Firearms are a deadly efficient weapon and are commonly used to harm by individuals to harm others. Even with Australia’s relatively strict gun laws there is still a significantly high number of crimes involving firearms which therefore requires a forensic team to have a good knowledge in firearm analysis and identification. In a firearm related crime the complete identification of a firearm often requires the forensic officer involved to determine the make or manufacture, type, caliber or gauge, serial number, model, barrel length and number of shots it has the capacity to fire. They must also be able to determine the distance at which the weapon was fired (range) and analyze primer and gunpowder residue deposits in order the identify and convict suspects.

The most common task of a firearm examiner is to link a bullet back to the weapon it was fired from.

The class characteristics of a firearm are the features that identify the make and model. These characteristics must be determined to link a bullet back to what it was fired from. The barrel of a firearm is manufactured by a step know as rifling (Rowe, 2000). Th

In the case of shotguns testing the unique characteristics left on the cartridges is achieved in a different way. Unlike rifled firearms, a shotgun has a smooth barrel therefore there will be no striations left on of the shot pellets fired. In determining the size of a shot fired, the forensic officers can weigh the shot material recovered from the crime scene (Saferstein, 2001). A shotgun operates by pulling the trigger, which releases the firing pin, causing the firing pin to strike the primer, which then ignites the powder. The metal on the cartridge case is relatively soft and will exhibit unique imprints from the firing pin. If recovered these cartridges can by linked back to the shotgun in the same fashion as bullets are. The breechblock (rear part of the firearm barrel) will also leave permanent markings on the end of the shell due to the rearward thrush of the shell when it is initially fired (Saferstein, 2001). By analyzing these markings clues are given to the type of make and model of the shotgun in a similar fashion to the process of examining the markings left on bullet casings.

is involves impressing its inner surface with spiral grooves. The original surfaces, or bore, between the grooves is referred to, as lands and they are at equal distance apart. The diameter between the lands of the barrel is the called the firearms caliber. Different makes and models of firearms will have different caliber’s, different directions of twists in the groove and a different number of lands and grooves. For example, Marlin rifles are rifled by a unique process called microgrooving resulting in 8 to 24 grooves impressed into their barrels. As a bullet is made slightly oversized for the barrel in which it is to be fired out of it will bare an imprint of the number of lands and grooves of the barrel and the direction and degree of the twist of the grooves (Rowe, 2000). If a bullet is undamaged this can easily be determined by simple inspection.

After the weapon has been fired gunpowder residue is also blown back onto the shooter. If a suspect is located and taken into custody it can be determined if

Some topics in this essay:
Analysis Firearms, Electron Microscope, saferstein 2001, rowe 2000, weapon fired, gunpowder residue, primer residue, firing pin, propellant particles, fired weapon, forensic officer, metal crystals, firearm related crime,