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Firearms Examiner Training

Module 10: Characterization and Evaluation of Fired Projectiles

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illustration of a gun being fired
National Institute of Justice (NIJ) (see reuse policy).


Author: John H. Dillon, Jr.
Headshot of Author John H. Dillon, Jr
National Institute of Justice (NIJ) (see reuse policy).
Jack Dillon earned a B. S. from the United States Naval Academy and an M. Ed. from the University of Virginia. Commissioned in the United States Marine Corps in 1964, he attained the rank of Captain of Marines. Appointed a Special Agent, FBI, in 1970, he investigated diverse criminal violations, including organized crime, bank robberies, extortions, and kidnappings. In 1976 he received orders to the Firearms/Toolmarks Unit of the FBI Laboratory for training as an examiner, where he evaluated evidence and provided on-site field support in domestic cases, as well as abroad. He also designed and taught basic- and management-level forensic courses at the FBI Academy, Quantico, Virginia, 1982-1988. Jack retired from the FBI as Chief of the Firearms/Toolmarks Unit in 1994, and continues to consult in forensic firearm cases and in training design and delivery.



Bullets and shotshell projectiles may be the only firearms-related evidence recovered from a crime scene or from the body of a shooting victim. Even when no firearm is recovered, significant information may still be obtained from examination of the projectile. This module addresses the evidentiary potential of bullets, pellets, shotgun slugs, or wadding recovered from a crime scene or the body of a victim.



At the conclusion of this module the student should be able to do the following:

  • Discuss the preliminary considerations that must be addressed prior to performing examinations of fired bullets
  • Describe the physical features of fired and unfired bullets resulting from design specifications and the manufacturing process
  • Explain the use of bullet physical features in searching a standard ammunition file (SAF)
  • Describe the concepts related to general rifling characteristics, including:
    • What they are and where they are located
    • Defining the dimensions to be measured
    • Techniques for taking measurements
    • Equipment options for taking measurements
    • The FBI General Rifling Characteristics File
    • Calculation of caliber from damaged bullets
    • The evidentiary potential of fired bullets
  • Describe the potential challenges in the determination of general rifling characteristics
  • Describe the types of equipment necessary for performing examinations of fired bullets
  • Provide an overview of the contents of worksheets used in the examination of fired bullets
  • List the categories of possible conclusions in regard to fired bullets
  • Describe the format and administrative contents of a formal report in regard to fired bullets
  • Outline the formats for reporting technical results and conclusions in formal reports
  • Discuss the forensic potential and probative value of fired shotshell wadding, pellets, buckshot, slugs, and buffer
  • Describe the examination protocol for shotshell wadding, pellets, buckshot, slugs, and buffer
  • Articulate the contents of a typical worksheet for fired wadding, pellets, buckshot, slugs, and buffer
  • Discuss typical formats and content for reporting of results of the examination of shotshell wadding, pellets, buckshot, slugs, and buffer
  • Describe the references available in regard to ammunition and bullets in the form of:
    • Printed materials
    • Physical files
    • Reference data in digital form
    • Internet accessed information
  • Describe the recommendations of the Association of Firearm and Tool Mark Examiners in regard to the minimum requirements for the contents of laboratory bench notes for the examination of fired bullets


AFTE Knowledge and Ability Factors

14. Knowledge of how to properly document evidence and analytical results (through notes, sketches, photography, reports, etc.)
15. Knowledge of the techniques and procedures used to properly mark evidence (when appropriate)
26.* Knowledge of definitions of class, subclass, and individual characteristics and the differences between them
27.* Knowledge of the sources of class, subclass, and individual characteristics
41. How and when to use various cleaning solutions
42. Knowledge of how and when to use pulled-bullet/cartridge exemplar files (SAF)
74. Knowledge of machining and finishing processes of tools, guns, barrels, breech faces, extractors, ejectors, firing pins, and silencers (with emphasis on working surfaces and edges) and their effect on individuality
86. Knowledge of projectiles: design (ogive shape, base shape, cannelure types, forming processes); construction and composition (lead alloy compositions, jacketing materials and styles, etc.)
97. Knowledge of proper ammunition selection (for microscopic comparison and for duplication of patterns of GSR)
116.* Knowledge of the interactive nature of the tool/toolmark process and the transference of class, subclass, and individual characteristics
19. Ability to understand and interpret technical data output from laboratory instruments
21. Ability to recognize discrepancies or inconsistencies in analytical findings and determine their cause and significance
22. Ability to recognize utility and limitations of reference collection/database programs
23. Ability to recognize the limitations of tests and interpretations
30. Ability to recognize the effect that firearms and ammunition manufacturing processes, the design of firearms, and design of firearms accessories have on markings imparted to bullets and casings and to interpret them accordingly
31.* Ability to recognize different manufacturing methods and, based upon this, to properly interpret potential for class, subclass, and individual characteristics
33. Ability to recognize and discriminate common rifling profiles (GRC database or file)
39. Ability to recognize, compare and identify various ammunition types and components
43. Ability to recognize reloaded or handloaded ammunition
44. Ability to compare ammunition components on the basis of design characteristics or features
46. Ability to recognize: (1) those attributes or characteristics of a particular firearm design which are reflected in the fired projectiles and fired cartridge cases; and (2) nonfirearm caused toolmarks on ammunition components
49.* Ability to recognize, determine the source of, and differentiate between class, subclass, and individual characteristics on bullets, cartridges, cartridge cases, and in nonfirearm related toolmarks
50. Ability to make comparisons between evidence and reference cartridges and recovered cartridge components
54. Ability to recognize commercially reloaded or handloaded ammunition components from their markings and characteristics
55. Ability to identify reloaded ammunition as having been assembled by the same manufacturer and/or containing the same brand of components
56. Ability to recognize the evidentiary value of reloaded ammunition
71. Ability to make determinations in toolmark comparisons (both firearm and nonfirearm toolmarks) regarding identifications, exclusions, and inconclusives
72. Ability to recognize patterns (profiles, etc.) produced by various tool working surfaces
73. Ability to recognize sources of class, subclass, and individual characteristics on any given tool
74. Ability to recognize toolmarks as being class, subclass, or individual in nature
* Module 9 includes information on class, subclass, and individual characteristics in regard to cartridge cases; Module 10 includes Class characteristic information on fired and unfired bullets; and Module 11 includes information on subclass and individual characteristics in regards to fired bullets


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