Magazine follower marks, ejector marks, or extractor marks; it makes no difference. Thompson's claim that "the only mark borne by the dented case, linking it to Oswald's rifle, could not have been incurred on November 22" is false. Frazier used the marks made on CE 543 by the firing pin and bolt face of the rifle to positively match it to the rifle.
I really don't know what you are referring to. Post an image of CE-543 with an arrow pointing to the indentation that you are referring to. Thompson was referring to the dent on the mouth of the shell.
That is false.
"It is the opinion of the panel that the dent on the mouth of the CE 543 cartridge case was produced when the cartridge case was ejected from the rifle. This condition was duplicated during test-firing of the CE 139 rifle by the panel."
The CE 139 rifle is not a substitution for the CE 139 rifle. It is the rifle. Oswald's rifle.
https://www.history-matters.com/archive/jfk/hsca/reportvols/vol7/html/HSCA_Vol7_0197a.htm
As part of Josiah’s participation in the Life magazine photo shoot in 1967 Thompson was able to view the rifle and all the shell casings that were fired in or associated with LHO’s rifle during and since the assassination.
Somehow this message seems to have gotten lost here, but the whole point Josiah made was CE 543 is the only shell casing he observed out of the 30+ shells that had been fired in the rifle since the assassination including CE 544, CE545, and CE 141, the unfired cartridge, that did not have the indentation on the side of the shell that the FBI identified as a “chamber mark” and as having been produced by the chamber of the rifle. The point of his observation is without the “chamber mark” on CE 543, it is proof it was not fired in the rifle. His point is not that CE 543 was not in the chamber of the rifle.
Page 145, in Six Seconds in Dallas, has the picture of the shells and the explanation. The one without the arrow is CE 543. There is an anomaly, most likely a burr from the reamer during manufacturing, in the chamber of the rifle that impresses an indentation on the shell casing when it is fired, or the chamber expanded due to heat. CE 543 lacks that indentation in the side of the shell casing and is the only shell, out of 30+ viewed by Josiah that had been in the rifle or fired by the FBI while testing the rifle, that lacks the indentation. All the others have the indentation to a varying degree.
Additionally, CE 141, the unfired cartridge, has the indentation in the side of the shell casing, just from being introduced into an expanded chamber due to heat of the other cartridges having been fired. CE 543 by lacking the indentation or "chamber mark" indicates that it was never actually fired in the rifle.
Magazine follower marks will only be on the last shell in the clip. The last shell, in this instance is CE 141 the unfired cartridge, which was discovered still loaded in the chamber, not CE 543. CE 543 was known to be in the chamber of the rifle and dryfired but was not the last shell. on 11/22
Josiah clearly states based on his observation LHO only fired two shots not three, that is the whole point he was trying to make.