Firearms and Toolmarks
Markings studied as part of firearm analysts are yet another example of Locard’s principle. The contact between two metal surfaces leaves markings as evidence of the contact. The markings are another type of pattern evidence that are evaluated by successive classification techniques. Forensic analysts in this field may also be involved in related tasks, such as evaluating the safety and operability of a gun, measuring its overall length and that of the barrel, estimating distances from weapons to targets, reconstructing shooting events, and restoring serial numbers that have been scratched or scraped off metal surfaces. We touch on all these topics in the chapter.
Learning Objectives
16.1 Describe the basic operating principles of modern firearms and ammunition
16.2 Understand the mechanism by which markings are imparted to surfaces
16.3 Understand the application of the comparison microscope in firearms and tool mark analysis
16.4 Recognize the basic steps for characterizing and classifying marks
16.7 Describe the principles behind, and steps used in distance estimation and serial number restoration
