder himself. To me, Z222 is the best fit if all the clues are taken into account. The only one for which is much debate is the first shot. There is no definitive event that tells us exactly when that shot was taken but to me, Z147 seems to hit the sweet spot when all clues are factored in. I am a little less convinced about that one than the subsequent shots, but I think the preponderance of evidence points to a shot in the Z147-148 window, with the bullet striking outside the limo, probably to the right althought he possibility exists it hit an intervening object before reaching the limo. That one will likely remain a mystery.