Hi Andrew. I agree with you, there were dozens of witnesses who referred to the final two shots being closer than the first two. There is an important issue about whether the head shot was the last shot, and what exactly the gap was between the final two shots. For example, some witnesses you mentioned in your analysis referred to a ratio of 2 to 1 between the gap lengths, so this could be 3 seconds and 1.5 seconds, or 6 seconds and 3 seconds (as suggested by Ralph Yarborough and Arnold Rowland respectively). In the Zapruder film we see the gap between JFK being hit by the two shots is about 5-7 seconds depending on exactly when he was hit during Z190-Z220, which suggests that if Arnold Rowland was close to the truth then the final shot was fired around Z360-Z400 which went wild as the Presidential limo was accelerating out of danger at that point (maybe this was the bullet which hit Tague via the kerb on Main Street?).
By contrast we have other witnesses who say that the two shots fired were both fired so rapidly they were almost simultaneously fired at the time of the head shot (as suggested by George Hickey and Sam Holland). It's hard to know the exact time frame, but it seems too rapid for a single bolt action gun to have been used (a pair of shots fired in less than 2-3 seconds probably means a second gunman was involved).
Clearly dozens of witnesses did not hear a shot after the head shot, but by contrast many definitely did hear a shot after the head shot (such as Charles Brehm and Emmett Hudson who were very close to the limo and saw the explosion we see at Z313). In addition, some witnesses like Mary Moorman and Jean Hill heard two shots after the head shot, so I am fairly certain there was at least one shot well after what we see at Z313 in the Zapruder film. I think many witnesses failed to register this final shot (or two) because they were running away in terror and were simply unaware of events due to the unfolding chaos (including a very loud siren being emitted from the Secret Service follow up car).
In summary, I find it hard to be 100% certain about whether there were 3 or more shots fired in total due to the very split witnesses. However, I am 100% certain that there were only 3 bursts of gunfire as nobody reported a fourth burst. Even AJ Millican who reported 8 shots grouped them into a pattern of 3-2-3. Naturally lone nut believers say he was confused by echoes, and conspiracy believers say each burst had a pair of shots in it. Without concrete physical evidence either way it feels rather moot, so I find it difficult to commit either way on the total number of shots fired.
Here are the timings for Oswald's shot-1 & shot-2 & for a faux shot-3.87 ft is the horizontal dist scaled by me, 106 ft is the hypotenuse dist allowing for vertical dist estimated by me.
Oswald Shot ----------- hit at ------ fired at ------ sound hit JFK at – Carcano = 2170 ft per sec.
1 --- 87 ft = 106 ft ----- Z113 ------ Z112.1 ---------- Z113.9 ----- camera runs at 18.3 frames per sec.
2 --- 184 ft = 197 ft---- Z218 ------- Z216.3 --------- Z219.6
3 --- 255 ft = 266 ft ---- Z313 -------- Z310.8 --------- Z315.2 -------- Oswald did not have a shot-3.
The time tween shot-1 & shot-2 is 104.2 frames, which is 5.7 sec. Holland reckoned that shot-1 was at Z106, which is an extra 7 frames, or 0.4 sec, which makes it 6.1 sec.
The time tween shot-2 & faux shot-3 is 94.5 frames, which is 5.2 sec.
Adding to 10.9 sec.
Here are the timings for Hickey's auto burst, based on there being 6 shots.Hickey Shot ------------- hit at ------ fired at ------ sound hit JFK at -------
6 ---- 26 ft---------------- Z313 -------- Z312.8 ---------- Z313.2 --- hit JFK in head & cracked windshield.
5 ---- AR15 = 3250 ft per sec------------ Z310.0 ---------- hit chrome trim on windshield.
4 ---- sound = 1100 ft per sec ----------- Z307.25 -------- went over the windshield, hit Elm St.
3 ---- probly 400 rpm= 6.67 rps --------- Z304.5 ---------- went over the windshield, hit Elm St.
2 ------------------------------------------- Z301.8 ----------- went over the windshield, hit Elm St.
1 ------------------------------------------- Z299.0 ---- probly hit Main St pavement & then kerb near Tague.