Mr. Cunningham.

burns, which actually cause the bullet to move forward--the pressure builds up behind it, and the bullet goes forward.

Representative Boggs.

That is a very good explanation. Thank you.

Mr. Eisenberg.

Mr. Cunningham, I wonder whether you could review the pictures with us, and discuss some of the markings which you found in those pictures that led you to decide that the cartridge cases shown therein have been fired in the revolver we have been discussing.

Mr. Cunningham.

Yes. The first photograph is a photograph of the breech-face marks, the individual characteristic marks remaining on test cartridge cases obtained from the revolver, and on the C-50 cartridge case that was recovered from the scone. C-50 is on the left. C-15 is on the right. And the hairline, the magnified hairline down the center separates the two cartridge cases.

Mr. Eisenberg.

Now, is the invariable procedure to put the test cartridge on the right and the suspect cartridge on the left? Or at least is that your standard procedure?

Mr. Cunningham.

I usually put the suspect on the left.

Mr. Eisenberg.

Well, in the photographs at any rate, in all the photographs we are going to see, the test cartridge is on the right, and the suspect cartridge is on the left?

Mr. Cunningham.

Usually.

Mr. Eisenberg.

And what is the magnification of this photograph?

Mr. Cunningham.

It is approximately 91 times.

Mr. Eisenberg.

Could you go on, please?

Mr. Cunningham.

Yes. On the left you will see the stamping, "SP", which is in the cartridge case itself. And over here next to the hairline you will see the individual characteristic marks. And you will see similar marks continuing on the other side of the hairline.
On the C-15, the revolver side, you will see a dark portion running vertically down through. That is the space that the Congressman was asking about--how it fits the primer. That is the small space at the top where the primer fits into the base of the cartridge. And over here to the right of that dark mark you will see a lighter colored object with more individual characteristic marks, that is actually the primer, the individual characteristic marks on the primer of the test cartridge case.

Mr. Eisenberg.

Now, as I understand it, in effect this picture can be viewed as a composite cartridge? That is, the picture on the left begins where the picture on the right ends, in terms of position on the cartridge case?

Mr. Cunningham.

In essence; yes.

Mr. Eisenberg.

And the point of the picture is to show that when you make this composite, the lines on each case show up as if there were no composite at all, but as if they were simply one case, because they are so close together in microscopic markings?

Mr. Cunningham.

Yes; in proximity. And they are brought together.

Representative Boggs.

And so similar?

Mr. Cunningham.

Yes.

Representative Boggs.

What is the magnification again?

Mr. Cunningham.

That is approximately 91 times.

Mr. Eisenberg.

Are there any dissimilarities on the two--on the test and the suspect cartridge cases, Mr. Cunningham?

Mr. Cunningham.

Yes, sir; there are always dissimilarities. However, the similarities so outweigh the dissimilarities that it is an identification. If there are no dissimilarities, I would be suspicious that it would be faked--using the same photograph and just cut and put together.
There are always dissimilarities.

Mr. Eisenberg.

Can you explain why there are always dissimilarities when the two cartridge cases are fired in the very same weapon?

Mr. Cunningham.

The metal is different; one cartridge case is slightly harder than another; for some reason the cartridge case wasn't driven back, upon firing, into the breech face exactly the same way. In other words, these marks are reproducing, but you don't get exactly the same hit. It would not be possible to get exactly the same hit time after time with different cartridge cases.