Firearm identification includes the identification of bullets, knowledge of weapons, the detection of gunpowder on garments and hands, and estimations of bullet trajectory and distance. As the number of shootings and crimes involving guns has increased, the area of firearm identification has increased in importance.
The reason for this is that a gun barrel is produced by drilling out a solid cylinder of steel. This drilling produces striations or marks on the inside of the gun barrel or bore. In addition, each gun is given spiral grooves by the manufacturer. This is known as rifling or spiral grooves cut into the barrel of a gun in order to make a bullet spin as it is fired. Rifling produces grooves (the low areas cut into the barrel) and lands (the raised areas between the grooves). The diameter of the gun barrel is known as the caliber. A gun’s caliber is typically measured in millimeters or one hundredths of an inch. For example, a gun might have a caliber of .38 or 9 millimeter. Each manufacturer produces a particular pattern of grooves in the barrel, which also produces class characteristics for a type of gun.
This would indicate that the same gun was used in two crimes. The Integrated Ballistic Identification System (IBIS) is a database of digital images showing the identifying features of bullets and casings. It was created for the Bureau of Alcohol, Tobacco, Firearms and Explosives in the United States. In 1999, the National Integrated Ballistic Identification Network (NIBIN) was created by the FBI and the ATF using the IBIS. This network provides law enforcement agencies around the world with access to the images and information. The network has provided law enforcement officials with thousands of matches in the decade that it has been in use.
A distance determination is the process of estimating the distance between where a shot is fired and its target. This is often done by looking at the patterns of powder residue and the shot pattern. When a gun is shot, traces of gunpowder travel out of the barrel of the gun with the bullet in the direction that the bullet is traveling in. If the end of the gun or muzzle is close to the target, some of this gunpowder residue will be transferred to the target. The pattern or distribution of the residue helps forensic scientists estimate the distance of the