NOTES ON CRIMINALISTICS
FORENSIC BALLISTICS
Ballistics is the science of the motion of the projectile and the condition that affects their motion.
It is a science in itself for it is an orderly arranged knowledge, which is a product of series of
experimentation, observation and testing. Ballistics is not an exact science rather it is applied physics
or applied science, which is subject to changes and improvement depending upon the demands of the
modern civilization. Motion refers to the mobility or movement of the projectile from the time it leaves
the shell empty, it leaves the gun muzzle and until it reach its target or fall in the ground. A projectile
is any metallic on non-metallic ball which is propelled from a firearm. Its motion can be categories into
three general types: Direct motion, Rotatory motion and Translation motion.
3 Types of Motion
1. Direct Motion = is the forward motion of the bullet or shots out of the shell by the
action of the expansive force of gases from a burning gunpowder.
2. Rotatory motion = is the action of the bullet passing through a rifled bore barrel
firearm which is either twisted to the left or to the right.
3. Translational = is the action of bullet once it hits a target and subsequently
ricocheted.
Origin of the Word Ballistics
The word Ballistics was derived from two Greek words. The word “ballo” and the word “ballein”
which literally mean, “to throw”.
The term also said to have been derived from the Roman war machine called “Ballista”, a gigantic
catapult that was used to furl missiles or large object at a distance like stone, dead animal or even dead
person.
The study of Ballistics in the early age is divided into (3) three Divisions: Internal Ballistics, Exterior or
External Ballistics and Terminal Ballistics. From the time the gun was fired until it reach the target and
have its maximum effect. At present ballistics is branches into four (4) and this is due to its subsequent
used in solving problems in connection with the administration of justice particularly cases involving
firearms and ammunition which is termed as Forensic Ballistics.
Branches of Ballistics
1. Interior (Internal) Ballistics = it treats of the motion of the projectile while it is still inside the firearm
(chamber /barrel) which extends from the breech to the muzzle. The conditions attributed to internal
ballistics are as follows:
a. Firing pin hitting the primer b. Ignition of the priming mixture
The priming mixture (composing of the KCLO3, sulfur and carbon) located either at the
cavity rim or at the center of the primer upon the striking effect of the firing pin will ignite and
such action is known as “Percussion action”.
c. Combustion of the gun powder/powder charge or propellant.
d. Expansion of heated gas.
