Firearms identification is a discipline in Forensic Science and their primary concern is to determine a spent projectile, fired casing, or another ammunition component was fired from a particular firearm or from the same firearm. Comparison can be made between evidence (projectile, fired casing, or other ammunition components) or between evidence and test made with a submitted firearm. Forensic Chemistry aids firearm examiners in cleaning corroded bullets and cartridge cases. Chemistry aids in serial number restorations and also in analyzing gunshot residues.
The firearm is designed or can be readily converted into expelling a projectile by the action of an explosive.
There are two basic types of firearms
- Long guns
A handgun is a firearm designed to be held and fired with one hand and it involves pistols and revolvers.
Pistols refer to a handgun which when the trigger is pulled, fires, eject the spent casing, loads a fresh cartridge from the magazine, and cocks the action by retracting the coil from the fresh cartridge. In pistol, singe chamber is aligned with a single bore supported by a short stalk.
A revolver is usually a handgun with a cylinder having several chambers rotating around a central axis and will be discharged successively by the same firing mechanism.
A long gun is a firearm designed to be held and fired at the shoulder with both hands. Long guns typically involve Shotguns and Rifles.
A shotgun refers to a smooth bore shoulder arm designed to fire shotshells containing numerous pellets or sometimes a single projectile. The most encountered shotguns are a) pump-action and b) semi-automatic shotguns are shown below.
The term Rifle refers to a firearm having a rifling in the bore and designed to be fired from the shoulder. Encountered rifle designs are a) Bolt action, b) lever action, c) semi-automatic, and d) pump action.
Germans introduced a new class of small arms called ‘strumgewhr’ or assault rifle that has been introduced in the 1939-1945 war era.
Assault Rifle is a compact select-fire detachable magazine-fed weapon that utilizes a center rifle cartridge and is for military use.
Submachine gun refers to an automatic or select-fire weapon most commonly firing pistol-caliber ammunition.
Machine gun refers to an automatic firearm that fires most commonly rifle caliber ammunition supported from a tripod or other support.