NCJ Number
51790
Journal
Journal of Forensic Sciences Volume: 23 Issue: 4 Dated: (OCTOBER 1978) Pages: 687-692
Date Published
1978
Length
6 pages
Annotation
THE PRESENCE OF LEAD RESIDUE ON THE EXIT SIDE OF A BULLET TARGET IS EXAMINED ALONG WITH DIFFERENCES BETWEEN POWDER PATTERNS AND LEAD RESIDUE. EFFECTS OF VARYING DISTANCES, CALIBERS, AND BULLET COMPOSITIONS ARE CONSIDERED.
Abstract
A CASE INVOLVING A RIFLE USED TO FIRE THROUGH A WINDOW AND SHADE WAS BEING INVESTIGATED WHEN AN OFFICER NOTICED THAT A GRAY-BLACK RESIDUE SURROUNDED THE BULLET HOLE ON THE EXIT SIDE OF THE TARGET MATERIAL. THE RESIDUE LOOKED LIKE THE GUNSHOT POWDER WHICH APPEARS ON THE EXIT SIDE OF THE TARGET, EXCEPT THAT FOR THE PRESENCE OF A CLEAR AREA SURROUNDING THE HOLE. A LABORATORY EXAMINATION OF THE MATERIAL WAS CONDUCTED AND A SETUP WAS DEVISED FOR NUMEROUS TEST FIRINGS AT VARIOUS DISTANCES WITH DIFFERENT TARGET MATERIALS AND BACKUPS. THE REVERSE SIDE OF THE TARGET SHEETS WAS EXAMINED AFTER FIRINGS, AND ANY RESIDUE WAS SUBMITTED TO VARIOUS ANALYSES. THE RESIDUE ON THE EXIT SIDE OF THE TARGET MATERIALS WAS DETERMINED TO BE LEAD, WITH NO OTHER ELEMENTS DETECTED BY ENERGY DISPERSIVE X-RAY ANALYSIS. THE RESIDUE WAS CAUSED BY THE MELTING OF LEAD ALLOY DUE TO HEAT FROM THE CARTRIDGE EXPLOSION AND FRICTION. THE DISTANCE OF THE WEAPON TO THE TARGET WAS NOT ESSENTIAL TO THE DEPOSIT OR SIZE OF THE RESIDUE PATTERN, UNLESS IT WAS GREATER THAN 30 FEET; THE VARYING DISTANCE BETWEEN THE TARGET AND BACKUP HAD THE GREATEST EFFECT ON THE PATTERN. SMALLER CALIBER AND SLOWER VELOCITY BULLETS LEFT LIGHTER DENSITY PATTERNS. LEAD RESIDUES WERE CHARACTERIZED BY HALO-LIKE DEPOSITS ENCIRCLING A A CLEAR AREA ADJACENT TO A BULLET HOLE. EQUIPMENT DEVISED FOR THE TESTS IS DESCRIBED AND PHOTOGRAPHS OF THE PATTERNS ARE PRESENTED. BIBLIOGRAPHICAL REFERENCES ARE PROVIDED. (DAG)