EVALUATION OF SEM (SCANNING ELECTRON MICROSCOPE) POTENTIAL IN THE EXAMINATION OF SHOTGUN AND RIFLE FIRING PIN IMPRESSIONS

• NCJ Number: 16712
• Journal: Journal of Forensic Sciences Volume: 19 Issue: 3 Dated: (JULY 1974) Pages: 441-447
• Author(s): C A GROVE; G JUDD; R HORN
• Date Published: 1974
• Length: 7 pages
• Corporate Author: American Soc for Testing and Materials
• Publication Format: Article
• Language: English
• Country: United States of America
• Note: *This document is currently unavailable from NCJRS. PAPER PRESENTED AT THE 25TH ANNUAL MEETING OF THE AMERICAN ACADEMY OF FORENSIC SCIENCES, LAS VEGAS, NEVADA, FEB 22, 1973

Annotation

THE FIRING PIN IMPRESSIONS FROM A TOTAL OF TWELVE AUTOEJECTING SHOTGUNS AND RIFLES WERE EXAMINED BY THE SCANNING ELECTRON MICROSCOPE (SEM).

Abstract

THE FIRST, SECOND, TENTH, AND IN SOME CASES THE FIFTIETH FIRING PIN IMPRESSIONS WERE EXAMINED. THE SEM IMAGES OF THE FIRING PIN IMPRESSIONS PROVED TO REVEAL CLEARLY ALL OF THE SURFACE DETAIL IN THE IMPRESSION. FIFTY PERCENT OF THE SHOTGUN IMPRESSIONS AND 75 PERCENT OF THE RIFLE IMPRESSIONS COULD BE POSITIVELY IDENTIFIED ON THE BASIS OF FOUR OR MORE INDIVIDUAL CHARACTERISTICS, IN ADDITION TO THE SIMILARITY OF CLASS CHARACTERISTICS. THE EFFECT OF PREEXISTING PRIMER MARKS ON THE FIRING PIN IMPRESSIONS WAS INVESTIGATED BY EXAMINING SEVERAL .25 CALIBER PRIMERS, BEFORE AND AFTER FIRING IN THE SEM. IT WAS FOUND THAT THE PREEXISTING MARKS DID NOT CAUSE ARTIFACTS ON ANY OF THE FIRING PIN IMPRESSIONS. (AUTHOR ABSTRACT)