I am not an expert on firearms, but how do you differentiate the bullets by brand? Casings, for sure, but I am not sure of the bullets. Did they do a lead composition test on the bullets as they did for Oswald’s bullets found in the sniper’s perch, in order to compare them to the bullets and fragments of bullets found in the assassination of Kennedy?
From the horses orifice:
https://www.ojp.gov/ncjrs/virtual-library/abstracts/jfk-john-f-kennedy-assassination-bullet-analyses
Read some books on it. I listed 3 to start with but there are others.
Just a segment of the 1979 House Subcommittee on Assassinations:
(68) -Of the four expended cartridge cases found at the scene of the Tippit murder, two were of Western Cartridge Co. manufacture, two of Remington-Peters. The autopsy of Tippit, however, revealed three bullets of Western Cartridge Co. manufacture and one of Remington-Peters.
https://history-matters.com/archive/jfk/hsca/reportvols/vol7/pdf/HSCA_Vol7_F1_Introduction.pdf