The Chances That Harry Barotti Shot Himself Twice

I don't know enough about 1920s cars to say this definitively, but I bet you anything that a backfire is multiple sounds on a 1920s car. So we're now down to could Harry Barotti physically shoot himself twice? Is that on your understanding really when it drills down to what are the chances that this man would have shot himself twice versus grace? There's some layers of complexity that if I'm assessing this case, if I were the crime scene investigator, I would be looking for all of this type of evidence at the scene.