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Firearms Examiner Training

Module 04: Modern Firearms Manufacture

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Illustration of a gun being fired with a photo of a bullet on top
Select image components courtesy of FirearmsID.com (see reuse policy).

 

Author: J. Allan Jones
Photo of J. Allan Jones
National Institute of Justice (NIJ) (see reuse policy).
J. Allan Jones obtained a Bachelor of Science degree (1969) from Southern Methodist University and continued graduate studies there until 1971, when he joined the Dallas County (Texas) Institute of Forensic Sciences Crime Laboratory as a firearm examiner. Mr. Jones worked in that capacity until 1987, when he moved to Lewiston, Idaho, as the manager of technical publications for CCI Ammunition and Speer Bullets. He directed ballistics research for and authored Speer Reloading Manual, numbers 12, 13, and 14. Mr. Jones retired from CCI/Speer in 2007.

Introduction

This module primarily covers the fabrication of metal components of firearms using common manufacturing technologies. Wooden, plastic, or composite stocks and grips are not discussed in this module.

Firearms manufacturing technologies are important to the firearm examiner because this is where class and individual characteristics originate. Knowledge of the manufacturing materials used provides practical information about the functional characteristics and durability of the firearm.

Objectives

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

  • Describe traditional and current metal-forming processes, methods, and materials
  • Describe the methods used for making barrels
  • Define the rifling processes
  • Describe the effect rifling has on bullets
  • Define the contouring and crowning process
  • Identify the main components of a firearm
  • Identify the parts of a firearm that can produce identifiable marks for firearms identification
  • Describe the firearm finishing and testing process

AFTE Knowledge and Ability Factors

73. Knowledge of the historical development of firearms design
74. Knowledge of machining and finishing processes of tools, guns, barrels, breechfaces, extractors, ejectors, firing pins, and silencers (with emphasis on working surfaces and edges) and their effect on individuality. (Note: silencer marks are noted in module 11.)
80. Knowledge of sources of information regarding identification markings and serial numbering systems in firearms (including locations of serial numbers, part/assembly numbers, proof marks on firearms, and the locations of hidden numbers)
98. Knowledge of internal ballistics: ignition, pressure, function of chamber design, chamber and cartridge dimensions, headspace considerations
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
47. Ability to determine the source and uniqueness of various striated and/or static marks on bullets and cartridges

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