Mr. Belin. What difference does that make?
Mr. Barnes. The powder couldn't get out like a pistol where the cylinder is open, and there is no casing around the cylinder of a revolver, and the chamber of a rifle, it is enclosed with the metal all the way around.
Mr. Belin. Well, I operate the bolt on the rifle, does that make a difference about letting the gas or residue escape?
Mr. Barnes. No; all your explosives have already gone down the barrel. It is not coming down the side when you operate the chamber. There is no pressure there.
Mr. Belin. What you are saying then is, that it is the pressure at the time of firing in an open chamber that creates the major portion of this residue?
Mr. Barnes. That's right.
Mr. Belin. If you were to have a positive nitrate test on a person's hands, and by positive, I mean it would show the presence of nitrate, would you say, without knowing anything about the firearm that the person fired, that it was more likely that he had fired a .38 caliber revolver, or a bolt-action rifle?
I mean a nonautomatic revolver?
Mr. Barnes. Let me get your question to see if I am correct. If there were nitrates present?
Mr. Belin. Yes.