Forensic Ballistics in Court

Brian J. Heard, Formerly of the Ballistics and Firearms Identification Bureau for the Royal Hong Kong Police.

• About the Author xiiiIntroduction xvAbout the companion website xix1.0 Firearms History 11.0.1 Introduction 11.0.2 The flintlock 11.0.3 The percussion system 31.0.4 The pinfire system 31.0.5 The rimfire system 41.0.6 The Dreyse needle fire system 41.0.7 The centre fire system 51.0.8 The revolver 51.0.9 The self-loading pistol 6Further reading 82.0 Weapon Types and Their Operation 92.0.1 Introduction 92.0.2 Handguns 92.0.3 Rifles 132.0.4 Shotguns 142.0.5 Combination weapons 152.0.6 Sub-machine guns 152.0.7 Assault rifles 162.0.8 Machine guns and heavy machine guns 162.0.9 Muzzle attachments 162.0.10 Important parts of a weapons mechanism 192.0.11 Bent and sear 202.0.12 Other important parts of a revolver mechanism 222.0.13 Hand and ratchet 23Further reading 242.1 Gas and Air Powered Weapons 252.1.1 Introduction 252.1.2 Weapon types 252.1.3 Ammunition 282.1.4 Considerations 30Further reading 312.2 Rifling Types and Their Identification 332.2.1 Introduction 332.2.2 Basics 342.2.3 Class characteristics 372.2.4 General introduction to rifling 38Additional reading 422.3 Home-made, Improvised and Converted Firearms 432.3.1 Introduction 432.3.2 Improvised firearms 432.3.3 Converting air weapons 442.3.4 Home-made and converted toys and replica weapons 452.3.5 Home-made ammunition 48Further reading 502.4 Antique Weapons 512.4.1 Introduction 512.4.2 Background 512.4.3 Defining ‘antique’ 523.0 Proof Marks 553.0.1 Introduction 553.0.2 Proof marks 553.0.3 Types of proof 563.0.4 Proof marks and the examiner 563.0.5 Examples of proof marks 56Further reading 614.0 A Brief History of Ammunition 634.0.1 Introduction 634.0.2 Basics 63Further reading 664.1 Ammunition Components 674.1.1 Introduction 674.1.2 Basics 674.1.3 Ammunition types 684.1.4 Primer cap types 694.1.5 Cartridge cases 704.1.6 Shotgun ammunition 73Further reading 794.2 Bullet Types 814.2.1 Introduction 814.2.2 Basics 814.2.3 Bullet materials 814.2.4 Other bullet types 834.2.5 Bullet nose configuration 834.2.6 Bullet base configuration 854.2.7 Bullet lubrication 85Further reading 864.3 Headstamps and Other Identifying Features on Ammunition 874.3.1 Introduction 874.3.2 Basics 884.3.3 Clandestine ammunition 894.3.4 Colour coding of ammunition 90Further reading 914.4 Non-toxic and Frangible Bullets 934.4.1 Introduction 934.4.2 Elimination of lead in ammunition 934.4.3 Materials used in non-toxic ammunition 944.4.4 The current situation 94Further reading 964.5 Non-toxic Shot 974.5.1 Introduction 974.5.2 Materials used in non-toxic shotgun ammunition 97Suggested further reading 1004.6 A Brief History of Propellants 1014.6.1 Introduction 1014.6.2 Basics 1014.6.3 Black powder 1024.6.4 Nitro propellants 1044.6.5 Dating of ammunition 1074.6.6 Reduced loads for target shooting 107Further reading 1084.7 Priming Compounds 1094.7.1 Introduction 1094.7.2 Basics 1104.7.3 A short history of priming compounds 1104.7.4 Manufacture 1134.7.5 Accidental discharge of primers 113Further reading 1145.0 An Introduction to Ballistics 1155.0.1 Introduction 1155.0.2 Basics 1155.0.3 Background 115Further reading 1165.1 Internal Ballistics 1175.1.1 Introduction 1175.1.2 Basics 1175.1.3 Recoil 1185.1.4 Barrel pressure 120Further reading 1215.2 External Ballistics 1235.2.1 Introduction 1235.2.2 Basics 1245.2.3 Maximum range of missiles 1265.2.4 Maximum altitude that a bullet will attain 1305.2.5 Terminal velocity 1315.2.6 Use of sight to compensate for bullet drop 1325.2.7 Other influencing factors 1325.2.8 Muzzle energy 1345.2.9 Momentum 135Further reading 1355.3 Terminal Ballistics 1375.3.1 Introduction 1375.3.2 Basics 1375.3.3 General wound ballistic concepts 1395.3.4 Other factors influencing the wounding capabilities of a missile 1445.3.5 Bullet performance and ‘wounding capabilities’ 1455.3.6 Relative stopping power (RSP) 1475.3.7 Bullet resistant vests (BRV) 149Further reading 1526.0 A Brief History of Forensic Firearms Identification 1536.0.1 Introduction 1536.0.2 Early cases involving bullet identification 1546.0.3 Use of photomicrographs 1546.0.4 Identification of weapon from breech face markings 1556.0.5 Early use of comparison microscope 1556.0.6 Introduction of the binocular comparison microscope 1566.0.7 Improvements in illumination 1576.0.8 Photography of stria 1576.0.9 Modern technology for stria comparison 157Suggested further reading 1607.0 Basic Concepts of Striation Matching 1617.0.1 Introduction 1617.0.2 Basics 1627.0.3 Identification of weapon type 1647.0.4 Individual characteristics on cartridge cases 1657.0.5 Formation of stria 1667.0.6 Problematical areas 167Further reading 1727.1 Basic Concepts in Comparison Microscopy 1737.1.1 Introduction 1737.1.2 Basic methodology and background to stria comparisons 1747.1.3 Lighting used for comparison microscopy 1757.1.4 The concept of consecutive matching stria 1777.1.5 Obtaining control samples 1777.1.6 Manufacturing marks on ammunition 1787.1.7 Recovery methods for fired bullets 1787.1.8 Conclusion 180Further reading 1817.2 The Concept of Consecutive Matching Stria 1837.2.1 Introduction 1837.2.2 Basics 1837.2.3 Arguments for and against the concept of stria comparisons 186Further reading 1877.3 A Statistical Model to Illustrate the Concept of Individuality in Striation Matches 1897.3.1 Introduction 1897.3.2 Basics 1897.3.3 Stria individuality 1907.3.4 Philosophy 191References 1938.0 Accidental Discharge 1958.0.1 Introduction 1958.0.2 Basics 1978.0.3 Trigger mechanisms 1978.0.4 Reasons for an accidental discharge 1988.0.5 Negligent discharges 203Further reading 2049.0 Identification of Calibre from the Bullet Entry Hole 2059.0.1 Introduction 2059.0.2 Basics 2069.0.3 Determination of bullet type 207Further reading 20810.0 Ricochet Analysis 20910.0.1 Introduction 20910.0.2 Basics 20910.0.3 Variables influencing the liability of a missile to ricochet 210Further reading 21311.0 Bullet Penetration and Trajectory through Glass 21511.0.1 Introduction 21511.0.2 Glass types and glass substitutes 21511.0.3 Deviation of missile after penetrating glass 21711.0.4 Penetration of normal window glass 21711.0.5 Penetration of laminated and bullet-resistant glass 21811.0.6 Penetration of tempered or toughened glass 21911.0.7 Determination of bullet type from the entry hole 22011.0.8 Deflection of bullet by glass 221Further reading and references 22312.0 Range of Firing Estimations and Bullet Hole Examinations 22512.0.1 Introduction 22512.0.2 Basics 22512.0.3 Range of firing estimations for pistols and rifles 22712.0.4 Extended range of fire estimations 23012.0.5 Range of firing estimations on badly decomposed bodies 23112.0.6 Bullet wipe marks 23112.1 Chemical Tests for Range of Fire Estimations and Bullet Entry/Exit Hole Identification 23512.1.1 Introduction 23512.1.2 Chemical tests for range of firing estimations 23512.1.3 Range of firing estimations on heavily bloodstained garments 23712.1.4 Range of firing estimations for non-toxic non-lead primers 238Further reading 23912.2 Range of Fire Estimations for Shotguns 24112.2.1 Introduction 24112.2.2 Basics 24212.2.3 Shotgun cartridges fired in revolvers 246Suggested further reading 24713.0 The Use of X-ray Photography for Projectile Identification 24913.0.1 Introduction 24913.0.2 Estimation of calibre from X-ray photographs 250Further reading 25414.0 Gunshot Residue Examination 25514.0.1 Introduction 25514.0.2 Basics 25614.0.3 Identification of GSR Particles 25714.0.4 The use of the scanning electron microscope (SEM) with energy dispersive X-Ray analysis (EDX) for the detection and analysis of GSR particles 25914.0.5 Sample collection 26014.0.6 GSR retention 26314.0.7 Interpretation of results 26414.0.8 Identification of type of ammunition and country or origin from GSR composition 26514.0.9 Environmental contaminants 26714.0.10 Extending the period over which GSR particles can be recovered 26914.0.11 General considerations to be made when examining GSR analysis results 27214.0.12 Discussion 274References 27515.0 Gun Handling Tests 27715.0.1 Introduction 27715.0.2 History 27815.0.3 Methodology for the use of Ferrozine 279Further reading 28316.0 Laser-etched Serial Numbers and Bar Codes 28516.0.1 Introduction 28516.0.2 Laser-etched serial numbers 28516.0.3 Bar codes 28616.0.4 Conclusion 287Further reading 28717.0 Classification of Firearms-related Death 28917.0.1 Introduction 28917.0.2 Basics 28917.0.3 Multiple shot suicides 290References and further reading 29318.0 Practical Considerations in a Firearms Case from a Legal Point of View 29518.0.1 Introduction 29518.0.2 Key questions 29618.0.3 Legal challenges to forensic firearms evidence in the USA 29818.0.4 Conclusion 300Further reading and references 30019.0 Qualifying the Expert and Cross-examination Questions 30119.0.1 Definition 30119.0.2 Introduction 30119.0.3 Qualifying the expert 30219.0.4 General background questions 30319.0.5 Comparison microscopy 30319.0.6 Gunshot residue 30619.0.7 Ferrozine test 308Further reading 30820.0 Chain of Custody 30920.0.1 Introduction 30920.0.2 Basics 30920.0.3 Process 31020.0.4 In court 310Further reading 311Appendix 1 Standard of Review: ‘Daubert Trilogy’ 313Appendix 2 Commercial and General Abbreviations for Bullet Configurations 317Appendix 3 Some of the More Common Trade Names 323Appendix 4 Important dates in the History of Firearms from 1247 335Appendix 5 Dates for the Introduction of Various Cartridges by Calibre 341Appendix 6 Some Trademarks Found on Guns 345Appendix 7 General Firearms Values Conversion Table 349Appendix 8 Hearing Loss 351Appendix 9 A List of Handgun Cartridges 355Appendix 10 A List of Rifle Cartridges 357Appendix 11 Air Weapon Legislation 361Index 367