The main purpose of firearms identification is to determine whether a particular bullet, cartridge case, or other ammunition component was fired from a specific firearm. To do this, the firearms examiners at the RISCL utilize a large variety of physical and chemical techniques to perform examinations with an array of equipment. This equipment includes bullet recovery systems, comparison microscopes, scales, Mikrosil casting material, calipers, cameras, and trigger pull gauges.

The scientific basis behind firearms examination is the theory of toolmark identification. That is, during the interaction of two objects, the harder object (the firearm) will leave a mark on the softer object (ammunition components). Using a comparison microscope, the firearms examiners at the RISCL examine and compare striations, in order to make conclusions as to whether or not particular ammunition components were fired from a specific firearm.

In addition to firearms identification, the examiners in the RISCL Firearms Section regularly perform serial number restoration, tool mark comparison and identification, fracture match identifications, and shooting incident reconstruction.