Firearms Section at the Rhode Island State Crime Laboratory
receives and examines evidence related to firearms, firearm
components, ammunition, and ammunition components.
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.
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
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.