Ballística

Which are the Ballistic Divisions/Branches?

The etimology of Ballistic Science originated from the Greek word “Ballein” which

means “to throw” and from the Roman word “Ballista” which is machine to hurl a

stone. From those words the modern term for Forensic Ballistics was derived to indicate

the science of moving projectile.

In the subject of Ballistics, the whole amplitude of techniques is summarized in four

main branches, which are.

Interior Ballistics: Traits of the motion of the projectiles while still in the firearm,

namely the studies of combustion of the powder, pressure developed and velocity.

Exterior Ballistics: Traits of the motion of the projectiles after leaving the muzzle

namely trajectory, velocity, range penetration, etc.

Terminal Ballistics: Traits of the effects of the projectile on impact on the target.

Forensic Ballistics: The science of firearms identification by means of the ammunition

fired through them. This one is also divided in two subdivisions, that are the following.

 Field Investigation: refers to the work of an investigation in the field. It concerns

mostly with the collection, marking, preservation, packing and transmission of

firearms evidences. It include the study of class characteristics of firearms and

bullets.

 Technical Examination: refers to the examiners who examine bullets/ or shells,

whether fired from also whether or not cartridges were loaded and ejected made

by the suspected firearms submitted. Reports are made by the examiners and

testify in court regarding their reports.

In synthesis, Ballistic Sciences study the complex world of guns and bullets. But

technically, what’s the meaning of a Firearm? There are two possible answers to this

question.

 Legal Definition of Firearm: “Firearms” or “Arms” are herein used includes

rifles, muskets, carbines, shotguns, revolvers, pistols and all other deadly

weapons from which a bullet, ball, shot, shell or other missile may discharge off

by means of gunpowder or other explosives. The term also includes air rifles

except such as being of small caliber and limited range used as toys. The barrel

of any firearm shall be considered a complete firearm for all purposes hereof

(Sec. 877, Revised Administrative Code see also Sec. 290 National Internal

Revenue Code).

 Technical Definition of Firearm: instrument used for the propulsion of a

projectile by means of expansive force of gases from burning powder.

 Ammunition: under the National Internal Revenue Code the word

“Ammunition” shall mean loaded shell for rifles, muskets, carbines, shotguns,

revolvers and pistols from which bullets, ball shot, shell or other missile may be

ammunition for air rifles.


What signs do we have to look for in a fire weapon death?

The signs that will mark a death by firearm are by:

Classification of Firearms

Short weapons

• Stir

 Gun

• Machine gun

Long weapons

• Rifle

• Shotgun

• Rifle

Depending on the load projected on each shot:

 • Single projectile or bullet weapons

• Multiple projectile weapons: shrapnel, posts, pellets...

According to the construction of the weapon:

1. Typical weapons: they are the ones constructed as such by the different

manufacturers for the different uses

2. Atypical weapons: they are the ones modified or manufactured of homemade form:

pipes, of imitation modified, of collector, etc.

Morphology of Wounds By Firearms

Injury of entry

• Hole

It can be unique (most common) or multiple.

Can be rounded or oval.

You can follow the lines of elastic fibers.

In shots at close range and more in the mouth of pitcher, star shape, by the effect of

gases (from inside to outside).

Variable diameter. Greater or smaller than the projectile. It influences the shape of the

projectile, the speed of arrival and the elasticity of the skin.

• Tattooing

They are the elements that are placed around the hole.

It consists of the concussion band and the inlay or tattoo proper.

CONTINUOUS BODY

It is placed immediately after the hole and is produced by:

1. Contusion of the skin by the bullet.

2. Breaks of elastic fibers by distension of the skin, before breaking.

3. Rubbing of the skin by the rotation of the projectile.

4. Cleaning of the dirt carried by the bullet through the skin.

TARACEO

It is formed by:

Flame burning

• The carbon black tank.

• The incrustation of the powder.

There is a deleble (washable) and indelible (not washable) inlay. The latter consists of

the burn and the powder grains that have been embedded more deeply.

Journey

It is the route of the projectile inside the body.

They can be rectilinear or diverted.

Deviations may be due to collisions with bones which, if fragmented, give rise to

multiple paths.

Output hole

May or may not exist.

Very variable in shape and size.

By the mechanism of production usually has everted edges.

If there has been fragmentation, there may be more than one.

Bruise and bruise ribbon lack.

There are also other kind of identifications to be considered, such as the following,

which represent the standard of an investigation.

Principles of Identification (Bullets)

 No two barrels are microscopically identical as the surface of their bores all

possesses individual characteristics markings of their own.

 When a bullet is fired from rifled barrel, it becomes engraved by the rifling and

this engraving will vary in its minute details with every individual bore. So it

happens that the engraving on the bullets fired from one barrel will be different

from another bullet fired from another barrel.

 Every barrel leaves its thumb mark or fingerprint on very single bullet fired

through it just as every breech face leaves its thumb mark on the base of every

fired cartridges case.

Principles of Identification (Shells)

 The breech face and striker of every single firearm leave microscopical

individualities of their own.

 The firearm leaves its “fingerprints” or “thumb mark” on ever cartridges case

which it fires.

 The whole principles of identification is based on the fact that since the breech

face of every weapon must be individually distinct, the cartridges cases which it

fires are imprinted with this individuality. The imprints on all cartridges cases

fired from the same weapon are always the same; those on cartridges cases fired

from different weapons are different.


What is a Trespassing Breach?

The so called trespassing breach is the one made by a high or medium caliber weapon,

generally made by automatic rifles or snipers (that have ammunition larger than an inch

and thickness larger than 9mm in the bullet), and has a size as big as it has the capability

to break through the point were the weapon was shot, making a hole from entrance to

exit in the body that receives the shot. Additionally, a bullet shot by this weapons goes

even faster than the speed of sound, causing it to carve from an edge to another. Are the

ones that have an entrance and an exit.


What is a Bouncing Breach?

A bouncing breach is the one made by small weapons, and even blind bullets in

some cases, that reach the point of making damage to the body or the surface they

are aimed, but the intensity (meaning forces acting in the bullet) are not as strong

to penétrate completely the object, so they make holes in it, but then the bullet

“bounces” off it, and doesn’t inlay deeper. That is why the phenomena is called

bouncing breach, and it’s often used in bulletproof vest technology, and police

practices. The one that just scratches the surface.


What is a Blind Breach?

The blind breach is defined as the one that has a powerful enough bullet to

penetrate the surface of an object, but the pojectile gets stucked in the body or

structure, so it doesn’t get out. It can be shortly defined by the premise: The breach

that has an entrance but not an exit. These effects are mainly caused by handguns

or weapons with low caliber.


What do we establish in Reconstructive Ballistics?

The shooting reconstruction methods are different: use of strings, by digital

reconstruction, with the usage of lasers, etc. This process is used to determine factors as

where were the shooters when the incident occurred, how many shots were fired, what

could the shooters see, and what environmental factors surrounded the scene. Those

facts show the jury what exactly happened during the shooting.


Define: Penetration Angle, Inclination Angle and Incidence Angle

Penetration Angle: Is defined as the angled formed between the horizontal that passes,

and the bullet’s trajectory, considering that the body is in an anatomic position or laid in

a bed.

Inclination Angle: It’s the angñe that indicates the inclination of the deceased at the

moment of impact. It can be measured with many instruments.

Incidence Angle: The angle formed by the horizontal in the Entering Hole, taking in

consideration the angle of penetration of the bullet and the angle of the victim’s position

involved.



Peckley, M (2016). Forensic Ballistic. Washington, DC: Criminology Matters. Pages 1-

12. Recovered From the National Criminal Science and Technology Association.

From: http://mfpeckley.yolasite.com/pages-and- files.php

Schaefer, J (2005). Terminal Ballistics. London: Fr. Frog. Page 1. Recovered from:

http://www.frfrogspad.com/terminal.htm

University of Utah (2015). Ballistics. Utah: Faculty of Medicine. Page 1. Recovered

from: http://library.med.utah.edu/WebPath/TUTORIAL/GUNS/GUNBLST.html