Introduction

BALLISTICS comes from the Latin ballista, a type of catapult, from the Greek bállein (to throw),
17th century, the art of launching projectiles, used for defense and attack.

It is the branch of Criminalistics and Forensic Science that is responsible for the study of the
firearms, the phenomena at the moment of firing, the casings
hit by the projectiles fired, of the trajectory of the latter and of the
effects they produce.

Ballistics studies the movement of projectiles, their displacement, and the effects.
that are produced in the impacted white, in their study it is also observed those
phenomena that occur within firearms; forming part of physics
(kinematics) and chemistry. While ballistic science plans weapons and
ammunition used to produce a specific effect on a target; forensic ballistics
acts in the reverse sense, that is, from the effects produced on the target by the projectile
It must be determined what weapon and what ammunition were used.

Forensic ballistics encompasses the study and analysis of projectiles and impacts.
determining the caliber of the firearm discharged; It also concerns determining the
correspondence between projectiles or casings found at the scene of the incident
with some weapon found in the possession of a suspect or at the scene of the event
criminal; likewise, it verifies the presence of gunpowder residues on the target, with the
object of obtaining an approximation of the distance from which the shot was fired.

Provides essential knowledge for clarifying punishable conduct

in which firearms have been used, allowing to determine the
specific qualities of the weapon involved in the incident, the type of ammunition used, the
injuries caused to the victim, the damage to objects, the determination and
reconstruction of trajectories, the origin of the projectiles and recovered casings
at the crime scene, during the investigation or the necropsy, allowing to obtain
a clear vision of the sequence of the
facts and the establishment the possible authorship of
crime.
 Historical background
In the 18th century, there was still no police force as such in London, in the city of
In Westminster, there was a Justice of the Peace named Henry Fielding who succeeded him,
later, his assistant and brother John Fielding. Henry recruited a small group
From "assistants" in 1749, they were directly assigned to his charge, representing the
beginnings of the current police methods. They were known as the Bow Street
Runners were dedicated to investigating small-scale organized crime.
scale using, at first, unorthodox methods and even, some other one
sometimes, methods not very legal.

The first successful attempt recorded occurred in the early century

XIX, upon discovering the author of a crime committed with a firearm. In 1835,
Henry Goddard, one of these 'peculiar researchers', while observing a projectile
extracted from the body of a murder victim, he noticed the existence of a
striking protrusion or bulge on it. As in that time the weapons of
the fire was of breech-loading and the shooters typically made their own projectiles
with molten lead using a mold or turquoise, our seasoned investigator thought
that if I found the mold with which the projectile was made, I would find the
murderer. With this idea, Goddard began to record the houses of the suspects and,
when I was proceeding to register the home of one of them, upon examining the mold with the
that the owner manufactured lead projectiles, our experienced
the researcher was able to clearly observe that inside the turquoise there was a
small notch. Using this mold, he proceeded to manufacture a new projectile.
(witness) and compared it with the one extracted earlier from the victim's body
(doubted), verifying that the bulges of both projectiles were identical without
place for doubts, which caused the killer to later confess his crime.
Starting in this way a new research method.

In Germany, during 1898, Doctor Paul Jeserich attended as an expert for

advise the court of the city of Neuruppin in a murder case. During the
process, they showed him a projectile that had been extracted from the victim's body and a
revolver that belonged to the accused. Jeserich was in favor of the theory that established that
a projectile suffered a series of injuries while traveling through the bore of a weapon's barrel, due to
the contact of this with the grooves of the cannon, with great pressure, which would be equal in
all the projectiles fired with that same weapon; and proceeded to make a shot
for testing, photographed the two projectiles, the one extracted from the victim's body (doubted)
and that obtained through a shot with the weapon (witness, sample or accused), expanded
the photos and confirmed that the injuries left by the stretch marks and the fields of the soul of
the cannon in the "witness projectile" was identical to that of the "debited projectile".
confirming the theory and being able to punish the guilty.

In the 20th century, other researchers were developing new research methods.
which, gradually, would be made known in their advisories to the courts of
justice. Richard Kockel, being the director of the Forensic Institute of Leipzig (Germany),
He carried out the first tests of the 'development' of a projectile body.
negatives of this on wax plates and zinc oxide. Professor Balthazard was given
It is said that there were a series of marks on the end of the sheath and that these were
produced by the striking needle at the moment of firing. Also the
The chamber was producing injuries on the cartridge base and even the extractor claw and the
the expeller left characteristic marks on the casing, which could serve to
identify a weapon. But these investigations had to be abandoned due to the
beginning of World War I.

Charles E. Waite, one of the greatest pioneers of forensic ballistics, began to

visit the most important arms factories in the U.S. and later the
Europeans, requesting the exact data on the characteristics of the weapons that
they were manufactured. This idea arose from attending -in his capacity as an official of the
Public Prosecutor's Office of the State of New York - as an assistant to the President of the
Investigation Commission by the state governor; this commission was in charge of
to review the sentence issued by a court in Orleans Parish, remaining very
impressed by the events and promising himself that he would try to achieve a
reliable method that would allow for the identification of a weapon through the examination of a cartridge.
It was the process that investigated and judged the case of the double murder committed in a
farm of the small town of West-Shelby, where its owner Charles B. Phelps and
his housekeeper, Margarett Walcott, were shot dead with a caliber gun
22. Two farm workers were accused and convicted in a trial with
various irregularities. Three projectiles were extracted from the body of Charles B. Phelps
of caliber 22. Albert Hamilton hired as a 'ballistics expert' by the prosecutor of
case, once the revolver found on one of the workers was inspected
(Stillow) and the projectiles, made a decisive report stating that in the
At the muzzle of the weapon, there was a notch that appeared marked on the projectiles.
this report served to establish that the projectiles could only be fired with the
revolver of the accused. Being sentenced to die in the electric chair. During the
case review, several test shots were made to obtain new
witness projectiles, which were sent along with the questioned ones, to the company
Bausch & Lomb optics, to search for the notches that Hamilton claimed to have found,
being unable to locate them either in the projectiles extracted from the corpse or in the
that were obtained in the test shots conducted. But an important was carried out.
discovery, the projectiles from the corpse and those from the test had five grooves, but
with a great difference, the grooves of Stillow's revolver were normal and regular, and
this could be seen in the projectiles obtained in contrast to the projectiles
extracted from the corpse (doubted) that showed a marked intermediate field of a
abnormal width. This undoubtedly determined that the weapon used for
committing the crime had a manufacturing defect that the weapon owned did not exhibit
de Stielow. He was ultimately declared innocent, but three years had elapsed in
prison and was about to cost him his life in the electric chair due to a false report from
a supposed specialist without scruples.
At the end of 1923, after four years of travel and intense work, he discovered that he did not
there wasn't a single model that was exactly the same as another, there were differences in the
calibers, in the number and orientation of the grooves, (oriented to the left 'left-handed' or to
right ('dextrorotatory') and its torsion angles could be different. He created a catalog
technician of most of the existing weapons at that time, but it was needed
find some 'individualizing characters' that would allow distinguishing weapons from
same type, brand, and model. Considering that the projectile passes through the barrel
from the cannon suffers two types of injuries: the first caused by the striations of the soul,
that in the projectile will turn into fields, and the seconds caused by the fields
from the soul of the cannon, which will result in the grooves on the projectile, we can say
that the projectile, after traveling through the barrel of the cannon, becomes the negative of
this. Here was the solution.

Waite asked Max Poser to build him a microscope equipped with a support for
keep the projectile subjected, and with a measuring scale that would allow measuring the
the most insignificant injuries that existed in him. Physicist John H. Fisher joined him and
the chemist and great specialist in microphotography Philipp O. Gravelle. Thanks to this
Union was born in New York, the world's first forensic ballistics institute, the Bureau.
of Forensic Ballistics. Fisher contributed two great inventions to the research.
transcendental in forensic ballistics:

An apparatus that was used to see in detail the interior of a gun barrel.
of fire (thus the helixometer was born).
A new calibrating microscope with greater precision that allowed measuring
the intermediate fields, the striations, and their orientation.
In 1925, Gravelle came up with the idea that would give ballistics one of its foundations.
most important scientists, joined two microscopes through an optical device by
in which two projectiles could be seen together in a single image and achieve that both
they will turn so that they could be compared by seeing the similarities and differences that
there would be in them. Dr. Calvin Goddard joined Waite's team, who, following the
the path initiated by Professor Balthazard began to observe the bottom of the pods
shootings, finding that the injuries caused by the machines used in the
manufacturing of the striking needle or the closure block of the weapon that had been carried out by the
The shots matched the injuries that appeared on the base of the cartridge case used.

Doctor Goddard collaborated in the important advances in the field of

ballistics, as the most complete ballistics database of its time, and the
establishment of the first independent forensic science laboratory in the
United States. Contributed to the investigation of numerous cases throughout the country.
collaborating with the police, among others, in the spring of 1927, in a process
controversial and not without irregularities, of Sacco-Vanzetti (the robbery of
Massachusetts); made known its observations, issuing a report with them.
model in the history of Forensic Ballistics. In 1929, in the investigation of the
St. Valentine's Day Massacre (in Chicago) the case concerning the murder of the
members of a band dressed as uniformed Chicago police.
Research has evolved, and considering the contributions
initials and principles of criminalistics, which establish that every instrument
mechanical or physical when pressing on a surface, the hardest leaves on the
softer its imprint or trace of class and identity that allows identification
also the tool in particular. With the help of the development of new techniques and
technological advances and more sophisticated instruments have been focusing on the
current state in the study of tool marks and has been called Toolmark.
These brands are unique and reproducible, this principle has been confirmed over decades
with numerous studies.

The most technologically advanced systems currently make it possible to

digital ballistic examination including even two-dimensional images of projectiles
and casings, this system allows scanning with a laser through a
specific application interferometer and generate high-resolution images in three
dimensions, which can be examined with greater precision and the guarantees
necessary that requires physical evidence for a report in less time and with
smaller margin of error, this system allows them to be analyzed through colorization
sensitive topography, movement of light sources, orientation.

Forensic ballistics has evolved since its inception and continues to do so without stopping;
its development is largely due to the application of technological advancements and to the
new instruments, as well as the people who have managed to find an application
useful for the analysis, discovery, and comparison of new evidence in a more
reliable.

Currently, advances in the fields of electronics, computing, software, optics,

Chemistry, physics, and genetics have allowed great advances in the field of ballistics.
forensic, analyzing with great precision any clues that allow for the resolution of the
cases.

Forensic Ballistics
It is the ballistics applied to criminalistics. Utilizing sciences such as physics,
chemistry, mathematics, and technical methods and criminalistic procedures that are
applied in the scene where a firearm has been used, as well as the study of
these and their cartridges, shells, and projectiles, with the aim of identifying the weapon
of fire employed, assisting in the research of police investigations and to the
judicial authorities for a good administration of justice, establishing the types
of injuries or impacts caused by the fired projectile, gathering the evidence and
other details of ballistic interest.

Forensic Ballistics is a relatively new science, with the first works dating back to
1912, when Professor Baltahazard from the University of Paris presented at the second
Congress of Forensic Medicine, on the identification of firearms, by their bullets,
through the photograph taken of the incriminating projectile and that of the fired evidence
with the suspicious weapon. The method was extremely expensive and the photographs were obtained
using a pantoscopic camera.

Currently, forensic ballistics is one of the branches of forensic sciences most

advanced and reliable that exist and focuses mainly on five aspects:

THE IDENTIFICATION OF THE WEAPON: "It consists of identifying the type of weapon
used (type, class, model, and brand) through the characteristics of the
shot projectiles and the struck casings." This is done by studying the shape
and dimension of the class characteristics presented by the projectiles and shells
(marks originated by the extracting claw, type of percussion, number and
orientation of the striations, etc.). If a projectile is obtained from the scene of the
crime, a series of striations will be observed along its surface, it must
check if these stretch marks, both in number as well as thickness and orientation of the
they match the striations of the bore of the suspicious weapon.
IDENTIFICATION OF AMMUNITION: It can be done by the casing
(marks of the firing pin and extractor), by the bullet (rifling) or by the type of gunpowder
(through microscopic examination and chemical analysis). The goal is to achieve
determine the brand and caliber of both the projectile and the casing.
THE CONDITIONS OF THE SHOT: The most important thing is to determine the
firing distance and the trajectory of the projectile, in order to find out where
the person who fired the weapon was found.
IMPACT SPEED, which determines the type of weapon and distance.

Initial velocity. - It is the velocity of the projectile at the moment that

abandon the mouth of the canyon. It is represented by the expression and is measured in
meters/second.
Impact speed. - It is the speed of the projectile at the moment of
collide with the white and determine the energy that will be transferred to it
body.
THE SHOOTING DISTANCE has special importance within the
forensic ballistics, which is guided by the presence or absence of various elements
characteristics of each of the distances:
Close-range shot: The shot is fired with the mouth of the barrel touching the
objective. Create a star-shaped entry hole, causes
an internal expansion of the tissues leaves shooting residues in the
interior of the body, etc.
Point-blank shot: The shot is fired at 30 centimeters or less.
The burn appears, caused by the flame that comes out of the mouth.
from the canyon. The “tattoo” produced by the
shot residues like burnt and unburnt gunpowder. Always
there will be an erosive collar, which is an abrasion on the skin caused by the
bullet shock. Sometimes a fence can also be found.
cleaning, produced by the dirt dragged by the projectile in its
route before reaching its goal.
Close range shooting: These are the shots fired at more than 30.
centimeters. It has the same elements as the close-range shot
except for the burn, and to determine the distance accurately there will be
to carry out test shots, examine the amount of waste that
they reached the goal, etc.
Long-range shooting: It is the one at which the elements that make up the
tattoo can no longer arrive, so there will be no tattoo. It usually starts from
more than one meter to the maximum range that the projectile can reach.
 Classification of Forensic Ballistics
INTERNAL BALLISTICS
Study, analyze, and evaluate the process developed by the action of the striker until the
Bala abandons the weapon and all the phenomena that occur inside a weapon.
of fire.

The pressure generated by the gases propels the

bullet, that abandons the sheath and penetrates into the
soul of the canyon. The bullet is located.
so with the helical nervations
characteristic of a rifled cannon that impart
a rotation movement around its own
e.g. Consequently, the bullet acquires the
translation and rotation movement on
its own axis before leaving the weapon.

Phases:

1. Percussion: Strike between the firing pin and the hammer, and this pushes the primer.

2. Initiation of the detonator: It is the relationship that occurs due to the impact (explosion of the
chemical substance) for this it is necessary for the anvil to exist, it is the counterforce of the
percutaneous needle.

3. Burning of the propellant: It occurs at a temperature of 320ºC to 480ºC inside the

cartridge.

4. Projectile motion.

5. Shearing: the striae of accommodation and rotation appear.

6. Abandonment of the projectile from the fire mouth.

7. Setback.

EXTERNAL BALLISTICS
Study the behavior of the bullet or projectile from the moment it leaves the mouth of the weapon,
during its trajectory and the factors that affect it, until it reaches the place of
impact.

Once the bullet has left the gun, a series of phenomena begins to occur.
during its flight towards the target that are studied by external ballistics. From the
the bullet
subjected to translational movement towards the target and rotation about its axis is affected
due to the resistance that the air opposes to movement and by the gravitational force.
air resistance reduces its speed while gravity makes it
deviate from its trajectory when attracted by the earth. Other factors also affect the
although its influence is significantly smaller, such as the direction of
wind, atmospheric pressure, etc.

With movements:

Parabolic: Resulting from the combination of the projectile's displacement and

the gravitational force exerted on it.
Measurable physical space existing between the muzzle of the weapon and
the site of impact.
Rotation: Spin of the projectile around its longitudinal axis, resulting from the force
printed by the helical shape of the grooves and solids.
Gyroscopic: Conical, pendular movement that derives from the center of gravity
with the rotation movement.
EFFECTS BALLISTICS
The ballistics of effects: "It is the one that studies the results produced in the body or
object that the bullet or projectile impacts, the way the projectile acts on
hitting the target, how the projectile behaves, how the transfer is carried out
kinetic energy and what effects it has on the target, how they work
special projectiles, etc.

Study the damage caused by the projectile and the effects on it, when
it impacts a specific target until it stops.

IDENTIFYING BALLISTICS
It is the part of forensic ballistics that deals with establishing a relationship of
identity between the brands and lesions appearing in the non-combustible elements
of the cartridge (bullet, casing, and primer) and the part of the weapon that has caused
these injuries are mainly fields and stripes of the barrel and closure block,
striker and ejector in your case, which allows for comparisons between
elements fired not struck by a firearm, to relate them to each other.

OPERATIONAL BALLISTICS
It is the set of criminalistics procedures carried out by expert personnel.
in forensic ballistics, carried out in the central laboratory. Scene of the event,
shooting gallery, etc, with all those pieces of evidence collected, sent, obtained or
other compatible ones that can be used and that have ballistic interest, and that do not
they are framed within internal, external, or effects ballistics
identifying, facilitating and complementing in this way the realization of the
exams, inspections, and studies that need to be carried out for a
determination in your assessment, such as the identification of technical character and
functional of the weapons and their ammunition, the restoration of their serial number, the
experimental firing tests and all those procedures necessary for
your adequate work.