iKAPOW / May 2014 13
Identifying a Firearm
Gross Differences: The first thing a scientist will do when attempting to identify a firearm is to check that the bullet is of a caliber that could have been fired by the firearm.
Rifling Impressions: Scientists will then proceed to determine if the rifling impressions found on the bullet match the pattern of rifling contained in the barrel of the firearm. These patterns, specifically the fine grooves, are called striations. Striations are examined because they have the potential to be consistently reproduced in a unique pattern on every bullet that passes down the barrel of a firearm. Identification can be proved even further by examining not only the class characteristics, but also the individual characteristics of the markings.
lBreech Markings: Scientists will also examine breech markings made on the cartridge case and match them to marks in the chamber and breech.
Microstamping: Microstamping is a newer technology that utilizes lasers to make precise, microscopic engravings on the internal mechanisms of a gun. When the gun is fired, the unique alpha-numeric code identifying the gun's make, model, and serial number is stamped onto the cartridge case. While his makes the bullets easily identifiable, not all guns are created with this technology.
Crissy Kempf
Each firearm's barrel contains small ligatures and grooves, which, when a bullet is fired from it, make marks on the cartridges, bullets, and shell casings. Scientists will carry out distance and depth tests, which include firing rounds of ammunition into water, sand, and other substances to find the patterns that gun will make on its bullets, shell casings, and cartridges. These patterns will then be closely examined under a macro-scope in an effort to find a match.