Chapter 1

Ballistics And Its Branches

What is ballistics?

 is science of the motion of the projectile and the condition that affects its motion.

BALLISTICS AS SCIENCE

 for it is a knowledge, which is a an product of orderly arranged a series of

BALLISTICS AS AN APPLIED PHYSICS

 for it studies the motions of the projectile such as its velocity, trajectory, approximate
range, power, resistance to air and other circumstances that affects its travel.

MOTION

refers to the mobility or movement of the projectile from the time it leaves the empty shell; it
leaves the gun muzzle and until it reaches its target or falls on the ground.

PROJECTILE

A projectile is a generic term which refers to any metallic non-metallic ball or propelled from
firearm.

NOTE:

Technically, all projectile a propels from small arm that is is called "bullets" with the exemption
of a shotgun projectile which is referred to as "shots or pellets". To the policemen, the term
bullets are commonly referred to as "slugs". Projectiles that are in artillery firearms, too big and
even designed for explosions are aptly called "missiles".

THREE TYPES OF MOTION IN PROJECTILE

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 o the
left or to the right.
3. Translational Motion

is the action of bullet once it hits an object or the target and subsequently ricocheted (changes in
motion).

BALLISTICS

Derived from two Greek words "ballo" or "ballein" meaning to " To THROW"

NOTE:

The term was also said to have been derived from the Roman war machine called " ", a gigantic
catapult that was used to hurl missiles or large objects like stones, dead animals or even dead
persons at a distance.

BRANCHES OF BALLISTICS

The study of Ballistics was initially divided into (3) three Divisions:

Internal Ballistics, External Ballistics and Terminal Ballistics

These encompass the time from which the bullet is fired from the gun until it reaches the target
and has its maximum effect.

Due solving to the cases current application of Ballistics in involving the use of firearms and
ammunitions, a fourth branch has emerged, namely, Forensic Ballistics

1.Interior (Internal) Ballistics is that branch of ballistics which 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 Upon the squeeze of the trigger, the hammer will be released
which causes the firing pin to be pushed and hit the base portion of the cartridge where the
primer is located.

b. Ignition of the priming mixture (Percussion action) The priming mixture (composing of the
KCL03, 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.

c. Combustion of the gun powder/powder charge or propellant. After the ignition of the priming
mixture, the ignition is imparted to the gunpowder by passing through the vent or flash hole, thus
burning the gun powder and converts it into an expanded hot gas.

d. Expansion of heated gas. Once burned, the charged powder is converted into a heated gas, and
due to a more elastic property of gases, its particles will spread and fill the entire container
(cartridge case/shell).
e. Pressure developed. The outward push of the gases to the burned powder pressure is
developed due to the great amount of gas that is expanding within the shell causing the
withdrawal of the bullet from the shell.

f. Energy generated. Energy is the capacity to do work. The potential energy serves as the
propellant of the expanded gases, inasmuch as the pressure that is developed has that degree of
energy to force the projectile out of the Ballistics it is the measure of force in foot-pound shell
necessary for an action.

g. Recoil of the Gun This is the equal and opposite reaction of the gun against the forward
movement of the bullet upon explosion. The backward or rearward movement of the gun in
relation to the forward movement of the bullet may be divided into two divisions: The first,
which occurs while the bullet is still inside the barrel and which is relatively small in intensity;
and the second, which occurs just after the bullet leaves the muzzle of the gun and this is a more
violent backward impulse when the hot gasses rush up and out of the muzzle and set against the
gun. Another reason and which is of greatest influence in the recoil of the gun is the firing
mechanism of the gun. These mechanisms are generally categorized as: the blow back type, the
gas operated, and the recoil operated, or a combination of gas and recoil operated. Among this
firing mechanism, the blow back type has the lesser recoil and this can be observed in firing a
pistol

Jump is another portion of the recoil action that is characterized as the backward and
upward movement takes place before the bullet leaves the muzzle.

h. Velocity of the bullet inside the barrel It is the relative speed of the bullet per unit of time
while it is still inside the barrel or at which it leaves the gun muzzle.

i. Rotation of the bullet inside the barrel It refers to the twist of the bullet caused by the
cylindrical grooved portion of the barrel of most firearms. In some instance, this condition may
not be possible especially when the bullet passes through a smooth bore barrel,

j. Engraving of the cylindrical surface of the bullet Once the bullet has passed through the barrel
of any firearm be it rifled (with cylindrical groove cut) or smooth bore, whatever imperfections
interior barrel of the gun has will be impressed and left or on the cylindrical surface of the bullet
serving as its scratches the thumbprint. This becomes one of the most valuable marks that would
serve as its individuality.

2. Exterior (external) Ballistics treats of the attributes or movement of the projectile after leaving
the gun muzzle. It is extended from the muzzle of the gun to the target or any attributes to the
motion of the projectile while it is in its flight and before reaching the target.

a. Muzzle Blast It refers to the noise created at the muzzle point of the gun brought by chemical
reaction between the expanded gases and the air outside. Given that most propellant is composed
of compounds of nitrates, it produces the accompanying loud once these are burned and mixed
with the air where oxygen, carbon, hydrogen, and other gaseous maters are present.
b. Muzzle Energy Energy generated at the muzzle point measured in foot-pound. This is
attributed to liberating at the muzzle point.

c. "Trajectory the hot gas" This refers to the parabola-like flight of the projectile from the time it
leaves the muzzle until it hits the target. It is also described as the actual curve path taken by a
bullet during its flight. A trajectory has three (3) stages when bullet is fired to its maximum
range. These are: The straight travel or the stage at which the bullet travel straight or maintain its
accurate travel (gyroscopic action), the curving of the bullet in flight due to the gradual lost of its
energy, and the drop of the bullet to the ground due to its weight and upon reaching the
maximum distance of its travel and it hits nothing. The trajectory plays an important role in the
investigation of shooting incidents for it gives reference to the possible position of the shooter in
relation to the target. This is associated to the point of entry and exit of the bullet.

d. The range refers to the imaginary straight distance from the muzzle of the gun to the target.

Accurate Range the distance within which the shooter or gunner has control of his shots.

Effective Range the distance within which a bullet is still capable of inflicting injury after it has
been fired.

Maximum Range the distance that a projectile can be propelled from a firearm. The farthest
distance the bullet could travel.

e. Velocity This refers to the rate of speed of the bullet (during its flight) per unit of time, and it
is usually expressed in feet per second (ft/sec) and measured through the use of a chronograph
machine. The velocity of a bullet fired upward has an equal velocity downward due to the
principle of the gravitational pull. They only differ in direction and transformation. A bullet fired
upward has its maximum velocity upon leaving the muzzle and little by little loses its power and
velocity as it moves upward. While the bullet that falls downward after reaching its maximum
heights has an increasing velocity as it goes downward.

f. Pull of Gravity This is the downward reaction of the bullet towards the earth surface.due to its
weight. This is based on the principle that anything that goes up must goes down.

g. Air Resistance It is the force of the air encountered by the bullet in its flight. A slow moving
object occupies smaller space at a given time while a fast moving object occupies larger space in
just a short time. Thus, since bullet travels fast it encounters more air than a running man.

3. Terminal Ballistics is that branch of Ballistics that deals with the effects of the projectile's
impact on the target.

a. Terminal Accuracy It refers to the size of the bullet grouping on the target. A bullet grouping
that is bigger has a lesser chance to produce substantial damage, hence lowering its chance to be
lethal. On the other hand, the smaller the size of the bullet grouping on the target, the more
accurate and effective the shot become.
b Terminal Energy It is the energy or force of the projectile when it strikes the target. A bullet of
a smaller caliber has lesser energy though it penetrates greatly into the target.

c. Terminal velocity It is the speed of the bullet once it strikes the target and penetrates it.

d. Terminal Penetration It is the depth of the bullet's entry into the target.

When a projectile hits its target, terminal ballistics phenomenon that occurs may be one or a
combination of the following:

1. Indentation

2. Penetration

3. Perforation

4. Ricochet

5. Fragmentation

6. Detonation and other related blast phenomena

7. Combustion and Incendiary effects

4. Forensic Ballistics This branch of ballistics is the product of the application of the ballistics to
law. The idea comes with the use of the word forensic. The word Forensic was derived from the
Latin word "forum" meaning a "market place where people gathered for discussion. public
disputation or public

When used in connection with the word ballistics or other natural science, it suggests a
relationship to the courts of justice or legal proceedings. (Forensic Ballistics is defined as the
study of the motion of the projectile science of firear applied to law or simply the identification
by means of the ammunition fired through them.

SCOPE OF FORENSIC BALLISTICS

1. FIELD INVESTIGATION

✓ work of the first officer on the case on the field

✓ It is primarily a routine job of investigating officer. Such work includes recognition,

✓ in coordination with the Scene of the Crime Operation Unit (SOCO).

2. BALLISTICS TECHNICAL EXAMINATION OF THE EXHIBITS

✓ Its scope covers the marking of evidences, test-firing (to obtain test bullet and test shell in case
a suspected firearm is recovered), examination of ballistics exhibits using caliper, bullet
comparison microscope and other scientific instruments, preparation of comparative chart and
reports on the findings and conclusions as regards to the examination undertaken.

3. LEGAL PROCEEDING

This is the last and yet one of the most critical part in the field of firearm identification. Here the
examiner has to go to court and testify as an expert witness regarding the ballistics examination
and report that he/she has prepared. It is also in this stage that the qualification and competence
and expertise of the examiner is determined and tested.