Shot Range Determination

ISBN-13: 9783642767234 / Angielski / Miękka / 2011 / 105 str.

Karl Sellier

Opis

The range at which a weapon has been fired is an important measurement for the reconstruction of firearms offenses (murder, suicide, accident). All changes caused by a shot and which vary according to the distance from the weapon are suitable in principle for determining this distance. However, some procedures are very elegant in theory but hardly applicable in practice. The constructions of ammunition and the sequence of events during a shot are dealt with first as this knowledge forms a basis for understanding the various methods. The individual zones (classes) of firing distances (contact shot, intermediate shot, distance shot) are described. In this connection, the morphological methods for determining the firing distance are discussed. From the shape and size of the powder residue distribution (soot stains, powder tattooing) and with the knowledge of the weapon and ammunition, the distance from the target can be elucidated. In this chapter, the methods of making an invisible distribution visible are also dealt with. In order to determine the range of the shot from the appearance of the wound no complicated apparatus is necessary. One can judge with the naked eye. These procedures have a great advantage over the methods discussed in the following chapter in that they give stronger proof. They are more vivid and convincing for the uninitiated (judge or jury) than abstract measurements obtained by scientific devices.

Spis treści

1 Introduction.- 2 General Section.- 2.1 Ammunitions.- 2.1.1 Normal Ammunition.- 2.1.1.1 Primer Ingredients.- 2.1.1.2 Powder.- 2.1.1.3 Bullets and Cases.- 2.1.2 Shot Shells (Shotgun Cartridges).- 2.2 Sequence of Events During Firing.- 2.2.1 Diagonal Shots, Deviations from the Normal Pattern of Powder Soot Blackening.- 3 Classification of Shot Range Zones.- 3.1 Contact Gunshot (Shot with Muzzle Contact).- 3.1.1 Contact Shot on Naked Skin.- 3.1.1.1 Muzzle Imprint.- 3.1.1.2 Soot in the Bullet’s Track.- 3.1.1.3 Powder Particles in the Entrance Hole and the Bullet’s Track.- 3.1.1.4 Remarks on the Ranges at Which the Term Contact Shot is Valid.- 3.2 Intermediate Range Gunshot.- 3.3 Distant Gunshot.- 4 Qualitative Detection of the Signs of a Close Range Shot.- 4.1 Detection of Powder Tattooing.- 4.1.1 Diphenylamine-Sulphuric Acid (DS) Reaction.- 4.1.2 Lunges Reagent.- 4.2 Detection of the Soot Element Pb.- 5 Morphological Methods of Shot Range Determination.- 5.1 General Principles.- 5.2 Infrared Photography.- 5.3 Sheet Printing Methods, Chemical.- 5.3.1 Sheet Printing Method After Walker and also Mayer and Wolkart.- 5.3.2 Sheet Printing Method After Leszczinski.- 5.3.3 Sheet Printing Method After Suchenwirth.- 5.4 Sheet Printing Method, Physical (Autoradiography).- 5.5 Determination from Powder Tattooing.- 5.6 Imaging with X-Ray, X-Ray Fluorescence.- 6 The Sampling Test Method for the Quantitative Determination of Shot Range.- 6.1 Initial Remarks and Underlying Principles.- 6.2 Emission Spectrum Analysis (ESA).- 6.2.1 General Comments.- 6.2.2 Choice of Lines for Antimony and Iron.- 6.2.3 Sample Taking.- 6.2.4 Carbon Electrodes, Excitation Conditions.- 6.2.5 Spectrograph.- 6.2.6 Extending the Distance of the Shot Range Determination.- 6.3 Atomic Absorption Spectrography (AAS).- 6.3.1 General Comment.- 6.3.2 Apparatus, Detection Limits.- 6.3.3 Taking the Samples, Preparation for Testing.- 6.3.4 Comments on the Measuring Technique, Producing a Calibration Curve.- 6.4 Neutron Activation Analyses (NAA).- 6.4.4 General Comments and Principle.- 6.4.2 Method, Results.- 6.5 Polarography.- 6.6 Other Methods of Shot Range Determination.- 6.6.1 Range Determination using the Bullet-Wipe Ring.- 6.7 Possible Errors in Shot Range Determination.- 6.7.1 The Vinogradov Phenomenon.- 6.7.2 Back-Scattering Effect.- 6.7.3 “Powder Soot Blackening” from Fragmentation of Bullets (“Ghost Powder Soot Blackening”).- 6.7.4 Interference with the Detection of Soot Elements due to Various Physical and Chemical Effects.- 6.7.5 Changes in the Pattern of Powder Soot due to a Muzzle Silencer.- 7 Shot Range Determination for Shotguns.- 7.1 General Remarks.- 7.2 Characteristics of the Barrel, Choke.- 7.3 Shot Patterns—The Diameter of the Shot Pattern as a Function of the Range and Other Parameters.- 7.3.1 Theory.- 7.3.2 Experimentally Determinated Values of ? as a Function of the Shot Range and Other Parameters.- 7.4 Practical Procedures of Shot Range Determination for Shotguns.- 8 References and Further Readings.- 9 Subject Index.