Many obvious facts refute the lone-gunman theory. Here are some of them:
-- Even the HSCA admitted that the Zapruder film shows that JFK was hit with a shot at around Z186-190. JFK's cheeks puff at Z188. At around Z200, JFK's movements suddenly freeze; his right hand abruptly stops in the middle of a waving motion; his right hand also drops to the chin or throat level in a fraction of a second and stays there until he disappears behind the freeway sign at Z207; and his head moves rapidly from the right toward his wife on his left. The HSCA's photographic experts detected a strong blur/jiggle episode from Z189-197. Here's the problem for the lone-gunman theory: The sixth-floor gunman's view of JFK was obscured by the intervening oak tree from Z166-209. Obviously, this shot did not come from the sixth-floor window.
-- At least 2 seconds after JFK visibly reacts to the Z186-190 shot, he is clearly struck again at Z226. Beginning at Z226, Kennedy's body is visibly jolted sharply forward, and the position of his hands and elbows--particularly his elbows--changes dramatically, as they are flung upward and forward. The force and speed of these movements are quite startling when one compares Z226, where they are first discernible, to Z232 just 1/3-second later.
Although the WC, and to a great extent the HSCA, ignored these movements, they are among the most dramatic and visible reactions in the entire Zapruder film. In addition, Dr. Luis Alvarez and HSCA photographic experts Hartmann and Scott noted a blur/jiggle episode at around Z225-229. This shot must have hit at right around Z224. Needless to say, this means the Zapruder film shows that JFK suffered two non-fatal shots, which means that at least five shots were fired at him (Z186-190, Z224, Z234, Z312, and the Tague curb shot).
-- There is strong evidence in the Zapruder film that a shot was fired at right around Z285:
* There is a blur/jiggle episode from Z289-295.
* Special Agent Warren Taylor said he heard a shot at the very instant his left foot touched the ground after he opened the door to exit the vehicle in which he was riding. A photo taken by newsman James Altgens at Z255, shows Taylor in the process of opening the door--1.65 seconds before Z285.
* Texas Highway Patrolman Milton Wright said he heard a shot just as his car turned onto Elm Street. The above-mentioned Altgens photo shows that Wright’s car had not made that turn by Z255 but was nearing the corner. By Z300, Wright's car was on Elm Street.
* SSA William Greer, the limousine's driver, snaps his head to the rear beginning
at Z301.
* SSA Roy Kellerman, who is sitting next to Greer, seems to duck his head beginning at Z293. His head tips noticeably forward, in an apparent ducking motion.
* Jean Hill begins to snap her head to the right at around Z295.
Government-hired experts have studiously avoided dealing with the clear photographic and jiggle-analysis evidence of a shot at around Z285, but many private researchers have discussed it. The Z285 shot refutes the lone-gunman theory because it means that at least six shots were fired (Z186-190, Z224, Z234, Z285, Z312, and the Tague curb shot).
More information on these shots can be found in this article:
Reactions to Six Shots in the Zapruder Film
https://drive.google.com/file/d/1nnp3Vch_KMOB_qufAhlQOCLTTS9jqNV0/view-- Firearms experience and extensive testing have established that CE 543, the dented shell found in the sniper's nest, could not have been used to fire a bullet during the assassination because the dent is so severe that it would have prevented the shell from discharging the missile. The fact that this shell was not fired during the assassination is also seen in the following facts:
CE 543 does not have the alleged murder weapon’s characteristic chambering mark on its side, whereas the two other shells do. CE 543 has follower marks on its bottom, but these marks do not appear on the two other shells nor on any of the shells that were ejected from the rifle in the WC’s test firings. CE 543 could not have been marked by the alleged murder weapon’s magazine follower during the assassination because it was not the last shell in the clip. No experiment, including Chad Zimmerman's, has produced a shell as dented as CE 543 (see my discussion on this point in my article cited below).
Thus, unless the police "missed/overlooked" a shell in the sixth-floor sniper's nest, the sixth-floor gunman could have only fired two shots.
For more information on the dented shell, see this article:
The Dented Bullet Shell: Hard Evidence of Conspiracy in the JFK Assassination?
https://drive.google.com/file/d/1Ihue8a0GmN_Ptl38bPjpu1F99nqU0Z6f/view