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Firearms & Tool Marks Section Quality Manual
Document ID: FA-DOC-01 Approved By: Executive
Director/Scientific Operations Director Revision Date: May 6, 2010
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A R K A N S A S STATE CRIME LABORATORY
FIREARMS & TOOLMARK
QUALITY MANUAL
Executive Director:
Kermit B. Channell, II
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Firearms & Tool Marks Section Quality Manual
Section 1.0
Introduction...................................................................................................................
5
1.1 Organizational and management
structure............................................................................
5 Section 2.0 Personnel Qualifications and
Training..........................................................................
6
2.1 Job Description- See Employee History Binder
...................................................................
6 2.2 Educational Requirements
....................................................................................................
6
2.2.1 Chief Firearms
Examiner..............................................................................................
6 2.2.2 Firearms
Examiner........................................................................................................
6 2.2.3 Firearms Examiner
Trainee...........................................................................................
6
2.3 Special Training
Requirements.............................................................................................
6 Section 3.0
Facilities........................................................................................................................
7
3.1 Security
.................................................................................................................................
7 Section 4.0 Evidence
Handling........................................................................................................
8
4.1
Scope:....................................................................................................................................
8 4.2 Classification:
.......................................................................................................................
8 4.3
Basis:.....................................................................................................................................
8 4.4 Procedures For Evidence Handling:
.....................................................................................
8
4.4.1 Evidence handling upon initial examination:
............................................................... 8
Section 5.0
Validation....................................................................................................................
10 Section 6.0 Analytical Procedures
.................................................................................................
11
6.1 Firearms Identification
Protocols........................................................................................
11 6.1.1 Physical Examination and Classification of Firearms
................................................ 11 6.1.2 Safe
Firearm
Handling................................................................................................
12 6.1.3 Pre-Firing Safety Examination
...................................................................................
12 6.1.4 Trigger Pull
Examination............................................................................................
13 6.1.5 Barrel and Overall Length Measurement of a
Firearm............................................... 16 6.1.6
Rusty Firearm Examination
........................................................................................
17 6.1.7 Sound Suppressor Examination
..................................................................................
17 6.1.8 Malfunctioning Firearm
Examination.........................................................................
18 6.1.9 Firearms Reference Library
........................................................................................
21 6.1.10 Test Firing and Recovery of Test
Fires.......................................................................
23 6.1.11
Downloading...............................................................................................................
25 6.1.12 Primed Cartridge Case/Shotshell
................................................................................
26 6.1.13 Caliber
Determination.................................................................................................
27 6.1.14 Measuring Land Impression and Groove Impression Widths
.................................... 28 6.1.15 National Integrated
Ballistic Information Network
.................................................... 30 6.1.16 GRC
Utilization
..........................................................................................................
32 6.1.17 Wadding
Determination..............................................................................................
33 6.1.18 Shot Determination
.....................................................................................................
34 6.1.19 Physical Examination & Classification of Fired
Bullet/Slug Evidence...................... 35 6.1.20 Physical
Examination & Classification of Fired Cartridge Cases
.............................. 37 6.1.21 Physical Examination &
Classification of Fired Shotshells
....................................... 38 6.1.22 Subclass
Characteristics..............................................................................................
39 6.1.23 Microscopic Comparison
............................................................................................
40 6.1.24 Trace Material Examination
.......................................................................................
41
6.2 Range Determination
Protocol............................................................................................
43
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6.2.1 Visual
Examination.....................................................................................................
43 6.2.2 Microscopic Examination
...........................................................................................
44 6.2.3 Infrared (IR) Photographic Examination
....................................................................
46 6.2.4 Haemo-Sol Cleaning of
Bloodstains...........................................................................
48 6.2.5 Diphenylamine Test
....................................................................................................
49 6.2.6 Modified Griess
Test...................................................................................................
50 6.2.7 Sodium Rhodizonate Test
...........................................................................................
52 6.2.8 Dithiooxamide (DTO)
Test.........................................................................................
54 6.2.9 Distance Determination Test Pattern
Production........................................................
56 6.2.10 Gunshot Residue (GSR) Pattern Without a
Gun......................................................... 57
6.3 Tool Mark Identification Protocol
......................................................................................
59 6.3.1 Examination and Physical Classification – Tool
........................................................ 59 6.3.2
Examination and Physical Classification – Tool
Mark............................................... 60 6.3.3
Subclass
Characteristics..............................................................................................
60 6.3.4 Trace Material Examination
.......................................................................................
61 6.3.5 Test
Standards.............................................................................................................
62 6.3.6 Microscopic Comparison
............................................................................................
63 6.3.7 Magnesium Smoking
..................................................................................................
64 6.3.8 Casting
........................................................................................................................
65
6.4 Serial Number Restoration Protocol
...................................................................................
66 6.4.1 Serial Number
Restoration..........................................................................................
66
6.5 Fracture Match Protocol
.....................................................................................................
70 6.5.1 Fracture Match
............................................................................................................
70
6.6 Range of Conclusions
.........................................................................................................
73 6.6.1 Firearms Range of Conclusions
..................................................................................
73 6.6.2 Toolmarks Range of
Conclusions...............................................................................
73
6.7 Work Sheets
........................................................................................................................
75 6.7.1 Firearm Work Sheets:
.................................................................................................
75 6.7.2 Fired Bullet Work Sheet:
............................................................................................
75 6.7.3 Discharged (Expended) Cartridge Case Work
Sheet:................................................. 76 6.7.4
Firearms Worksheets
..................................................................................................
76
Section 7.0 Calibration and Maintenance:
.....................................................................................
78 7.1 Calibration
Standards..........................................................................................................
78
7.1.1 Comparison Microscope:
............................................................................................
78 7.1.2 Stereo Microscope:
.....................................................................................................
78 7.1.3 Measuring Projection Microscope:
.............................................................................
79 7.1.4 Stage
Micrometer........................................................................................................
79 7.1.5
Balances/Scales...........................................................................................................
79 7.1.6 IBIS /
NIBIN...............................................................................................................
79 7.1.7 Trigger Pull Devices
...................................................................................................
79 7.1.8 Digital Caliper/ Dial
Caliper.......................................................................................
80 7.1.9 Rectangular Gage Blocks (0.050 inches, 0.200 inches, 0.400
inches and 1.000 inches) 80
Section 8.0 Proficiency Testing:
....................................................................................................
82 Section 9.0 Case
Records...............................................................................................................
83
9.1 Examination Documentation
..............................................................................................
83
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9.2 Technical and Administrative
Review................................................................................
83 Section 10.0 Testimony Review
..................................................................................................
84 Section 11.0
Audits......................................................................................................................
85 Section 12.0 Complaints
..............................................................................................................
86 Section 13.0 Miscellaneous
.........................................................................................................
87 Section 14.0
APPENDIX.............................................................................................................
88
14.1 Glossary
..............................................................................................................................
88 14.2
Abbreviations......................................................................................................................
88
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Firearms & Tool Marks Section Quality Manual
Section 1.0 Introduction The purpose of this Quality Manual is
to establish general guidelines for the handling of firearms, tool
mark evidence, serial number evidence; the examination of firearms
evidence, tool mark and serial number evidence; the reporting of
firearms, tool mark and serial number results; and the response to
court commitments.
Goal
It is the goal of firearm examiners to insure the quality,
integrity, and accuracy of the examination and analysis of firearm
and tool mark evidence through the implementation of a Quality
Assurance Program and to:
1. Provide such services to law enforcement agencies, attorneys,
and courts in criminal matters in accordance with the policies of
the laboratory.
2. Provide expert witnesses for criminal judicial proceedings in
accordance with the policies of the laboratory.
Objective It is the objective of the Quality Assurance Program
to:
1. Monitor, on a routine basis, the examinations and analyses of
the firearms examiners by means of quality control standards and
proficiency tests.
2. Verify that all section protocols and procedures are within
established performance criteria, that the quality and validity of
the analytical data are maintained and that the raw data gathered
provides a sound foundation for reliable conclusions.
3. Ensure that problems are noted and that corrective action is
taken and documented.
1.1 Organizational and management structure Refer to FA-DOC-03
for Firearms Section Organization & Management Structure
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Section 2.0 Personnel Qualifications and Training
2.1 Job Description- See Employee History Binder
2.2 Educational Requirements
2.2.1 Chief Firearms Examiner The position requires a minimum of
a four year degree from an accredited college or university with a
major in forensic science, criminalistics, or in a physical or
natural science and five years of professional experience as a
Firearms Examiner in a forensic laboratory.
2.2.2 Firearms Examiner A four year degree from an accredited
college or university with a major in forensic science,
Criminalistics, or in a physical or natural science and one year of
professional experience as a Firearms Examiner in a forensic
laboratory or identification division. In addition, completion of
the Association of Firearms and Toolmark (AFTE) Training Program,
The Arkansas State Crime Laboratory Firearms Examiner Training
Program or a comparable program from another forensic laboratory or
institution is required.
2.2.3 Firearms Examiner Trainee Individuals with a four year
degree from an accredited college or university with a major in
forensic science, Criminalistics or in a physical or natural
science and a broad knowledge and background in firearms is
recommended.
2.3 Special Training Requirements Professional experience as a
Firearms examiner in a recognized forensic laboratory, institution,
or an identification division may be substituted on a one year work
time for one year of the required educational background. The
individual must have testified as an expert in the field of
Firearms identification in a court of law.
An individual selected as a Firearms analyst trainee must be
able to successfully complete the AFTE Training Program, the
Arkansas State Crime Laboratory Firearms Training Program or a
comparable program from another forensic laboratory or institution
is required.
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Section 3.0 Facilities The Firearms section consists of six
office areas, two microscope examinations room, GSR/Serial number
restoration room, tool room, bullet recovery room, indoor firing
room, firearms reference library and a NIBIN firearm processing
room.
3.1 Security Access to all of the office areas, microscope
examination room, tool room, bullet recovery room, indoor firing
range and a NIBIN firearm processing rooms require a key for access
twenty four hours a day.
The firearm reference library is accessed by entry through
evidence receiving where a log is maintained regarding entry and
exit.
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Section 4.0 Evidence Handling
4.1 Scope: Evidence must be preserved to prevent significant
change or alteration during the examination through the completion
of analysis. Evidence must be kept secure and the chain of custody
must be maintained once an examiner from the Firearms Section has
assumed custody of that evidence.
4.2 Classification: Items submitted or received through the use
of a laboratory submission form will be treated as evidence.
Ammunition components which have been test fired through firearms
for the purpose of examination or entry into the NIBIN computer
database will be identified and treated as reference material
requiring the identification of the appropriate laboratory case
number on the outside package or inside information card.
4.3 Basis: In order to maintain the security, chain of custody
and to prevent change, all evidence must be stored under proper
seal, in the proper packaging and in a secure area.
4.4 Procedures For Evidence Handling: Evidence will be checked
out from Evidence Receiving in accordance with evidence
policies.
4.4.1 Evidence handling upon initial examination: • Be aware of
all the sections and testing that involves the evidence. Take the
necessary
precautions to preserve the integrity of the evidence.
• Descriptions of evidence containers, sealing, initials (this
includes both outer and inner packaging) and evidence that is to be
examined will be recorded in the case notes. Any discrepancies
should be noted.
• When evidence containers are opened for examination, opening
through the seals of other individuals who handled the evidence
should be avoided, if at all possible.
• When evidence containers are opened for examination, the
contents should be inventoried. This inventory should be matched to
the Crime Laboratory Submission Sheet.
• Discrepancies shall be noted in the examiner’s notes. If
deemed necessary, the submitting officer or agency will be
notified. All case-related communication will be documented on an
ASCL-FORM-06 Agency Contact Form.
• Evidence in progress may be stored in lockable cabinets, the
tool room, the GSR/Serial number restoration room, and the
ammunition storage room. Evidence must be kept in one of these
locations for overnight storage.
• Each piece of evidence or its most appropriate proximal
container must bear the following identifiers:
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1. Laboratory number (e.g. YYYY-000000)
2. Laboratory (section) Item number
3. Examiner’s initials
• If reusing the original container is impractical, a new
evidence container may be used. It shall also be marked and sealed
according to laboratory procedures and the original evidence
packaging shall be maintained, either inside the second evidence
container or complete documentation along with a picture of
original packaging. Documentation of the change in packaging along
with description must be entered into the case file for future
reference.
• The evidence will be returned to Evidence Receiving in a
timely manner after completion.
• All pertinent information about the evidence will be recorded
in the examiner’s notes. Case documentation must be sufficient to
allow a technical peer review to be conducted.
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Section 5.0 Validation • Refer to ASCL Lab Wide Quality
Manual
Document ID: FA-DOC-01 Approved By: Executive
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Firearms & Tool Marks Section Quality Manual
Section 6.0 Analytical Procedures Introduction This section
provides standard procedures for tests and examinations performed
by the forensic firearms and tool marks examiner. These procedures
may involve hazardous materials, operations and equipment. These
procedures do not purport to address all of the safety problems
associated with its use. It is the responsibility of the user of
these procedures to establish appropriate safety and health
practices and determine the applicability and normal limitations
prior to use. Proper caution must be exercised and the use of
personal protective equipment must be considered (see ASCL Health
and Safety Manual for safety requirements). Personal protective
equipment includes, but is not limited to: lab coats, latex or
nitrile gloves, safety glasses, and hearing protection devices. The
examiner must consider the practicality and/or desirability to wear
some form of bullet resistant clothing. Proper caution should
include strict adherence to the ASCL Health and Safety Manual.
6.1 Firearms Identification Protocols
6.1.1 Physical Examination and Classification of Firearms •
Other Related Procedures
o Safe Firearm Handling o Pre-Firing Safety Checks o Trigger
Pull Examination o Barrel and Overall Length Measurements
6.1.1.1 PROCEDURE or ANALYSIS • The initial examination of any
firearm will include the completion of a firearm worksheet.
This worksheet will include the manufacture data, if available,
of the firearm and will serve as a source to document the condition
of the firearm as received and any tests performed to or with the
firearm.
• The firearm worksheet may also include determining the
following when appropriate: o Location and type of trace evidence o
Caliber/Gauge o Make/Model o Serial Number o Firing Mechanics o
Type of Action o Safeties o Operating Condition o Trigger Pull
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o Rifling Characteristics o Barrel Length o Overall Length o Any
other data as per Appendix 4.
6.1.2 Safe Firearm Handling Firearms evidence in the laboratory
environment must be handled correctly and treated with respect.
Occasionally, loaded firearms are received in evidence for a
particular examination. These, of course, need very special
handling. All firearms must be treated as though they are loaded.
This rule cannot be over stressed and must be followed at all
times, whether it’s in the evidence receiving area, firearms
section, test firing area or in court. Safe firearm handling within
the laboratory environment corresponds with safe firearm handling
in general. The only way to prevent accidents is to practice safety
at all times.
• OTHER RELATED PROCEDURES o Physical Examination and
Classification of Firearms o Pre-Firing Safety Checks o Trigger
Pull Examination o Barrel and Overall Length Measurements
6.1.2.1 PROCEDURE or ANALYSIS • The muzzle of the firearm must
always be pointed in a safe direction.
• Prior to any examination, regardless of which section is
receiving the firearm, a competent individual must ascertain the
loaded or unloaded condition of the firearm. This process must be
accomplished before the firearm is received by the laboratory.
• Test firing or any examination of the firearm that utilizes
live ammunition, or a live ammunition component, will only be
performed in designated test firing areas.
• A firearm will not be placed in the evidence vault or returned
to any agency in either a loaded condition or prior to its loaded
or unloaded condition being checked.
6.1.2.2 REFERENCES • “A Guide to Firearms Safety”, A Safety and
Educational Publication of the National Rifle
Association, May 1994.
• “Technical Protocols for the Handling of Firearms and
Ammunition”, FBI, June 1992.
6.1.3 Pre-Firing Safety Examination It is the responsibility of
the firearm examiner to ensure that all appropriate safety function
checks are performed on a firearm or item of ammunition prior to
test firing. The following is a list of safety checks, which shall
be considered. The examiner must be mindful that individual case
situations may require a more extensive function test process than
that which is listed here.
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• OTHER RELATED PROCEDURES o Safe Firearm Handling
6.1.3.1 PROCEDURE or ANALYSIS • Deciding whether or not a
firearm can be safely test fired from the normal hand held
position
o Is the chamber/bore clear? o Are there any signs of cracks or
weaknesses in major parts of the firearm; such as the
frame, slide or barrel?
o Does the firearm function, lock-up or dry fire as you would
expect it to? o Is the correct ammunition being utilized?
• Is it appropriate to utilize the evidence ammunition? o Are
there signs of reloading? If so, reconsider the need to test fire
the evidence
ammunition.
o Are there splits in the cartridge case neck and/or other
significant damage to the cartridge case?
o Is the ammunition of the correct caliber? This assessment of
caliber cannot be based on the head stamp!
o Are there existing toolmarks on pertinent surfaces of the
ammunition? o Is the ammunition needed for other tests; i.e., range
determinations?
• Muzzle Loaders. o Does the chamber/barrel appear sound? o Do
the percussion nipples have oversize flash holes? o If a black
powder firearm is received in the loaded condition, it must have
the bullet
and charge removed. It may then be properly loaded prior to test
firing.
o Is this an "original" muzzleloader or a modern reproduction?
"Originals" must always be remote fired.
6.1.3.2 INTERPRETATION OF RESULTS: If any of the above
considerations cannot be answered with a clear "yes" or otherwise
rectified and test firing is necessary, that firearm must be remote
fired.
6.1.4 Trigger Pull Examination Trigger pull is defined as the
amount of force, which must be applied to the trigger of a firearm
to cause sear release. This examination can provide vital
information regarding the mechanical operating condition of the
firearm. The trigger pull of a firearm can be obtained utilizing
standard trigger weights, which make contact with the trigger at a
point where the trigger finger would normally rest.
• OTHER RELATED PROCEDURES
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o Physical Examination & Classification of Firearms o Safe
Firearm Handling
• INSTRUMENTATION o Standard Trigger Weights o Spring Gauge
6.1.4.1 PROCEDURE or ANALYSIS The trigger pull examination
normally is conducted after the firearm has been successfully test
fired. There is a remote possibility that the firearm may be
damaged during this examination.
• SINGLE ACTION TRIGGER PULL WITH STANDARD TRIGGER WEIGHTS o
Insure that the firearm is unloaded. o Cock the firearm. o Hold the
firearm with the muzzle vertical. o Rest the trigger hook of the
standard trigger weight hanger on the trigger where the
average finger would normally rest, making sure it is not
touching any other part of the firearm, with the weights hanging
parallel to the bore of the firearm.
o Add the weights until the sear releases. o Check two or three
times, resetting the sear connection after each attempt. Record
the
heaviest weight at which the sear will hold and not release.
Record the lightest weight necessary to cause consistent sear
release. This will be the trigger pull range. Note any revolver
cylinder chamber that alters the trigger pull
o It should be noted that measuring the trigger pull of a
rimfire firearm should not be performed on an empty chamber. A
“dummy” cartridge should be used. The examiner must also take into
consideration the potential for damage of a centerfire firearm and
may wish to use a “dummy” cartridge in this instance as well.
• DOUBLE ACTION TRIGGER PULL WITH STANDARD TRIGGER WEIGHTS o
Insure that the firearm is unloaded. o Hold the firearm with the
muzzle vertical. o Rest the trigger hook of the standard trigger
weight hanger on the trigger where the
average finger would normally rest, making sure it is not
touching any other part of the firearm, with the weights hanging
parallel to the bore of the firearm.
o Add weights until the weights pull the trigger through the
double action sequence and the sear releases.
o Check two or three times, resetting the sear connection after
each attempt. Record the heaviest weight at which the sear will
hold and not release. Record the lightest weight necessary to cause
consistent sear release. This will be the trigger pull range. Note
any revolver cylinder chamber that alters the trigger pull.
o It should be noted that measuring the trigger pull of a
rimfire firearm should not be performed on an empty chamber. A
“dummy” cartridge should be used. The
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examiner must also take into consideration the potential for
damage of a centerfire firearm and may wish to use a “dummy”
cartridge in this instance as well.
• SINGLE ACTION TRIGGER PULL WITH SPRING GAUGE o Insure that the
firearm is unloaded. o Cock the firearm. o Hold the firearm with
the muzzle parallel to the spring gauge. o Insure the Spring Gauge
indicator is “zeroed”. o Rest the trigger hook of the Spring Gauge
on the trigger where the average finger
would normally rest. Make sure it is not touching any other part
of the firearm and the Spring Gauge is parallel to the bore of the
firearm.
o Apply pressure to the Spring Gauge, until the sear releases. o
Check two or three times, resetting the sear connection after each
attempt. o Record the lightest weight(s) necessary for sear
release. o Note any revolver cylinder chamber that alters the
trigger pull. o It should be noted that measuring the trigger pull
of a rimfire firearm should not be
performed on an empty chamber. A “dummy” cartridge should be
used. The examiner must also take into consideration the potential
for damage of a centerfire firearm and may wish to use a “dummy”
cartridge in this instance as well.
• DOUBLE ACTION TRIGGER PULL WITH SRING GAUGE o Insure that the
firearm is unloaded. o Hold the firearm with the muzzle parallel to
the spring gauge. o Insure the Spring Gauge indicator is “zeroed”.
o Rest the trigger hook of the Spring Gauge on the trigger where
the average finger
would normally rest. Make sure it is not touching any other part
of the firearm and the Spring Gauge is parallel to the bore of the
firearm.
o Apply pressure to the Spring Gauge, until the sear releases. o
Check two or three times, resetting the sear connection after each
attempt. o Record the lightest weight(s) necessary for sear
release. o Note any revolver cylinder chamber that alters the
trigger pull. o It should be noted that measuring the trigger pull
of a rimfire firearm should not be
performed on an empty chamber. A “dummy” cartridge should be
used. The examiner must also take into consideration the potential
for damage of a centerfire firearm and may wish to use a “dummy”
cartridge in this instance as well.
6.1.4.2 INTERPRETATION OF RESULTS: The results acquired are only
an approximation and a different technique may lead to a different
trigger pull weight. The trigger pull is normally recorded to the
nearest ¼ pound weight increment.
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6.1.4.3 REFERENCES • Gamboe, Tom, "MAFS Firearms Workshop:
Trigger Pull Methods," AFTE Journal, Vol. 18,
No. 3, p. 77.
• Rios, Ferdinand and Thorton, John, "Static vs. Dynamic
Determination of Trigger Pull," AFTE Journal, Vol. 16, No. 3, p.
84.
6.1.5 Barrel and Overall Length Measurement of a Firearm Barrel
length is defined as the distance between the end of the barrel and
the face of the closed breechblock or bolt for firearms other than
revolvers. On revolvers, it is the overall length of the barrel
including the threaded portion within the frame. Barrel length
normally should include compensators, flash hiders, etc., if
permanently affixed. Overall length of a firearm is defined as the
dimension measured parallel to the axis of the bore from muzzle to
a line at right angles to the axis and tangent at the rearmost
point of the butt plate or grip. Removable barrel extensions, poly
chokes, flash hiders, etc., are not part of the measured barrel
length or overall length. Care must be taken if any object is
placed down the barrel to help expedite the measurement. Only a
non-marring item may be placed down the barrel, and only after all
other tests are performed.
• OTHER RELATED PROCEDURES o Physical Examination &
Classification of Firearms
• INSTRUMENTATION o Ruler (and/or) o Tape Measurer (and/or) o
Non-marring Dowel
6.1.5.1 PROCEDURE or ANALYSIS
6.1.5.1.1 BARREL LENGTH
6.1.5.1.1.1 REVOLVERS:
• Measure the distance from the breech end of the barrel to the
muzzle, excluding the cylinder. This measurement can be done
directly or by placing a non-marring item down the barrel, marking
the distance from the breech end of the barrel to the muzzle and
measuring this item.
• This measurement will be recorded in inches.
6.1.5.1.1.2 FIREARMS OTHER THAN REVOLVERS:
• Measure the distance from the breech face in a closed and
locked position to the muzzle. This measurement can be done
directly or by placing a non-marring item down the barrel, marking
the distance from the breech end of the barrel to the muzzle and
measuring this item.
• This measurement will be recorded in inches.
6.1.5.1.2 OVERALL LENGTH:
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Measure the distance from the butt to the muzzle. Measurement
shall be made parallel to the bore and recorded in inches.
• INTERPRETATION OF RESULTS: o Measurements obtained should be
considered only approximations based on the
device used to obtain the measurements.
6.1.5.2 REFERENCES • “The Proper Method for Measuring Weapons”,
AFTE Journal, Vol.14, No. 3, p. 10.
6.1.6 Rusty Firearm Examination Rusty firearms or those found in
water, etc. may be submitted for examination. Immediate attention
must be given to these firearms to prevent further damage to the
firearm. The examiner should instruct an agency recovering the
firearm in a fluid such as water, to submit the firearm in a
container of the fluid. If this is not practical, the agency can be
instructed to immediately and thoroughly spray the firearm with a
water-displacing product such as WD-40® or other similar product to
prevent further deterioration. It should be noted that the firearm
might be too rusted to be functional. Any firearm that cannot be
unloaded must be examined in an area designated for firing firearms
(preferably a range).
• OTHER RELATED PROCEDURES o Physical Examination &
Classification of Firearms
6.1.6.1 PROCEDURE or ANALYSIS • An examiner must take all
necessary steps to insure that the firearm is unloaded. If it
cannot
be readily verified to be unloaded it must be examined in an
area designated for the firing of firearms. Determining whether or
not a firearm is unloaded may necessitate a complete disassembly or
in some cases, destruction (e.g. cutting)
• The examiner must determine to what extent restoring the
firearm is necessary (i.e., for test firing, for recovering
manufacturer information, serial number, etc.).
• Soak the firearm in penetrating oil, de-rusting solvents or
similar material.
• Periodically check the firearm until the firearm functions, or
the desired information is recovered. Clean the firearm with gun
cleaning solvent, cleaning patches and cloth. Care must be taken if
any object is placed down the barrel. Only a non-marring item
should be placed down the barrel.
6.1.6.2 REFERENCES • Denio, Dominic, "Making a Rusted Gun
Functional," AFTE Journal, Vol. 13, No. 3, p. 29
6.1.7 Sound Suppressor Examination A silencer or sound
suppressor is any device attached to the barrel of a firearm
designed to reduce the noise of discharge. Silencers can be
commercially produced or homemade. They are typically tubular metal
devices, but may vary in shape or form.
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• OTHER RELATED PROCEDURES o Safe Firearm Handling o Physical
Examination & Classification of Firearms
6.1.7.1 PROCEDURE or ANALYSIS • Examine device to determine if
it is, or is characteristic of, a silencer or sound suppression
device.
• Examiner will document and record his/her findings.
• After an initial examination, a report can be issued that the
device is, or is characteristic of, a silencer or sound suppression
device.
• Testing of a firearm and firearm/silencer combination must be
conducted in an appropriate setting, usually a range.
• In many instances the noticeable reduction in sound between
the firing of the firearm with the device attached vs. the firing
of the firearm without the device is sufficient to determine that
the device is a sound suppressor.
6.1.7.2 REFERENCES • Silencers - A Review And A Look At The
State Of The Art," AFTE Journal, Vol. 23, No. 2,
p. 668.
• Crum, Richard A. and Owen, Edward M., "Silencer Testing," AFTE
Journal, Vol. 21, No. 2, p. 433.
6.1.8 Malfunctioning Firearm Examination A firearms examiner may
be called upon to examine a firearm to determine if the firearm
will malfunction. Many of these cases will deal with the question:
"Will the firearm fire without pulling the trigger?" In these
instances it should be the goal of the examiner to acquire a
detailed account of the incident by thoroughly examining and
testing the firearm. Examinations may include external and internal
observations, or striking or dropping the firearm in attempts to
duplicate the incident as reported. The examiner should attempt to
conduct his/her examinations in a manner so as not to alter the
firearm. However, there may be occasions when damage may occur. Any
change to the firearm must be specifically documented in the
examiner’s notes.
• OTHER RELATED PROCEDURES o Safe Firearm Handling o Primed
Cases
6.1.8.1 PROCEDURE or ANALYSIS No one procedure can sufficiently
outline the steps necessary to examine all firearms for any
malfunction. However, the following list of examinations should
serve as a guideline for the examiner.
• Physical Check (Condition of Firearm as Received):
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o Cocked/Uncocked o Safety position o Loaded/Unloaded o
Cartridge Position o Stuck Cartridges/Discharged Cartridge Cases o
Presence and/or location of flares
• Visual Abnormalities: o Barrel (loose, etc.) o Receiver
(condition) o Slide (condition) o Parts broken or missing
especially:
The firing pin The ejector or The extractor
o Screws (loose or missing) o Alterations or adaptations o
Sights o Action (External)
Relationships of the action parts o Correct assembly
The proper locking of the action on closing Cylinder rotation
(securely locks) Hand relationship to the ratchet (worn) Trigger
pull (single action, double action) and striking of hammer.
o Safeties: (Drop hammer several times to check below safeties.)
¼ , ½ , Full Cock, Seating check (any false seating positions, pull
off/push off,
etc.)
Grip, magazine, disconnector: function Thumb/Finger – note
positions when firearm will fire Rebound hammer or inertia firing
pin Position of the slide or bolt in order to fire Condition of
safeties
o Action Check
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o Check feeding Magazine Carrier or lifter Feed Ramp Magazine
lips, etc.
o Slamfire Extractor and/or Ejector markings on evidence
cartridges/discharged cartridge
cases
Unusual marks exhibited on the cartridges/discharged cartridge
cases. Check for any inherent “quirks” known about the particular
firearm based on
literature or case data.
o Test Fire Firearm (note operation, misfires, etc.): Note any
operational problems Ammunition involved (proper cartridge, type,
reloads, etc.). Check consistency of the impression on test and
evidence.
• Special Situational Tests:
• Care should be exercised when the force to be used in testing
could alter or damage internal parts and their working
relationship(s). Damage caused by the examiner may prevent the
examiner from determining the cause of the reported
malfunction.
• Action (Internal) o Hammer Notch(s)
Worn Burrs Dirt, etc.
o Sear Worn Broken Burrs, etc
o Safeties (relationships and general parts relationship) Broken
Altered,etc Signs of any tampering or faulty assembly.
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6.1.8.2 REFERENCES • Thompson, Roger C., "Firearms Malfunction
Worksheets," AFTE Journal, Vol. 15, No. 1, p.
100.
• American National Standards Institute, Inc., “American
National Standard Voluntary Industry Performance Standards Criteria
for Evaluation of New Firearms Designs Under Conditions of Abusive
Mishandling for the Commercial Manufacturers”. (ANSI/SAAMI
Z299.5-1985), November, 1985.
6.1.9 Firearms Reference Library A Firearms Reference Library,
File or Collection is maintained by the laboratory for various
scientific reasons, to include:
• To identify the make, model and source of evidence
firearms.
• To provide exemplar firearms for various scientific testing
purposes which might otherwise compromise an evidence firearm.
• To provide an exemplar resource for training new forensic
scientists/evidence technicians or in developing new technology for
the scientific examination of firearms.
• To provide a source of firearms parts for the temporary repair
of evidence firearms for test-firing purposes.
• To provide a resource for the identification of firearms parts
recovered at a crime scene.
• To provide a resource for the location and style of firearm
serial numbers.
• OTHER RELATED PROCEDURES o Safe Firearm Handling o Ammunition
Reference Collection
6.1.9.1 PROCEDURE or ANALYSIS A Firearms Reference Library must
be maintained under strict regulations and controls. Firearms,
which are deemed unsuitable for scientific purposes, should be
verifiably destroyed. The laboratory assumes all responsibility for
security, control and destruction of these firearms.
A written record should be made immediately upon receipt of a
firearm, intended for the reference collection, in a “FIREARM LOG”.
This entry should initially include;
• the log number assigned.
• the date received.
• the submitting agency or source of the firearm.
• the receivers initials. The “FIREARM LOG ” may be produced
electronically by spreadsheet. The following data columns may be
used in the firearm log books. It is suggested that these columns
be kept in the same order as listed below with the log number being
the first entry on the left side of the spreadsheet.
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• LOG NUMBER: o Assigned by the receiving laboratory at the time
of receipt of the firearm.
• DATE RECEIVED: o Date received at the laboratory.
• AGENCY or SOURCE: o The agency or person transferring control
of the firearm to the laboratory.
• CALIBER: o Caliber or gauge of the firearm.
• MANUFACTURER: o Make, brand and manufacturer, if known.
• MODEL: o Model number(s) and/or name.
• TYPE: o Type of action.
• FINISH: o Finish on firearm.
• BARREL LENGTH: o The barrel length of the firearm.
• SERIAL NUMBER: o The serial number as stamped on the firearm.
“NONE” if the serial number does not
exist or cannot be found. OBLIT if the serial number has been
obliterated.
• COMMENTS: o Notes regarding transfers, destruction, location
case numbers, etc.
It is recommended that a receipt be issued for every firearm
received for the reference library or destruction utilizing a
standardized form. The respective log number assigned to each
firearm should be recorded on this form. These forms should be
maintained in some reasonable order.
Firearms reference library should be displayed and maintained in
such a manner as to prevent the firearms deterioration and to
facilitate their inventory, safety and control.
All firearms received for reference or disposal should have
their assigned log number inscribed on the frame and/or receiver.
Furthermore, all firearms placed in the reference library should be
tagged in such a manner so as to display that firearm’s location
within the collection.
It is recommended that a system, whether it be a card file, or a
computer data base also be maintained. This will facilitate
cross-referencing the collection between various fields.
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Great care must be given if the section decides to maintain only
a computer database. The historical archive that a Log provides and
the difficulty to alter records within a Log must be
considered.
6.1.9.2 REFERENCES • AFTE Glossary, 3rd Edition
6.1.10 Test Firing and Recovery of Test Fires In order to
perform a microscopic comparison of a submitted firearm, a minimum
of two (2) test shots should be fired and recovered. Recovery
methods include the water tank, and the cotton waste recovery box.
The type of firearm and ammunition tested will usually dictate the
type of recovery method used. The water recovery tank is usually
used to recover bullets from handguns, rifles and slugs fired from
shotguns. The cotton waste recovery box is usually used to recover
bullets from handguns, rifles and slugs fired from shotguns. The
indoor firing range is usually used to test fire firearms when the
recovery of the fired projectile(s) is not necessary. One should be
aware of the maximum velocity of the projectile that can be fired
into a particular water tank, as well as the proper water depth
needed for firing. One should be aware of the maximum velocity of
the projectile that can be fired into a particular cotton waste
recovery box.
• OTHER RELATED PROCEDURES o Safe Firearm Handling o Downloading
o Primed Cases
MINIMUM ANALYTICAL STANDARDS and CONTROLS Test fired bullet and
cartridge case samples are to be treated as reference material
only. If a test fired bullet/cartridge case is used for comparison
purposes at a later date, it will be documented on the examiner’s
report as being a reference bullet/cartridge case previously test
fired in the firearm and retained at the Arkansas State Crime
Laboratory.
o Test fire reference collections will be maintained in a secure
area accessible by Firearms Section personnel. Archived material
will be stored in a secure area in the ASCL Annex.
6.1.10.1 PROCEDURE or ANALYSIS • A test fire information card
will be filled out to include the ASCL case #, item # and
identifying information (if available) for the test firearm. The
test fire information card will be stored with the test fired
bullets and cartridge cases.
• The examiner should consider marking the bullet and cartridge
case of each test shot with the;
o Full or abbreviated laboratory case number and o Full or
abbreviated item number and/or o examiner's initials.
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• If the examiner does not, or is unable to, mark the test fired
bullet/cartridge case with the above information, then the package
containing the test fires and information card will be sealed and
initialed.
• The examiner should consider indexing and sequencing each shot
and perform these functions if necessary.
• Proper hearing and eye protection must be worn.
• Ensure that the Exhaust fans or system is turned on.
• Ensure all warning systems are activated.
• The examiner should consider the number of cartridges being
loading into the firearm during the initial testing of the
firearm.
• Ejected discharged cartridge cases must be retrieved.
• For Water Tank Recovery o Ensure that the water level is
appropriate. o Ensure that all lids or doors of the water recovery
tank are closed and properly
secured.
o Fire the firearm through the shooting port. If the firearm is
capable of firing both single and double action modes, a minimum of
one (1) shot per mode should be obtained.
o Recover the bullets using the vacuum tube.
• For Cotton Waste Recovery Box o The examiner should consider
wetting the first section of cotton in the box. o The examiner
should consider the placement of paper partitions at various points
in
box to ensure tracking of the test shot, as well as insuring
that the cotton is packed down so as not to retain previous bullet
paths.
o Ensure that all lids or doors of the box are closed and
properly secured. o Fire the firearm through the shooting port. If
the firearm is capable of firing both
single and double action modes, a minimum of one (1) shot per
mode should be obtained.
o Bullets should be recovered by searching through cotton, using
partitions as guides.
• For Indoor Firing Range o If the firearm is capable of firing
both single and double action modes, a minimum of
one (1) shot per mode should be obtained.
o The examiner should check the range to make sure no materials
are left behind.
• For Remote Firing o Set up the chosen remote firing device, as
per guidelines set forth by the
manufacturer, in front of the appropriate recovery system.
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o Place firearm in device. It is recommended that the examiner
first dry-fire the firearm in the remote firing device before using
live ammunition.
o Activate the remote device while standing behind a protective
shield or while standing at a safe distance away from the
firearm.
o Obtain fired tests.
6.1.10.2 REFERENCES • Newquist, Andrew M., “New Bullet Recovery
System”, AFTE Journal, February 1973, p.9.
• Molnar, S., “A Novel Bullet Recovery Method”, AFTE Newsletter,
16, p.17.
• Operators Manual, Water Recovery Tank, CyberNational Inc.
• “Bullet and Cartridge Case Recovery”, AFTE Journal, Vol. 16,
No. 2, p.75.
• McBrayer, William S., "What? Another Water Tank and Bullet
Stop!", AFTE Journal, Vol. 10, No. 2, p.90.
• Biasotti, A. A., "Vise/Rest for Remote Firing," AFTE Journal,
Vol. 11, No. 4, p.16.
6.1.11 Downloading Due to the limitations of a firearms
identification section's bullet recovery devices, it may be
necessary to reduce or change the powder load of the cartridge in
order to obtain a velocity suitable for safely collecting test
standards for comparison purposes. Even with a reduced load, it may
be necessary to fire the firearm remotely.
• OTHER RELATED PROCEDURES o Safe Firearm Handling o Test Firing
and Recovery of Test Fires o Primed Cases
• INSTRUMENTATION o Balance / Scale
6.1.11.1 PROCEDURE or ANALYSIS Pull the bullet of the cartridge
using an inertia bullet puller or a reloading press.
Remove existing powder.
Weigh the pulled bullet.
Consult a reloading manual, such as Lyman, and obtain the powder
charge for the weight of the pulled bullet and the new velocity
needed.
Weigh out the appropriate powder charge and place in existing
cartridge case.
Loosely pack a small piece of tissue or other similar material
into the case to fill the gap between the bullet and powder.
Seat the bullet back into the cartridge case using a rubber
mallet or a reloading press.
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If appropriate powder is not available, a reduced load using 50%
of the original powder can be used. It should be noted that great
care must be taken when performing this type of downloading. 50%
downloading CANNOT be used with slow burning powders. 50%
downloading CANNOT be used with many non-canister powders.
When utilizing downloaded ammunition it is imperative that the
examiner checks the barrel for obstructions between each firing.
The bullet, cartridge case, or shotshell of each test shot should
be marked appropriately.
6.1.11.2 REFERENCES • Lyman Reloading Handbook for Rifle, Pistol
and Muzzle Loading, Lyman Gun Sight
Products, Middlefield, Conn., 1971.
• "Reduced Powder Loads," AFTE Newsletter, No. 3, p.14.
6.1.12 Primed Cartridge Case/Shotshell During the course of
examining a firearm, it may be determined that it would be unsafe
for the examiner to fire the firearm as designed. If it is not
necessary to obtain test standards for comparison purposes, the
firing condition of the firearm can be tested using a primed empty
cartridge case or shotshell.
• OTHER RELATED PROCEDURES o Safe Firearm Handling o Bullet
Trap
6.1.12.1 PROCEDURE or ANALYSIS Obtain a primed empty cartridge
case in the desired caliber or pull the bullet of a live cartridge
using an inertia bullet puller or reloading press, retaining only
the primed cartridge case. For shotguns, obtain a primed empty
shotshell in the desired gauge or cut open a live shotshell
removing all components, retaining only the primed shotshell.
• Commercial firing pin testing devices are available for
shotguns and may be used. Proper hearing and eye protection must be
worn.
Ensure that the Exhaust fans or system is turned on.
Ensure all warning systems are activated.
Load the primed empty cartridge case, primed empty shotshell or
commercial firing pin testing device into the chamber of the
firearm and test fire in front of the bullet trap.
When utilizing a primed empty it is imperative that the examiner
check the barrel for obstructions between each firing.
Repeat if the firearm has more than one action.
Obtain all tests.
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6.1.13 Caliber Determination Caliber, or the base diameter, is
one of the class characteristics of a fired bullet. The
determination of caliber will aid the examiner during the
identification or elimination of a suspect firearm. If no firearm
is submitted, the bullet's caliber may be used in determining the
General Rifling Characteristics of the firearm involved.
• OTHER RELATED PROCEDURES o Trace Material Examination o GRC
Utilization
• INSTRUMENTATION o Comparison Microscope o Stereo Microscope o
Calipers/Micrometer o Measuring Projector
6.1.13.1 PROCEDURE or ANALYSIS The following may be utilized to
determine the caliber of any fired bullet. The condition of the
bullet will determine which steps can be used.
• Compare the base diameter of the evidence bullet directly with
known fired test standards.
• Measure the base diameter of the evidence bullet using a
measuring device and compare this measurement with known
measurements published in reference literature.
• Determine the number and widths of the lands and grooves and
compare to Appendix G, Table 6, of the AFTE Glossary (current
edition is available on the AFTE website).
• Physical characteristics of the evidence bullet, such as
weight, bullet shape, composition, nose configuration, and number
and placement of cannelures, may aid in caliber determination.
6.1.13.2 INTERPRETATION OF RESULTS: Caliber is written as a
numerical term and will be depicted with the decimal point when
applicable. If the base is mutilated, the examiner may only be able
to determine that the evidence is consistent with a range of
calibers or that the caliber cannot be determined.
6.1.13.3 REFERENCES • Mathews, J. Howard, Firearms
Identification Vol. I, 1973.
• Barnes, Frank C., Cartridges of the World, 7th Edition,
1993.
• Association of Firearm and Toolmark Examiners Glossary, 3rd
Edition, 1994.
• Lutz, Monty C. and Ward, John G., "Determination of Bullet
Caliber From an X-ray," AFTE Journal, Vol. 21, No. 2, p. 168.
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6.1.14 Measuring Land Impression and Groove Impression Widths
One of the class characteristics used in the discipline of firearms
identification is the width of the land impressions and groove
impressions. These measurements aid the examiner during the
identification or elimination of a suspect firearm. If no firearm
is submitted, these measurements will be used in determining the
General Rifling Characteristics of the firearm involved. The
measuring projector procedure utilizes an MP-6 Measuring Projector
or equivalent. The comparison microscopes have specific software
for measurements. The air gap procedure utilizes a comparison
microscope and a micrometer.
• OTHER RELATED PROCEDURES o Trace Material Examination o GRC
Utilization
• INSTRUMENTATION o Measuring Projection Scope o Comparison
microscope o Software for the Comparison Microscope o Stereo
Microscope o Ruler/Micrometer
6.1.14.1 PROCEDURE or ANALYSIS In measuring a fired bullet to
determine the width of the land impression or the groove
impression, it is paramount that the points used for beginning and
ending a measurement comply with the discipline-wide practice. This
practice utilizes the anchor points shown below.
• For the Measuring Projection Scope:
o The fired bullet in question is mounted in the measuring
projector's bullet holder. o The land impression of the fired
bullet is placed in a horizontal position with one of
the anchor points corresponding with the measuring projector's
alignment grid.
o Zero the direct reading scale of the measuring projector.
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o Rotate the micrometer, thereby moving the fired bullet
laterally, until the next anchor point is reached and record the
measurement in thousandths of an inch or to the appropriate
measurement standard for the local laboratory.
o Repeat this procedure for the groove impression. o For
specific operating instructions on the instrument utilized, consult
the operator's
manual.
• For the Comparison Microscope using Software o The fired
bullet in question is mounted in the microscope bullet holder. o
(For the FSC microscope) The land impression of the fired bullet is
placed in a
horizontal position with one of the anchor points corresponding
with the measuring alignment mark.
o For the FSC using the Palm emulator and a live image, select
the left or right stage position on the PALM emulator, select START
and move the fired bullet stage laterally, until the next anchor
point is reached and record the measurement in thousandths (mils)
of an inch from the PALM emulator.
o (For the SPOT software) Take a photograph of the desired image
with the land impression or groove impression visible.
o (SPOT software) Draw a measurement line over the portion of
interest.. Record the measurement in thousands of an inch.
o Repeat this procedure for the groove impression. o For
specific operating instructions on the instrument utilized, consult
the operator's
manual.
• For Air Gap o The fired bullet in question is mounted on one
stage of the comparison microscope.
The micrometer is mounted on the other stage.
Both stages must be using the same magnification level
(objective setting) and be in focus.
o Align the image of the measurement gap (opening) of the
micrometer with the image of the appropriate land impression being
measured and record the measurement to the nearest hundredth or
thousandth of an inch or appropriate measurement.
o Repeat the above utilizing the groove impression.
• For the Stereo Microscope with a ruler/micrometer o The fired
bullet in question is either held or mounted on a steady surface
beneath the
stereo microscope.
o The land impression at the base of the fired bullet is placed
perpendicular to the scale of the ruler.
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o Measure the distance between both anchor points of a land
impression and record the measurement to the nearest hundredth or
thousandth of an inch or appropriate measurement.
o Repeat the above utilizing the groove impression.
6.1.14.2 INTERPRETATION OF RESULTS: It may be necessary to
measure several of each land and groove impression in order to
record a reliable measurement.
6.1.14.3 REFERENCES • U.S. Department of Justice, Federal Bureau
of Investigation, NCIC, Criminalistics
Laboratory Information System (CLIS) Operating Manual, 1978.
• Unitron MP-6 Operating Manual.
• Leica FSC Operating Manual.
• Leica UFM-4 Operating Manual
• SPOT Operating Manual by Diagnostic Instruments
• Leica Application Suite Software
• Walsh, J. F., "Accuracy, Speed and Conversion in Rifling
Measurements," AFTE Journal, Vol. 9, No. 1, p. 50.
• AFTE Newsletter, No. 4, December 1969, p. 28.
6.1.15 National Integrated Ballistic Information Network The
National Integrated Ballistics Information Network (NIBIN) is a
computerized system for acquiring and storing the images of
unidentified bullets and cartridge cases as well as known bullets
and cartridge cases. NIBIN images portions of the surface (land
engraved areas) of a bullet and the primer/firing pin and ejector
areas of fired cartridge cases using state of the art optical and
electronic technology. These images are then stored in databases
and sophisticated algorithms are used to correlate the images
against each other using filters such as caliber, rifling
specifications, date of crime and date of entry. These correlations
produce lists of possible matches with the highest score at the top
of the list. A firearms examiner or NIBIN technician can then call
up the images to compare them side by side on a monitor. If a
possible association is found during this screening process then
the physical items are compared by a firearms examiner utilizing
traditional comparative microscopy techniques. A new employee with
the Firearms and Tool Marks section (or subsection Operation
Shutdown) cannot use the NIBIN technology until they have been
properly trained and received clearance through Forensic
Technologies, Inc. and the Bureau of Alcohol, Tobacco, Firearms and
Explosives (ATF). Cautions pertaining to electrical equipment and
computer storage media should be observed by anyone utilizing the
NIBIN technology.
• OTHER RELATED PROCEDURES o Examination and Physical
Classification of Fired Evidence o Examination and Physical
Classification of Fired Cartridge Cases
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o Examination and Physical Classification of Fired Shotshells o
Microscopic Comparison
• PREPARATION o Cartridge Case – The examiner should consider
marking the sides of the cartridge
case to indicate where the extractor and/or ejector markings are
for proper alignment.
o Bullet - Mount the bullet in the designated holder with a glue
gun as outlined in the IBIS Training Course student handbook.
• INSTRUMENTATION o Remote Data Acquisition System (RDAS).
• MINIMUM ANALYTICAL STANDARDS and CONTROLS o In accordance with
ASCLD 1.4.1.6 (E), the NIBIN bullet and cartridge case samples
are to be treated as reference material only. If a test fired
bullet/cartridge case is used for comparison purposes at a later
date, it will be documented on the examiner’s report as being a
reference bullet/cartridge case previously test fired in the
firearm and retained at the Arkansas State Crime Laboratory.
• Test fired bullet and cartridge case reference samples will be
maintained in a secure area accessible by Firearms Section
personnel. Archived material will be stored in a secure area in the
ASCL Annex.
6.1.15.1 PROCEDURE or ANALYSIS • A test fire information card
will be filled out to include the ASCL case #, item # and
identifying information (if available) for the test firearm. The
test fire information card will be stored with the test fired
bullets and cartridge cases.
• The examiner should consider marking the bullet and cartridge
case of each test shot with the;
o Full or abbreviated laboratory case number and o Full or
abbreviated item number and/or o examiner's initials.
• If the examiner does not, or is unable to, mark the test fired
bullet/cartridge case with the above information, then the package
containing the test fires and information card will be sealed and
initialed.
• Cartridge Case – Using the RDAS, open the BRASSCATCHER
software and enter the specimen information as outlined in the RDAS
operators’ manual or the IBIS Training Course student handbook.
• Bullet – Using the RDAS, open the BULLETPROOF software and
enter the specimen information as outlined in the RDAS operator’s
manual or the IBIS Training Course student handbook.
• The examiner must therefore insure that;
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o Any evidence bullet selected for entry into NIBIN must have at
least one clear and distinct land engraved area and must have
sufficient individual characteristics to be able to affect a
match.
o Any evidence cartridge case selected for entry into NIBIN must
have sufficient individual characteristics within the firing pin
impression and/or within the breech face marks on the primer to
affect a match.
o If there are more than one matching evidence bullets and/or
cartridges cases suitable for entry into NIBIN, the examiner should
select the best one for entry or, if necessary, more than one if
different individual characteristics reproduce better on different
tests.
o Any information about the identification of evidence
bullets/cartridge cases to each other and the selection of certain
specimens for entry into NIBIN must be documented within the case
notes.
• For Firearms requests, a notification of entry into the NIBIN
system will be included in the examiner’s report.
• For Operation Shutdown requests, a NIBIN Evidence Evaluation
Form (FA-FORM-05) will be completed and attached to evidence that
has been processed/evaluated for entry into the NIBIN system.
6.1.15.2 REFERENCES • RDAS OPERATORS MANUAL
• IBIS Training Course Student Handbook
6.1.16 GRC Utilization The FBI's General Rifling Characteristics
File can be utilized when attempting to determine a list of
possible firearms that could have fired an evidence bullet when the
correct firearm was not submitted.
• OTHER RELATED PROCEDURES o Trace Material Examination o
Measuring Land Impression and Groove Impression Widths
6.1.16.1 PROCEDURE or ANALYSIS The General Rifling
Characteristics File can be accessed using the PC software version,
or the current printout of the file.
Follow the operating instructions listed specifically within
each of the above systems utilizing the caliber and rifling
characteristics of the evidence bullet.
6.1.16.2 INTERPRETATION OF RESULTS: The GRC File is an
investigative aid and should not be construed as an all-inclusive
list of firearms available with those particular rifling
characteristics.
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6.1.16.3 REFERENCES • U.S. Department of Justice, Federal Bureau
of Investigation, NCIC, Criminalistics
Laboratory Information System (CLIS) Operating Manual, 1978.
• Walsh, J. F., "Accuracy, Speed and Conversion in Rifling
Measurements," AFTE Journal, Vol. 9, No. 1, p. 50.
• AFTE Newsletter, No. 4, December 1969, p. 28.
6.1.17 Wadding Determination By examining wadding, the examiner
may be able to determine the gauge size, manufacture, and if the
wad contains markings suitable for comparison, the firearm that
discharged it.
• OTHER RELATED PROCEDURES o Trace Material Examination o
Measuring Land Impression and Groove Impression Widths
• INSTRUMENTATION o Comparison Microscope o Stereo Microscope o
Micrometer o Caliper o Measuring Projector
6.1.17.1 PROCEDURE or ANALYSIS • Determine gauge size by;
o Directly comparing the evidence to known laboratory standards
of similar manufacture or composition by comparing the base of
evidence to the bases of the standards until a similar size is
found.
o Gauge size can also be determined by measuring the base
diameter of the wad and comparing these measurements to known
measurements.
• Measurements may be obtained by utilizing a; o Caliper o The
air gap o The stereo microscope with ruler/micrometer/caliper o The
measuring projector.
• Manufacturers’ data can be determined by locating information
stamped into the wad or by comparing the wad to known laboratory
standards.
• Microscopic examination may reveal striations suitable for
identification of the wad back to the shotgun that fired it.
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• If evidence shotshells are submitted, it may be necessary to
disassemble one for the determination of gauge size or
manufacturer.
• Record all information on the appropriate worksheet.
6.1.17.2 INTERPRETATION OF RESULTS: If the wad is mutilated or
soaked with blood or other body fluids, the examiner may not be
able to specifically determine gauge size. The examiner should also
recognize that some manufacturers might duplicate the design of
another manufacturer.
6.1.18 Shot Determination By examining recovered shot pellets,
the examiner may be able to determine the actual shot size. The
determined size can then be compared to the shot size loaded in
submitted live shotshells or to the size that the submitted
discharged shotshell was marked to have contained.
• OTHER RELATED PROCEDURES o Trace Material Examination o
Measuring Land Impression and Groove Impression Widths
• INSTRUMENTATION o Comparison Microscope o Stereo Microscope o
Micrometer o Caliper o Measuring Projector
6.1.18.1 PROCEDURE or ANALYSIS The examiner may use one or all
of the below techniques to determine shot size.
• Visual/Microscopic Comparison o Determine the total number of
pellets received. o Determine the composition of the pellets. o
Determine the number of pellets suitable for comparison purposes.
Make note if
pellet sizes all appear to be similar in size. If several
different sizes are present, determine each specific size.
o Compare laboratory standards of known shot sizes side by side
with the evidence pellets until a known shot size is determined. A
stereo microscope may aid in this determination. This can be done
one size at a time or several sizes at a time; however, if more
than one size is used at a time, care should be taken not to mix up
the shot.
o Record findings on worksheet.
• Comparison by Weight
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o Record the total number of pellets received. o Determine the
composition of the pellets. o Determine the number of pellets
suitable for weighing. Make note if pellet sizes all
appear similar. If several sizes present, determine each
specific size.
o Weigh the pellets in grams or grains. o Divide weight of
pellets by total number weighed. o Consult known pellet weights in
Table 1 of Appendix G of the AFTE Glossary (3rd
Edition) and determine shot size, which corresponds to evidence
shot.
o The weight of the evidence pellets can also be directly
compared to weight of standards using the same number of pellets
until a similar known weight is obtained.
• Measuring Pellet Size o Determine the total number of pellets
received. o Determine the composition of the pellets. o Determine
the number of pellets suitable for comparison purposes. Make note
if
pellet sizes all appear to be similar in size. If several
different sizes are present, determine each specific size.
o Choose the best specimen and measure diameter using a caliper
and record in hundredths or thousandths of an inch or the
appropriate measurement.
o Consult known pellet sizes in Table 1 of Appendix G of the
AFTE Glossary (3rd Edition) and determine shot size, which
corresponds to evidence shot.
6.1.18.2 REFERENCES • Association of Firearm and Toolmark
Examiners Glossary, 3rd Edition, 1994.
6.1.19 Physical Examination & Classification of Fired
Bullet/Slug Evidence The initial examination of any fired
bullet/slug evidence will include the completion of a worksheet.
These worksheets will include the physical description of the fired
evidence and will serve as a source to document the condition of
the evidence as received and any tests or comparisons
performed.
• OTHER RELATED PROCEDURES o Trace Material Examination o
Measuring Land Impression and Groove Impression Widths o Caliber
Determination
• INSTRUMENTATION o Comparison Microscope o Stereo Microscope o
Micrometer
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o Caliper o Measuring Projector o Scale/Balance
6.1.19.1 PROCEDURE or ANALYSIS A worksheet will be filled out
according to the appropriate Appendices. This may include noting
the following:
• If any trace material is present.
• The caliber.
• The bullet/slug weight should be measured in grains.
• The number of lands and grooves on a fired bullet.
• The direction of twist.
• The measured width of the land impressions.
• The measured width of the groove impressions.
• The composition of the bullet/slug.
• The bullet style.
• The possible manufacturer/marketer of the
bullet/slug/projectile.
• A description of the base of the bullet.
• The type and position of cannelures.
• Any extraneous markings to include: o Skid Marks o Shave Marks
o Flared Base o Other Marks
• The presence of gunpowder and/or powder imprints adhering to
the base.
• The condition of the fired evidence as received.
• The suitability of the fired evidence for comparison
purposes.
6.1.19.2 REFERENCES • Howe, Walter, J., “Laboratory Work Sheets”
AFTE NEWSLETTER NUMBER TWO,
August 1969, p.13.
• Association of Firearm and Toolmark Examiners Glossary, 3rd
Edition, 1994.
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6.1.20 Physical Examination & Classification of Fired
Cartridge Cases The initial examination of any fired cartridge case
evidence will include the completion of a worksheet. These
worksheets will include the physical description of the fired
cartridge case and will serve as a source to document the condition
of the evidence as received and any tests or comparisons
performed.
• OTHER RELATED PROCEDURES o Trace Material Examination o
Measuring Land Impression and Groove Impression Widths o Caliber
Determination
• INSTRUMENTATION o Comparison Microscope o Stereo Microscope o
Micrometer o Caliper o Measuring Projector o Scale/Balance
6.1.20.1 PROCEDURE or ANALYSIS A worksheet will be filled out
according to the appropriate Appendices and individual laboratory
policy. This may include noting the following:
• If any trace material present.
• Caliber
• The possible manufacturer/marketer of the item.
• Ignition System o Centerfire o Rimfire o Other
• Shape of cartridge case.
• Description of cartridge case and primer.
• Description of head stamp
• Description of Firing Pin Impression
• Description of other markings, to include: o Breech Face
Markings o Extractor
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o Ejector o Resizing Marks o Chamber Marks o Anvil Marks o
Magazine Marks o Ejection Port Markings o Other Marks
6.1.20.2 REFERENCES • Howe, Walter, J., “Laboratory Work Sheets”
AFTE NEWSLETTER NUMBER TWO,
August 1969, p.13.
• Association of Firearm and Toolmark Examiners Glossary, 3rd
Edition, 1994.
6.1.21 Physical Examination & Classification of Fired
Shotshells The initial examination of any fired shotshell evidence
will include the completion of a worksheet. These worksheets will
include the physical description of the fired shotshell and will
serve as a source to document the condition of the evidence as
received and any tests or comparisons performed.
• OTHER RELATED PROCEDURES o Trace Material Examination o
Measuring Land Impression and Groove Impression Widths o Caliber
Determination
• INSTRUMENTATION o Comparison Microscope o Stereo Microscope o
Micrometer o Caliper o Measuring Projector o Scale/Balance
6.1.21.1 PROCEDURE or ANALYSIS A worksheet will be filled out
according to the appropriate Appendices. This may include noting
the following:
• If any trace material is present.
• Gauge/Bore/Caliber
• The possible manufacturer/marketer of the item.
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• Ignition System o Centerfire o Rimfire o Other
• Shape of the shotshell.
• Description of the shotshell and primer.
• Description of the head stamp.
• Description of the Firing Pin Impression.
• Description of other markings, to include: o Breech Face
Markings o Extractor o Ejector o Resizing Marks o Chamber Marks o
Anvil Marks o Magazine Marks o Ejection Port Markings o Other
Marks
6.1.21.2 REFERENCES • Howe, Walter, J., “Laboratory Work Sheets”
AFTE NEWSLETTER NUMBER TWO,
August 1969, p.13.
• Association of Firearm and Toolmark Examiners Glossary, 3rd
Edition, 1994.
6.1.22 Subclass Characteristics When examining an item of fired
evidence it is important for the examiner to evaluate the markings
observed for potential subclass characteristics. Caution should be
exercised in distinguishing subclass characteristics from
INDIVIDUAL CHARACTERISTICS. Subclass characteristics are
discernible features of an object which are more restrictive than
CLASS CHARACTERISTICS in that they are:
• Produced incidental to the manufacturing process. • Are
significant in that they relate to a smaller group source (a subset
of the class to which
they belong). • Can arise from a source which changes over time.
• Examples may include: bunter marks, broach cut marks, concentric
circled breech face
marks, etc.
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6.1.23 Microscopic Comparison In order for an examiner to
identify an item of fired evidence back to the firearm that
produced it, a microscopic comparison utilizing a comparison
microscope must be performed. The comparison microscope allows the
examiner to place the evidence on one side of the microscope and
the known standard on the other side. This procedure may also be
used to compare two unknown pieces of fired evidence together to
determine if they were made by the same firearm.
• OTHER RELATED PROCEDURES o Examination and Physical
Classification of Fired Evidence o Examination and Physical
Classification of Fired Cartridge Cases o Examination and Physical
Classification of Fired Shotshells o Trace Material Examination
• INSTRUMENTATION o Comparison Microscope o Stereo
Microscope
6.1.23.1 PROCEDURE or ANALYSIS The procedure steps below do not
have to be performed in the order listed; however, all steps must
be considered and/or addressed:
• Select the correct objective (magnification) setting and
ensure that the objectives are locked in place.
• Select the correct set of oculars (eyepieces).
• The illumination (lights) used must be properly adjusted.
Oblique lighting is usually preferred.
• If a firearm is included as part of the evidence, compare the
test shots produced from this firearm to determine what microscopic
c