Mr. Frazier. Yes, sir.
Mr. Eisenberg. May I have this introduced as 558?
Representative Boggs. It may be admitted.
(The photograph referred to was marked Commission Exhibit No. 558, and received in evidence.)
Mr. Eisenberg. What is the magnification of this bolt-face photograph?
Mr. Frazier. Approximately 11 diameters.
Mr. Eisenberg. Could you slip out the bolt of the rifle so we could see how it compares, and show us the part of the bolt which is photographed?
Mr. Frazier. Orienting the photograph with the writing at the bottom, orients the bolt also, as it comes out of the rifle—with the slot shown as a groove on the bottom of the bolt. Then the extractor on the bolt, is the area shown at the left side of the photograph, as you view it—the actual bolt face itself is inset into the bolt below the surface of the extractor, and a supporting shoulder around it, and in the center, of course, is the firing-pin hole and the firing pin.
The marks produced during manufacture are the marks seen on the bolt face; filing marks, machining marks of the various types, even forging marks or casting marks if the bolt happens to be forged or cast. And then variations which occur in these marks during the life of the weapon are very important in identification, because many of the machining marks can be flattened out, can be changed, by merely a grain of sand between the face of the cartridge case and the bolt at the time a shot is fired, which will itself scratch and dent the bolt face. So the bolt face will pick up a characteristic pattern of marks which are peculiar to it.
The same is true of extractors and ejectors. They are in turn machined and will have a pattern of marks or scratches on their surfaces which will mark cartridge cases in the same manner each time.