[Lx]

Maybe instead of everyone saying, 3 shots, first cartridge is loaded; the presumption is 3 shots after the initial one if there were possibly four shots.

That makes good sense, why eject the last round? Does anyone know if there was one left in the chamber?

[Shooter 2.5]

Oswald chambered a fourth unfired round. There were three empty cartidges found on the floor of the “sniper’s nest”. The two guys eating lunch on the fifth floor not only heard the three shots but they also heard the three empties hitting the floor through the open windows. Dust and debris fell down on them from the fifth floor ceiling with each shot.