Mr. Eisenberg. That will be 566, Mr. Reporter.
(The item so described was identified as Commission Exhibit No. 566 and received in evidence.)
Mr. Eisenberg. Mr. Frazier, could you discuss photograph 566?
Mr. Frazier. This exhibit shows on the left side of a dividing vertical line representing the top of the prism in the microscope which was used for the comparison, a portion of the surface from the test bullet from the rifle, 139, and on the right side of the photograph a portion of the surface of the bullet, 399.
The marks shown in the photograph are on an area representing approximately one-half of one groove impression in the barrel of the weapon, which extends from approximately 2 inches up from the bottom of the photograph, being the edge of one land impression, and the beginning of a groove impression, up to the top of the photograph, that area being approximately one-half or possibly two-thirds of a groove impression.
The microscopic marks which were used in the identification, after being observed through the microscope and making the comparison and the identification, were photographed, and this photograph shows a portion of the surface of that bullet, showing parallel lines extending from the left side of the photograph coming up to the hairline and continuing across on the right side of the photograph, these microscopic marks being very fine grooves and ridges on the surface of the bullet, very coarse ridges on the surface of the bullet, and inbetween size scratches left on the bullet by the barrel of the weapon.
There will be some marks which will not show up on one bullet which show up on the other bullet, and similarly some marks on the other bullet, in this case Exhibit 399, will not be present on the test bullet, that stiuation being due to a number of causes.
One, the bullets could have originally been slightly different in diameter, the larger bullet, of course, picking up more marks during its passage through the barrel.
Secondly, the two bullets may not have expanded exactly the same, due to the pressure of the powder behind them as they passed through the barrel.
Third, with each bullet fired through the barrel, there are certain changes that occur due to the wearing away of the surface of the metal of the barrel, so that after a series of shots through a particular barrel, it would be expected that the pattern of microscopic marks produced by it would change.