Mr. Eisenberg.

And what were your conclusions, Mr. Frazier?

Mr. Frazier.

I found all three of the cartridge cases had been fired in this particular weapon.

Mr. Eisenberg.

Can you describe the examination which you conducted to reach these conclusions?

Mr. Frazier.

The first step was to fire test cartridge cases in this rifle to pick up the microscopic marks which are left on all cartridge cases fired in this weapon by the face of the bolt. Then those, test cartridge cases were mounted on a comparison microscope, on the right-hand side, and on the left-hand side of the comparison microscope was mounted one of the three submitted cartridge cases, so that you could magnify the surfaces of the test and the evidence and compare the marks left on the cartridge cases by the belt face and the firing pin of the rifle.
(At this point, Mr. McCloy left the hearing room.)

Mr. Eisenberg.

I now hand you two cartridge cases, and ask you whether you can identify these cartridge cases?

Mr. Frazier.

Yes, sir; these are the two cartridge cases we fired for test purposes in Exhibit 139.

Mr. Eisenberg.

Do they have your mark on them?

Mr. Frazier.

Yes, they do.

Mr. Eisenberg.

Commissioner Boggs, may I introduce these as 557?

Representative Boggs.

They may be admitted.
(The items referred to were marked Commission Exhibit No. 557 for identification and received in evidence.)

Mr. Eisenberg.

These were the only two cartridge cases fired as tests in Exhibit 139--as tests for the purpose of identification of the cartridge cases which you examined before, 543, 544, and 545?

Mr. Frazier.

Yes, sir; these two were used in those tests. There were many other cartridge cases fired, but not for that purpose.

Mr. Eisenberg.

Can you explain how you are able to come to a conclusion that a cartridge case was fired in a particular weapon to the exclusion of all other weapons?

Mr. Frazier.

Yes, sir; during the manufacture of a weapon, there are certain things done to the mechanism of it, which are by machine or by filing, by grinding, which form the parts of the weapon into their final shape. These machining and grinding and filing operations will mark the metal with very fine scratches or turning marks and grinding marks in such a way that there will be developed on the surface of the metal a characteristic pattern. This pattern, because it is made by these accidental machine-type-operations, will be characteristic of that particular weapon, and will not be, reproduced on separate weapons. It may be a combination of marks that--the face of the bolt may be milled, then it may be in part filed to smooth off the comers, and then, as a final operation, it may be polished, or otherwise adjusted during the hand fitting operation, so that it does have its particular pattern of microscopic marks.
The bolt face of the 139 rifle I have photographed and enlarged in this photo graph to show the types of marks I was referring to.

Mr. Eisenberg.

You took this photograph yourself, and it is a photograph of the belt face of the 139 rifle?

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 belt-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 belt also, as it comes out of the rifle with the slot shown as a groove on the