Exhibit 564 is again, a portion of the primer of the cartridge case fired by me in the rifle number 139 appearing on the left side of the vertical dividing line through the center of the photograph, and on the right side a portion of the surface of the cartridge case, Exhibit 545, showing its primer and the marks on it.
In the photograph four circles, or portions of circles, have been drawn, circling some of the areas where individual microscopic characteristics are found which permitted identifying the two cartridge cases as having been fired in the same weapon.
In the upper circle are again two ridges separated by a groove, the lower right-hand end of which is blocked by a raised portion in the metal of the primer.
Circle number 2 is again a depression bounded on the top by a long sloping groove, sloping from the upper left subsequently to the lower right.
In circle number 3 there is a series of ridges running horizontally across the photograph. The lowest of these three ridges is a rather wide round-topped ridge.
Circle number 4 shows the left-hand side of a figure which you could roughly call a Z in the primer, which consists of a horizontal or nearly horizontal line running from left to right which meets a second line running from right down to the left, which again meets a third line which runs from the left to the right. This is shown in both photographs as the three lines which form the shape of a Z on the primer.

Mr. Eisenberg.

Mr. Frazier, on this photograph there is shown a mark at approximately 3 o'clock on the left-hand side of the picture, and 9 o'clock on the right-hand side, and the marks seem to be different in the two pictures, being broader on the left-hand, C-14, than on the right, C-38. Could you explain the genesis of the difference? It seems to extend further down.

Mr. Frazier.

Approximately in the center of the photograph where the two images meet, there is a scraped area which is the result of the surface of the metal of the bolt scraping the surface of the primer as the bolt was turned in opening the bolt to extract the cartridge.
On the test cartridge case, this area is much broader and coarser because the bolt was pressing more tightly against the primer when it was turned. On the evidence cartridge case, the marks are relatively fine, separated, and even show portions of the surface of the primer in between the circular marks left by the rotating bolt. The reason is that this primer was not being pressed as tightly against the bolt at the time it was turned.

Mr. Eisenberg.

Would that be due to differences in the construction of the cartridge the two cartridges?

Mr. Frazier.

It could be differences in the cartridge, but primarily it would be a difference in the amount of setback of the cartridge against the bolt at the time it was fired.
If a cartridge is slightly away from the bolt when it is fired, the primer is blown back out of the cartridge. As the pressure builds up, the cartridge then moves back and reseats the primer in the primer pocket. The manner in which that movement of the primer out and back in is accomplished determines how tightly the primer will bear against the face of the breach after the cartridge has been fired.

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