Firearms and Ballistics

• Author: Liam Hendrikse
• Pages: 234-268

234

A. OVERVIEW

The forensic discipline of f‌irearms and ballistics is broad and complex, but

the core methodologies employed by experts in the f‌ield are not tremen-

dously dif‌ferent today than when f‌irst developed.1 The basis of any for-

ensic investigation is the ability to ask the right questions. Depending on

counsel’s specif‌ic line of enquiry, the knowledge base needed to ef‌fectively

address forensic f‌irearms issues can range from very basic to highly tech-

nical. Having a good understanding of the fundamentals of how dif‌ferent

types of f‌irearms work, what the components of ammunition consist of,

and the proper use of nomenclature when discussing these issues can en-

sure that the “right questions” are conveyed properly to an expert and

discussed appropriately in a court of law.

Firearms, ballistics, and the role of the f‌irearms expert can be divid-

ed into three general categories: theory, casework, and testimony. Each

of these can be further divided into three distinct areas that can be pre-

sented as evidence for counsel to consider. These are scene of crime work,

1 This is partly due to the fact that the design and use of f‌irearms has not changed

substantially since the Victorian era and the American Frontier. The development

of “modern” f‌irearms and ammunition began to take place in the middle of the 19th

century. The Smith & Wesson Model 1 .22-inch calibre revolver, with its employment

of a fully self-contained metallic cartridge, marked a pivotal point in the develop-

ment of handguns. Such ammunition is still in use today and the semi-automatic

pistol has not changed substantially in design over the last 100 years.

CHAPTER 9

Firearms and Ballistics

Liam Hendrikse

LEgAL ConTExT: CAiTLin PAkosH

Firearms and Ballistics 6 235

analysis at a post-mortem examination, and laboratory analyses and tests.

A complete forensic f‌irearms investigation into a homicide, suicide, or

suspicious death can involve all three areas.

Counsel should have a good understanding of the principles of f‌ire-

arms, what they are capable of doing, what types of evidence they can

produce, and how a f‌irearms expert processes evidence. This understand-

ing is useful when trying to assess whether or not specif‌ic questions—or

forensic “propositions”—have merit (an expert can, of course, assist in

this regard). These propositions can be established in dif‌ferent ways by

counsel or by the expert involved in the case. For example, what types

of specif‌ic situations—or propositions—could produce the physical evi-

dence presented? Conversely, given a hypothetical situation or propos-

ition, what type of physical evidence might one expect as a result?2

When these propositions are investigated by both the Crown and the

defence, a dif‌ferent, and potentially more balanced, picture of the incident

at issue takes form. Defence counsel has the opportunity to see the initial re-

port(s) and explore numerous alternative propositions based on further in-

formation given to them by the client(s), by additional witnesses or evidence,

or by a qualif‌ied expert. The use of a f‌irearms expert can also reveal addi-

tional evidence that counsel may not have been aware of in the f‌irst instance.

B. THE SCIENCE OF BALLISTICS AND FIREARMS IDENTIFICATION

1) Basic Principles

Two essential questions asked on a regular basis by counsel are “what type

of gun is this?” and “how does this gun work?” Understanding how f‌ire-

arms work on a general level can help in understanding the physical evi-

dence encountered in f‌irearms-related casework.

The type of weapon used in a crime will often be dictated by the type of

crime itself. The dramatic increase in drug-related crime has led to a cor-

responding increase in the use of handguns, which are easy to conceal and

are often traf‌f‌icked along with drugs. The use of “long arms” in the form

of rif‌les or shotguns can be found predominantly in domestic or hunting

incidents, in addition to some accidental deaths, suicides and mass shoot-

ings. Military incidents also involve the use of rif‌les, assault rif‌les, and

weapons such as machine guns and sub-machine guns. Nevertheless, the

2 R. Cook et al., “A Model for Case Assessment and Interpretation” (1998) 38:3 Science

& Justice 151.

236 6 Liam Hendrikse

general function and purpose of each type of conventional f‌irearm remains

the same—to use the energy from propellant contained within a round of

ammunition to discharge one or more projectiles with lethal ef‌fect.

Confusion in the courtroom occurs when dif‌ferent people use dif‌fer-

ent terminology to refer to the same object. For example, the term “casing”

has been used in courts to describe a bullet, a cartridge case, and a live

round of ammunition. It is therefore easy to appreciate how quickly con-

fusion can arise in court when presenting or discussing f‌irearms-related

evidence. There is basic nomenclature that should be used. Some of the

most common terms can be found in the glossary to this book.

a) Ammunition

 9.1. Ammunition and its component parts.

In Figure 9.1, items 1 and 4 show rounds of live, or unf‌ired, ammunition

(sometimes referred to as cartridges) of dif‌ferent calibre and style. Items

2, 3, 5, and 6 show the component parts of the cartridge, with 2 and 5 being

the actual bullets and 3 and 6 being the cartridge cases/casings). The bullet

is typically one of two types: a “metal jacketed bullet,” which has a thin

layer of metal over what is typically a lead core f‌itted to a brass or metal

cartridge case (shown in items 1–4); or a solid lead bullet (shown by item

5), which is more commonly found in ammunition for revolvers. The car-