Ballistics in Forensics - Caliber vs Gauge

When CSI's approach a crime scene and find a bulletintact, the police can determine the caliber by simply
with a certain caliber or gauge, just exactly what aremeasuring it. Severely damaged and deformed bullets
they talking about? In this article, caliber and gaugeare weighed for the purpose of excluding some
will be defined to educate the reader so that thecalibers but not for determining the exact caliber. For
next time you watch your favorite CSI TV show,instance, the weights of .22 caliber and .44 caliber
you will know what they are talking about.bullets differ slightly. Many times, forensic scientists
What is a caliber?can find out whether the bullet contains a jacket. If
Caliber is a term used toward firearms such asso, what kind of jacket? Making this determination
handguns and rifles. The caliber of a firearm refers tohelps to identify the bullet type and ultimately the
the size of the internal diameter of its barrel. Calibersweapon type used in a crime.
of handguns and rifles are measured in millimeters orThe shotgun pellets, or lead balls, from a shotgun can
inches. A .25 caliber handgun has a barrel with anbe removed from the victim during surgery or
internal diameter of 0.25 inches or ¼ of anautopsy and from floors, walls, and other places. The
inch.size of the shot does not necessarily tell you the
What is a gauge?gauge of the shotgun but rather provides information
Gauge is a term used toward shotguns. The gaugeabout the ammunition used. The different sizes of
of a shotgun also reflects the size of the internalshot are numbered. The smaller the number, the
diameter of the barrel. However, this size is not alarger is the size of pellets inside the shotgun shell.
direct measurement. Rather, the gauge of a shotgunFor instance, Number 7 shot is smaller than Number 4.
is determined by counting the number of lead ballsPellets differ in size from 0.05 inches for Number 12
matching the barrel's diameter that it requires toshot to 0.33 inches for 00 shot, the biggest, which
weigh one pound. Therefore, it takes 20 lead balls toalso goes by the name "double-O" buckshot. A
fill the diameter of a 20-gauge shotgun barrel and toforensic ballistics examiner measures the diameter of
weigh one pound.any shot found and ascertains what size shot was
The caliber and bullet type are crucial in ascertainingused.
what firearm was used in a crime. If the bullet is