Firearms, the Law and Forensic Ballistics Firearms, the Law and Forensic Ballistics T.A.WARLOW UK Taylor & Francis Ltd, 1 Gunpowder Square, London EC4A 3DE USA Taylor & Francis Inc., 1900 Frost Road, Suite 101, Bristol, PA 19007 This edition published in the Taylor & Francis e-Library, 2003. Copyright © Taylor & Francis Ltd 1996 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, electrostatic, magnetic tape, mechanical, photocopying, recording or otherwise, without the prior permission of the copyright owner. British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library ISBN 0-203-48305-7 Master e-book ISBN ISBN 0-203-79129-0 (Adobe eReader Format) ISBN 0-7484-0432-5 (cased) Library of Congress Cataloging Publication Data are available Some of the photographic material was provided courtesy of the Forensic Science Service and CBDE Porton Down. Cover design by Youngs Design in Production Contents Preface ix Foreword xi Author’s Note xiii 1 The Beginnings 1 1.1 Blow-Pipes, Air and Gas Guns 3 1.2 Percussion Ignition 4 1.3Modern Rim-Fire and Centre-Fire Cartridges 5 1.4 Smokeless Powders and Modern Arms 7 Further Reading 8 2 Firearms Legislation and the Definition of a Firearm 11 2.1 History of Weapons Legislation in Britain 11 2.2 Legislation and Gun Control 12 2.3Firearms and Crime 17 2.4 The Firearms Consultative Committee 22 2.5 The European Weapons Directive 24 2.6 Legislation in the US 25 Further Reading 27 3Marks and Microscopy—The Emergence of a New Science 33 3.1 The Pioneers 33 3.2 Experts and Charlatans—The American Experience 34 3.3 Court Battles—The English Experience 35 Further Reading 37 4 Mechanisms and Design Aspects of Firearms 39 4.1 Hinged Barrel Designs 39 4.2 Hammer Shotguns 39 4.3Accidental Discharge 40 4.4 Repeating Arms 40 v Contents 4.5 Magazine Systems 42 4.6 Bolt-Action Weapons 44 4.7 Lever-Action Rifles 44 4.8 The Revolver 44 4.9 Accident by Design? 45 4.10 Safety Catches and Internal Safeguards 46 4.11 Decocking Devices and Alternative Designs 48 4.12 Hazard Indicator Devices 49 4.13Bolt-Action Rifle Safety Catches 49 4.14 Trigger Pulls 49 4.15 Blow-Back and Locked Breech Designs 51 4.16 Gas Operated Arms 53 4.17 Gas and Air Weapon Designs 54 4.18 Crossbows 55 Further Reading 56 5 Internal Ballistics 65 5.1 Basic Principles 65 5.2 The Efficiency of Energy Transfer 65 5.3Powders and Pressures 67 5.4 Control of Powder Burning Rates 68 5.5 Drachms and Drams 69 5.6 The Residues of Combustion 69 5.7 Primer Formulations 70 5.8 Gunshot Residue Analysis 71 5.9 The Transfer of Marks to Missiles and Cartridge Cases 72 5.10 The Microscopy of Air Weapon Missiles 74 5.11 Recoil and Barrel Flip 74 5.12 Choke Boring of Shotguns 76 5.13Gauges and Bore Sizes 77 Further Reading 77 6 External Ballistics and Cartridge Loadings 81 6.1 Basic Principles 81 6.2 Bullet Stability and Instability 81 6.3The Bullet’s Flight 82 6.4 Bullet Shapes and Sectional Densities 83 6.5 External Ballistics and their Calculation 83 6.6 Accuracy 85 6.7 Fin and Aerodynamic Stabilisation 87 6.8 The Question of Range 88 6.9 The Spent Bullet Myth 89 6.10 Secondary Ejecta 89 6.11 The Behaviour of Shotgun Wadding 90 6.12 Sabot Loadings 91 6.13Choke Boring—Shotgun Pellet Spread and Velocity 91 6.14 Pellet Deformation within the Bore 93 6.15 Choke Operation 94 vi Contents 6.16 Soft and Hard Shot—Shotgun Pellet Ballistics 95 6.17 Steel Shot Loadings 95 6.18 Alternative Non-Lead Materials 97 6.19 Pellet Sizes and Weights 97 6.20 The Propensity for Ricochet 99 Further Reading 100 7 Terminal/Wound Ballistics and Distance of Firing 109 7.1 Incidence of Ricochet 110 7.2 Consequences of Impact and Penetration 111 7.3Armour-Piercing Ammunition 112 7.4 Explosive Anti-Armour Munitions 113 7.5 Shotgun Missile Injuries 114 7.6 Expanding Bullets 116 7.7 High-Velocity Wound Effects 119 7.8 Range Determination of Single Missile Injuries 123 Further Reading 126 8 The Scene of the Shooting Incident 139 8.1 The On-Call Rota System 139 8.2 Arrival at the Scene 139 8.3Scene Examination 140 8.4 Initial Examination of the Body 145 8.5 X-Ray Examination 147 8.6 The First Samples and Observations 147 8.7 The Wound Sites 148 8.8 Arrow and Crossbow Bolt Injuries 150 8.9 Blank Operated Tool and Humane Killer Injuries 151 8.10 The Wound Track 152 8.11 Examination of PM Exhibits Back at the Laboratory 157 Further Reading 158 9 Examination of Exhibits at the Laboratory 173 9.1 Initial Examination of Firearms 173 9.2 Trigger Pulls and Mechanical Tests 176 9.3Firing Range Tests 179 9.4 Incomplete, Defective and Converted Arms 185 9.5 Recovery of Serial Marks 186 9.6 Examination of Ammunition 188 9.7 Tear-Gas and Irritant Loadings 190 9.8 Electric Shock Devices and Stun Guns 191 9.9 Recovered Cartridge Cases, Bullets, Pellets and Wadding 191 9.10 Examination of Bullet- or Pellet-Damaged Items 195 9.11 Comparison Microscopy 195 9.12 The Electron Microscope 197 9.13Analysis of Firearms Discharge Residues 198 Further Reading 200 vii Contents 10 Presentation of Evidence to the Courts 223 10.1 The Prosecution Witness 224 10.2 The Defence Expert 231 Further Reading 233 11 Proof Marks and the Proof of Firearms 235 11.1 UK Proof Markings 241 11.2 Austrian Proof Marks 245 11.3Belgian Proof Marks 246 11.4 Chilean Proof Marks 249 11.5 Czech Republic Proof Marks 250 11.6 French Proof Marks 250 11.7 German Proof Marks 252 11.8 Finnish Proof Marks 254 11.9 Hungarian Proof Marks 255 11.10 Italian Proof Marks 255 11.11 Spanish Proof Marks 256 11.12 Yugoslav Proof Marks 259 11.13The Russian Federation 259 11.14 Choke Markings 260 11.15 Irish Proof Marks 264 11.16 Swedish Proof Marks 264 11.17 Swiss Proof Marks 265 Further Reading 265 Appendix 1Useful Data 267 Appendix 2 German Ordnance Codes used between 1938 and 1945 273 Index 293 viii Preface From my youth to middle age I have been fascinated by firearms and their application. Over the years I have tried, and in some instances have mastered, just about every type of firearm and shooting discipline. Even today I am still filled with awe by the accuracy of a fine rifle and its ability to deliver a compact package containing so much destructive force to a distant target. My own rifle, which I use for target shooting and deer stalking, frequently produces subminute of angle groups at one hundred yards. (Somewhat less than one inch in measurement between the centres of the most distant bullet strikes in the group.) When one considers that such feats are achieved with what is in reality a heat engine of Victorian design the results seem even more remarkable. One day many years ago I decided to extend my interest further by accepting an offer of employment from the Home Office at the National Firearms Laboratory of the Forensic Science Service at a laboratory location in the centre of Nottingham; at a later date the unit was moved to its present location in Huntingdon, Cambridgeshire. Although familiar with the sight of death in the field, it was there that I became truly conversant with the darker side of the application of firearms. Nevertheless, even when assisting with a post-mortem examination of a luckless victim I was still able to lock on to the firearms aspects of the investigation. Aspects of range, line of fire, the weapon type and calibre, the brand of ammunition used and nature of loading, the likely make and model of firearm used in the shooting and whether it had been used in a previous shooting incident, and finally establishing a positive association at some later date with a recovered weapon. Finally, of course there comes the presentation of one’s evidence to the court. In order to consider oneself to be an expert witness in such a specialised field it is necessary to try to understand all aspects of the subject, rather than to lock on to one small discipline. I have decided therefore to start this book with a short chapter on the development of arms and ammunition from the fourteenth century to the present day in order that a balanced understanding of firearms and ammunition can be acquired. I hope also that this chapter will also be of general interest to all those who have a genuine interest in firearms, as although wide-reaching, it is set out in a relatively condensed form which will not be found elsewhere. This is followed by a chapter concerned with firearms law around the world with particular emphasis upon the ix