Thursday, May 31
Morning Technical Session
speed cameras have become faster and faster in
recent years. Two Shimadzu HPV 1 digital high
speed cameras capable of 1,000.000 frames per
second were available to the Kurzzeit company of
Werner Mehl. This brought up the idea to produce
stereoscopic 3D high speed videos of shotgun
pellets and other projectiles in flight and upon
impact on different material. Also the explosion
of a revolver was captured in 3-D.
The digital high speed videos were produced with
two simultaneously triggered Shimadzu high speed
cameras. The illumination was achieved with
special flashes. The complete triggering of the
whole setup was done with a RTTS trigger system
and a Kurzzeit chronograph. Both videos where
merged with special software to produce anaglyph
images to provide a stereoscopic 3D effect. This
effect is commonly known from 3D movie theaters.
For viewing the videos the typical 2 color
glasses are necessary.
The goal to produce 3-D high speed videos of
ballistic incidents was achieved. The critical
task is to (at the right moment) trigger and
synchronize both cameras and the flashes within
up to 1/1.000.000 of a second. This was possible
with the equipment.
The stereoscopic effect enables the viewer to
get a 3 dimensional impression of the particle
movement and the dispersion of fragments. The
understanding of the high speed dynamics
involved is improved.
The AFTE Glossary states that: The theory of
identification as it pertains to the comparison
of toolmarks enables opinions of common origin
to be made when the unique surface contours of
two toolmarks are in sufficient agreement.
This study was designed and conducted in a way
to test the long held theory that fired
cartridge cases originating from different
firearms vary sufficiently in individual
characteristics to the point where incorrect
identifications and incorrect eliminations occur
at a very low rate. This study was designed as a
validity test to be completed by fully trained
firearms examiners on a wide scale, throughout
the discipline, to obtain a large enough sample
population to provide substantial results.
Twenty double blind sample sets were created to
be sent to fully trained examiners across the
United States. These sample sets consisted of a
series of questions and knowns that originated
from a pool of firearms. Isolated concentration
on breech face marks was desired; to facilitate
this, many parts that typically create
identifying marks were kept constant. Great care
was taken to anonymously send the sample sets to
firearm examiners across the nation along with
an equally anonymous method of reporting the
conclusions. Each examiner was asked to record
his/her results for the examination of each
unknown in the sample set to include typical
results of identification, elimination and
inconclusive results when compared to the knowns;
as well as inter-comparisons within the pool of
unknowns when necessary.
To be determined before AFTE 2007.
To be determined before AFTE 2007.
What happens when
politics, the law, and forensic science mix?
This is a relatively common occurrence, but when
it involves firearms, the task of identifying
specific types based on manufacturer, model, or
even physical characteristics, the resulting
outcome may be daunting for even the most
This anecdotal paper will go into detail on the
18 year history of Assault Weapons Laws in the
State of California, what it has attempted to
regulate, issues it has raised, examples
involving various types of firearms and devices,
the impact it has on the Firearm Examiner, and
what you may need to consider if your
jurisdiction is planning to enact such
Give a general introduction to a more classroom
orientated training approach for microscopic
Stage Discussions with trainees about
identifications through the use of Drugfire
Introductory Stage Grouping the images
together to form individual topics for
classroom presentations. Examples of early
classroom presentation include ad hoc power
point presentation for manufacturing marks
and variations in firing marks for trainees.
Other materials include presentations of
unusual case studies for technical meeting
for working staff.
& Developing Stage Put together the
training materials available for the
trainees and started the classroom training
program with practical exercises.
Development cycles started when trainee
asked specific questions that needed to
address and good examples from their
of the system The trainees confidence
could only be built up through both
practical exercises. The confidence of the
trainer in the trainees built up through
reviewing the ability of the trainees to
solve their practical exercises.
Summary of Results
In order to ensure the competency of the
trainee, we used the competency test normally
used for testing the competency of newly
employed experienced firearms examiner. Four out
of the five students passed the competency test.
We learned from the experience and modified the
exercise requirements to avoid reoccurrences.
The classroom approach yielded good result so
far and the students could acquire more visual
exposure to microscopic comparisons. It is more
cost effective as most of the time only one full
time trainer is required for the training
program. When the full training materials are
developed, it would be a comprehensive and
systematic training program.
This is an
informational update on the Scientific Working
Group for Firearms and Toolmarks. The
presentation include a brief history of the
working group, current Board Members,
objectives, committees, and the
documents/guidelines approved and available for
Upon completion of the Overview, a more detailed
look will be taken at one of the most recent
The Scientific Working Group for Firearms &
Toolmarks (SWGGUN) has produced an Admissibility
Resource Kit that is designed to assist Firearm
& Toolmark Examiners for admissibility hearings
related to the science of Firearm & Toolmark
This overview will familiarize examiners with
the content of the kit which includes:
Overview of the Admissibility Rules
Foundational Overview of Firearm & Toolmark
A Review of
the Admissibility Elements
Supporting and Opposing Viewpoints to
Firearm & Toolmark Identification
Appendices that include a Glossary of Terms,
Online Resources and Visual Aids
Power Point Presentation based on the material
within the resource kit was developed. This
presentation can be adapted to an examiners
specific needs and will be available for
download under the Visual Aids section of the
resource kit. This Power Point Presentation will
A case example of how to approach a long
distance shooting is presented. Care has to be
taken to exclude any other possibility: direct
shots and bullets falling from the sky.
To corroborate the long distance shooting, a
number of clues and tools are given that will
help to decide.
The results of a partial bullet trajectory
reconstruction at the scene are used to simulate
the complete bullet path with existing software
EBV4 and Sierra's Infinity-5.
It is explained how this software can be applied
to approach this problem and what useful
information can be derived from this.
The bullet is examined with a microscope to look
for any possible damage indicating a base first
or tumbling bullet strike.
Corroborative test firings were executed,
whenever necessary with downloaded ammunition,
to examine the bullet's penetration/perforation
capabilities. The bullet's velocity was tracked
with a Weibel Doppler radar.
The bullet trajectory and degree of wounding
were grounds to reject a direct shooting.
Bullet damage examination learned that it struck
nose first, which is usually not expected for a
bullet falling from the sky.
The trajectory reconstruction gave values for
the angle of departure and downrange velocity.
It was checked with test firings that the
downrange velocity was still sufficient to
explain the observed damage and wounding.
Conclusions: In presumed long distance shootings
all possibilities should be checked to exclude
direct shots and bullets falling from the sky:
- What is
the damage to the bullet and what is the
damage to any intermediary objects and/or
persons that were hit?
- What are
the required velocities for penetration /
perforation of the given bullet / target
- Does the
velocity drop while perforating a target
changes at a lower downrange velocity?
that was used for the trajectory reconstruction
gave a good indication for angle of departure
and range. Between the 2 programs there is a
minor difference in downrange velocities. The
ballistic coefficient should be chosen with care
as it has an important influence on the
determine the resolution capabilities of current
microscope technology as compared to earlier
produced comparison macroscope systems.
Correlation to the theoretical limits as defined
by calculated values are compared to observable
Method: Seventeen trained operators used
a certified resolution test slide with
reproducible illumination and magnifications, to
determine the resolving capabilities on 16
different comparison macroscopes systems ranging
in age from less than 12 months to more than 30
Summary of Results: New Microscopes out
performed older systems consistently, however,
it does not prove that older microscopes are not
capable of resolving structures that are typical
of firearms and toolmark examinations:
General Conclusions: A variety of factors
lead to the ability of a microscope system to
resolve structures, including illumination,
filtering, gender, age of the instrument,
instrument maintenance, color of light, and
visual acuity of the operator.
Objectives: (1) To determine the cartridge
interchangeability between the 17 and 22 caliber
families. (2) To study the effect of this
interchangeability on physical and individual
characteristics exhibited on fired bullets.
Methodology: Utilizing a Ruger Single Six
revolver, test fires were obtained from
combinations of 17 and 22 caliber
cylinders/barrels. Various bullet materials were
used in the test firing process. Microscopic
examination was performed on the test fired
bullets to determine if physical and/or
individual characteristics were exhibited.
Results: The different 17 and 22 caliber
cylinder/barrel combinations showed definite
physical characteristics including increased
length, decreased diameter, and unusual
deformation in some cases.
Conclusions: (1) It is possible to fire 22
caliber bullets from a 17 caliber chambered
cylinder and barrel with no modification to the
- 22 Short
caliber cartridges can be loaded and fired
in a cylinder chambered in 17
- 22 Long
Rifle caliber cartridges can be loaded and
fired in a cylinder chambered for 17 HMR.
(2) The unique
physical characteristics exhibited by the test
fired bullets obtained from the cylinder /
barrel combinations have the potential to aid
examiners in the event that similar items are
received in case work.
machining of microscopic encoding structures on
specific firearm components has been proposed to
assist in the identification of expended
ammunition components found at crime scenes.
Since the release of the first generation of
this technology significant advances in the
laser machining technology and in the encoding
structures have been made. This study involved
the testing of second generation firing pins
produced by ID Dynamics, LLC. Second generation
micro-marked firing pins contain three different
forms of encoding: alphanumeric, gear and radial
bar codes. The durability of these micro
characters and legibility of their impressions
were observed by the testing of eleven
semi-automatic pistols, two semi-automatic
rifles and a pump action shotgun on a variety of
different ammunition brands. All cartridge cases
were analyzed using a stereo zoom microscope
equipped with a ring light and polarizing
filter, and all firing pins were analyzed
utilizing a Philips XL30 Scanning Electron
The alphanumeric and gear code structures showed
minimal signs of degradation with repeated test
firing beyond 1000 rounds; however specific
instances of degradation were noted. Eight of
the eleven semi-automatic pistols tested showed
severe degradation of the radial bar code
structures. This degradation was caused by the
continual contact between the sides of the
firing pins and the firing pin aperture. This
contact obliterated a section of the radial bar
code structures. The applicability of the codes
other than the alphanumeric could not be
evaluated because decoding information was not
available. This study suggests that the
placement of an eight digit alphanumeric code on
the face of the firing pin is the most durable.
Any increase in the number of digits in this
code would reduce the legibility of the
The legibility of the impressions produced by
these micro-marked firing pins varied between
firearms. Transfer rates were observed from zero
to 100% for all encoding formats. All of the
semi-automatic pistols and one semi-automatic
rifle showed a minimal decrease in the
legibility of the impressed characters with
continued test firing. Three major factors
affected the legibility of the impressed
characters for each of the firearms tested:
ammunition brand, firing pin drag, and multiple
strikes of the firing pin within the same
impression (all firearms tested did not produce
firing pin drag and multiple firing pin
strikes). The legibility of the impressed
characters was directly dependent upon the brand
of ammunition tested. This ammunition brand
dependence was confirmed upon repeated test
firing of each brand of ammunition. One
semi-automatic rifle and the pump action shotgun
showed a decreasing trend in impression
legibility throughout test firing. This decrease
in transfer rate was correlated with the
degradation of the encoding structures on these
two firing pins. This technology is currently
not suitable for .22 caliber rimfire firearms.
At the present time this technology is feasible,
but is not applicable to all firearms. Further
research and development needs to be completed
prior to the widespread commercial
implementation of this technology.
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Copyright © 2006 Association of Firearm and Tool Mark Examiners
All rights reserved. Revised:
June 05, 2007.