(Testimony of Robert A. Frazier Resumed)
Mr. Eisenberg.
There was no blood or similar material on the bullet when you received it?
Mr. Frazier.
Not any which would interfere with the examination, no, sir. Now there may have been slight traces which could have been removed just ,in ordinary handling, but it wasn't necessary to actually clean blood or tissue off of the bullet.
Mr. Eisenberg.
Did you examine this exhibit to determine whether it had been fired in Exhibit 139?
Mr. Frazier.
Yes, sir.
Mr. Eisenberg.
And what was your conclusion?
Mr. Frazier.
It was. Exhibit 399 was fired in the rifle 139.
Mr. Eisenberg.
That is to the exclusion of all other rifles?
Mr. Frazier.
Yes, sir.
Mr. Eisenberg.
Can you describe the types of markings which are generated onto a bullet, as opposed to those which are generated onto a cartridge case?
Mr. Frazier.
A bullet when it is fired picks up the marks of the barrel of the weapon. These marks consist of rifling marks of the lands and the grooves, the spiral grooves in the barrel, and, in addition, the abrasion marks or rubbing marks which the bullet picks up due to the friction between the barrel and the surface of the copper jacket on the bullet, or if it is a lead bullet, with the lead.
Mr. Mccloy.
You said the marks of the groove. You mean the marks of the groove or the marks of the lands?
Mr. Frazier.
Both, sir; both are present. In this barrel there are four lands and four grooves. Each of the raised portions in the barrel will be impressed into the surface of the bullet causing four--we call them land impressions--on the bullet, and, in between, four groove impressions.
Mr. Eisenberg.
How are you able to conclude that a given bullet was fired in a given weapon to the exclusion of all other weapons, Mr. Frazier?
Mr. Frazier.
That is based again upon the microscopic marks left on the fired bullets and those marks in turn are based upon the barrel from which the bullets are fired.
The marks in the barrel originate during manufacture. They originate through use of the gun, through accidental marks resulting from cleaning, excessive cleaning, of the weapon, or faulty cleaning.
They result from corrosion in the barrel due to the hot gases and possibly corrosive primer mixtures in the cartridges used, and primarily again they result from wear, that is an eroding of the barrel through friction due to the firing of cartridges, bullets through it.
In this particular barrel the manufacturer's marks are caused by the drill which drills out the barrel, leaving certain marks from the drilling tool. Then portions of these marks are erased by a rifling tool which cuts the four spiral grooves in the barrel and, in turn, leaves marks themselves, and in connection with those marks of course, the drilling marks, being circular in shape, there is a tearing away of the surface of the metal, so that a microscopically rough surface is left.
Then removing part of those marks with a separate tool causes that barrel to assume an individual characteristic, a character all of its own.
In other words, at that time you could identify a bullet fired from that barrel as having been fired from the barrel to the exclusion of all other barrels, because there is no system whatever to the drilling of the barrel. The only system is in the rifling or in the cutting of the grooves, and in this case of rifle barrels, even the cutters wear down as the barrels are made, eventually of course having to be discarded or re-sharpened.
Mr. Eisenberg.
Have you examined consecutively manufactured barrels to determine whether their microscopic characteristics are identical?
Mr. Frazier.
Yes, sir; I have three different sets of, you might say, paired barrels,. which have- been manufactured on the same machine, one after the other, under controlled conditions to make them as nearly alike as possible, and in each case fired bullets from those barrels could not be identified with each other; in fact, they looked nothing at all alike as far as individual microscopic
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