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NCJRS Abstract

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NCJ Number: 49400 Find in a Library
Title: WHAT GUN IS THAT? FIREARMS IDENTIFICATION FOR POLICE OFFICERS (FROM LAW ENFORCEMENT BIBLE, 1978, BY ROBERT A SCANLON - SEE NCJ-49390)
Author(s): P DRAGAN
Corporate Author: Stoeger Publishing Co
United States of America
Date Published: 1978
Page Count: 8
Sponsoring Agency: Stoeger Publishing Co
South Hackensack, NJ 07606
Format: Document
Language: English
Country: United States of America
Annotation: AN INTRODUCTION TO FIREARMS IDENTIFICATION IS PRESENTED. TOPICS COVERED INCLUDE CLASS CHARACTERISTICS OF BULLETS, FIREARM IDENTIFIERS, TEST FIRING, THE IDENTIFICATION PROCESS, AND THE TYPES OF INFORMATION DETERMINABLE.
Abstract: BECAUSE OF STANDARDIZATION A NUMBER OF CLASS CHARACTERISTICS OF BULLETS CAN BE USED TO IDENTIFY THE WEAPON FROM WHICH A BULLET WAS FIRED. THESE INCLUDE: THE CALIBER, THE LANDS AND GROOVES RESULTING FROM PASSAGE THROUGH RIFLING OF THE BARREL WHICH MAY VARY BETWEEN 2 AND 22, THE DIRECTION OF THE TWIST OF THE LANDS AND GROOVES, THE WIDTH OF THE LAND AND GROOVES, THE DEPTH OF THE GROOVES, AND THE WEIGHT OF THE BULLET (USUALLY NOT IMPORTANT TO IDENTIFICATION). ONCE THESE CHARACTERISTICS ARE IDENTIFIED, IT IS OFTEN POSSIBLE TO TELL WHAT MAKE OR TYPE OF WEAPON FIRED THE BULLET. IDENTIFICATION OF CHARACTERISTICS RESULTING FROM WEAR, REPLACED PARTS, OR INTENTIONAL DEFACING OF PARTS MAY AID IN DETERMINING THE SPECIFIC WEAPON WHICH FIRED THE BULLET. BESIDES THE MAKE, MODEL, AND SERIAL NUMBER, BARREL LENGTH CAN BE MEASURED, THE NUMBER OF SHOTS AND CALIBER CAN BE DETERMINED, AND THE FINISH AND OTHER SPECIFIC CHARACTERISTICS OF A PARTICULAR WEAPON MAY BE DESCRIBED. ONCE THE WEAPON HAS BEEN FULLY DESCRIBED, TEST FIRING ASCERTAINS THAT THE WEAPON IS FUNCTIONAL AND PROVIDES THE EXAMINER WITH SPENT BULLETS AND CARTRIDGES FOR COMPARISON. THE BULLET MAY BE FIRED INTO A 6 BY 1 FOOT BOX FILLED WITH COTTON WASTE MATERIAL OR INTO A WATER TANK. THE WATER TANK METHOD PERMITS RETRIEVAL OF SAMPLES FREE FROM DEBRIS AND WITHOUT DESTROYING MICROSCOPIC MARKINGS WHICH MAY BE VITAL TO IDENTIFICATION. A FORENSIC COMPARISON MICROSCOPE, CONSISTING OF A SINGLE EYEPIECE WITH TWO OBJECT STAGES PERMITS THE OBSERVER TO VIEW TWO SAMPLES SIMULTANEOUSLY. BY EXAMINING THE EVIDENCE IT IS POSSIBLE TO DETERMINE: THE MAKE OR TYPE OF WEAPON FROM WHICH A BULLET OR CARTRIDGE CASE/SHOT SHELL WAS FIRED; WHETHER THE MARKINGS ON THE BULLET, CASE, OR SHELL CAN BE IDENTIFIED SUFFICIENTLY WITH A PARTICULAR GUN IN QUESTION; WHETHER A PARTICULAR WEAPON DID IN FACT FIRE THE BULLET, SHELL OR CARTRIDGE; WHETHER SEVERAL BULLETS, SHELLS OR CARTRIDGES WERE FIRED FROM THE SAME WEAPON OR FROM TWO OR MORE WEAPONS; WHETHER A WEAPON IS FUNCTIONAL AND WHETHER ITS OPERATION IS NORMAL OR ABNORMAL; AND, BY USING A SIMILAR WEAPON AND AMMUNITION, DETERMINE THE DISTANCE OF THE SHOT. THE MARKING OF WEAPONS OR LIVE/SPENT AMMUNITION TO PERMIT IDENTIFICATION WITHOUT OBSCURING RIFLED PORTIONS IS IMPORTANT IN MAKING POSITIVE IDENTIFICATION AND PRESERVING THE CHAIN OF EVIDENCE. (JAP)
Index Term(s): Ammunition; Ballistics; Evidence identification; Firearms identification; Techniques
To cite this abstract, use the following link:
http://www.ncjrs.gov/App/publications/abstract.aspx?ID=49400

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