Firing test bullets

In firing test bullets it is good practice to use the same make of ammunition as that submitted as evidence, preferably ammunition taken from the gun itself when confiscated or in possession of the suspect. This will not only help to assure similarity, which often is important because of variations in the same brand as well as in different brands, but it will also meet the objections of opposing counsel who will very likely raise the question as to the similarity of test ammunition. If one does not obtain good matchings when using similar ammunition it is of course permissible to experiment with other makes of ammunition to see whether better matching of markings can be obtained. If they can be so obtained, they are good evidence because they could not be produced by any other gun, no matter what ammunition was used. Bullet markings are influenced not only by the presence of rust, particles of grit or other foreign matter, metal particles torn off bullets previously fired, etc., but also by the material of the bullet and coatings thereon. Bullets made from highly hardened lead will show markings somewhat different from those made from soft lead. Bullets made from zinc or solder would show little evidence of rifling marks. Lubaloy-coated bullets will show markings different from those on plain lead bullets.

Some investigators recommend that reduced powder charges be used to get test bullets, particularly when high powered cartridges are being fired, maintaining that the markings on bullets are not affected by the strength of the charge. Some have even resorted to pushing bullets through a barrel to get test bullets. Others view the matter very differently. Certainly wherever test bullets of suitable quality can be obtained by not reducing the charge the normal ammunition should be used. It is felt that a reduced charge should be used only in those cases where it is absolutely impossible to get a satisfactory test bullet otherwise, and one probably never should resort to pushing bullets through the bore for the purpose of getting a test bullet.

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