MultipleShot Suicides
Multiple-shot suicides engender controversy due to the misconception that it is impossible to inflict more than one gunshot upon oneself. Tied in with this mistaken belief of instant incapacity are fallacies such as 'the impact of the bullet would send you reeling backwards', 'the gun would fly out of your hand', and so on. Incapacitation can be divided into three major groups 1. Instant incapacitation. This can only result from a cessation in the functioning of the central nervous system via...
Brief glossary Pfc
Ball burnishing A steel ball bearing of the same size as the barrel lands is repeatedly pushed through the bore. This flattens out any irregularities in the bore, leaving a mirror-like finish. A tool with a series of discs each with a profile of the required rifling. Each disc is slightly larger than the previous one so that the whole depth of the rifling may be cut with one pass of the tool. A hardened steel ' button' or ' plug' on the end of a long rod, containing an exact negative of the...
Case example Eps
Another illustrative case on the use of X-ray photographs concerns the case of an old man who dropped dead on the streets of Hong Kong. There were no suspicious circumstances, but to ensure that no pacemakers or anything else was present in the body that could cause problems with the cremation, a standard X-ray was taken. It was at this stage that the shadow of a bullet was seen next to the spine. At the PM, no obvious bullet could be found, but on excavating some calcified material surrounding...
Ultrasonic Cavitation for Restoration
Cavitation is the formation of vapour bubbles in a liquid due to a very localized reduction in pressure. This can be observed in high-speed motor boat propellers where a stream of bubbles is created. The phenomenon is very similar to boiling where bubbles of vapour are formed due to a localized increase in temperature. Any metal object which is subjected to this cavitational effect will be surface etched. In pumps, high-speed propellers and pipes carrying high-velocity liquids, this can be...
Rifles
Rifle actions can be very roughly grouped into single shot, bolt action, self-loading and pump action. Single shot. In single- shot weapons, the barrel can be hinged to the frame, allowing the barrel to be dropped down for loading and unloading, or can have some form of breech block which either swings out, pulls back or slides down to expose the breech end of the barrel. Bolt action. In bolt-action weapons, a turning bolt slides in an extension to the barrel, which is basically the same system...
Unburnt and partially burnt propellant particles
Being much heavier than the carbonaceous material, the propellant particles can be found on the target at much greater distances. With low-powered microscopy, these particles can be located on the target at ranges up to 30 for a handgun and to over 48 for a rifle. With 30 being the approximate arm length for an adult, the presence or absence of propellant particles can be extremely important in determining the sequence of events in a shooting case. Factors influencing the quantity of this...
Hearing Protectors
Hearing protection devices decrease the intensity of sound that reaches the eardrum. They come in two basic forms earplugs and earmuffs. Properly fitted earplugs or muffs reduce noise 15-30 dB. The better earplugs and muffs are approximately equal in sound reduction, although earplugs are better for low-frequency noise and earmuffs for high-frequency noise. Simultaneous use of earplugs and muffs usually adds 10-15 dB more protection than either used alone. Combined use should be considered when...
Case example
This concerned a Hong Kong fisherman who had been illegally fishing in the waters off Vietnam. A Vietnamese gunboat gave chase and when the fisherman refused to stop, the gunboat crew opened fire with a number of AK47s and a 12.7 mm DShK heavy machine gun. The fishing boat took numerous hits from both the AK47s and the DShK. In addition, the captain was hit with a 7.62 x 39 mm bullet and died almost immediately. Another member of the crew took over the control of the boat and continued the...
Case example 1
An interesting case involved the identification of missile holes in a vast 18 ft diameter table which was reputed to be that of King Arthur, a fifth century King of England Biddle, 2000 . The table had been hanging on the wall of the great banqueting hall at Winchester Castle, Hampshire, and it was not until it was taken down for restoration that the missile holes were located. An examination of the table's surface found there to be a total of 45 complete penetrations. X-ray photographs...
Appendix Important dates in the History of Firearms from
The first record of the actual use of gunpowder in Europe is 1247 a statement by Bishop Albertus Magnus in 1280 that it was used at the Siege of Seville in 1247. Roger Bacon gives an account of gunpowder in his Opus 1267 Majus Actually, his account was written in cryptic form. See T. Explosives Pelican Books, 1942 . Hand cannon had appeared in the field of battle during the 1364 Handguns were known in Italy in 1397, and in England they 1375 appear to have been used as early as 1375. The first...
Hearing Loss
It is generally accepted that a continuous noise level of 85 db decibels is the maximum safe level for long-term exposure to steady noise level within the frequency range of about 600-1,200 Hz. The very brief gunfire noises are another matter. Leading hearing specialists stipulate that about 150 db is the maximum peak limit for gunfire noises without impairment of speech perception and 140 db maximum without impairment of good hearing of music and the like. It should be noted that decibels are...
Bullet lubrication
Plain lead bullets must have some type of lubrication on their outside surface to reduce friction with the bore. Jacketed bullets do not generally require any form of lubrication. Lead bullet lubricant generally contains a mixture of vaseline, beeswax and graphite, although modern silicone based waxes are being used to a certain extent. In modern ammunition, this lubricant is held in a groove round the bullet, called a cannelure, which is generally located on the portion of the bullet inside...
Determination of bullet type
As the bullet passes down the barrel, the rifling will tear off small fragments of the bullet. Some of these fragments will remain in the bore and others will be blown out of the bore by the gases following the bullet. Some of these fragments do, however, remain attached to the bullet in the form of sub-microscopic pieces of swarf. As the bullet passes through any material, whether it is human flesh, fabric or wood, these fragments are often transferred to the medium through which it is...
Bullet materials
Modern ammunition comes with a bewildering variety of bullet profiles, materials and construction to cater for every conceivable circumstance. To attempt to cover all the available varieties is beyond the scope of this book. The following, however, covers the basic types of bullet which may be encountered. In small arms ammunition, bullets are either jacketed or unjacketed. Whilst unjacketed bullets can be made from all manner of materials, the most common by far is lead. The lead will be...
ACCIDENTAL DISCHARGE Failure of the safety mechanism
One very common fault in shotgun lock mechanisms of the old external hammer type involves a faulty 'rebound safety'. In this type of weapon, there is an additional bent in the form of a hook rather than a notch called the 'half cock' or 'rebound bent'. As the bent is hook shaped, the sear is firmly locked into place and it should not be able to manually push it forward or to pull the sear out of contact with the bent via the trigger. When in this half-cock or rebound position, the only way of...
Appendix Commercial and General Abbreviations for Bullet Configurations
ACC Accelerator - sub-calibre bullet fitted into conventional cartridge with a plastic sabot. ACP Automatic Colt Pistol. Used as a designation for cartridges designed specifically for self-loading pistol cartridges i.e. 0.380 ACP, 0.45 ACP . Can also be in lower case i.e. 0.380 acp or 0.45 acp . AP Armour-piercing bullet usually with a tungsten core. API Armour-piercing incendiary. As above but with the addition of an incendiary pellet in the nose. BRPT Bronze point. Bronze insert in tip...
Fluted Annular Ringed Helical Perforated and Oversized Chambers
Fluted, annular ringed, helical and perforated chambers exist in a number of modern weapons and can assist in identifying both class and individual firearm characteristics. Cutting grooves in a weapon chamber to improve the weapon' s functioning was first proposed as early as 1914. This was via a patent issued to Giovanni Angelli for various chamber modifications designed to retard and accelerate the extraction of a fired cartridge case. However, it was not until 1920 that the German Mann 0.25...
Introduction Rgb
When attempting to prove that a person has fired a weapon, the detection of gunshot residues GSRs on the hands of a suspect can be of great significance. The use of the scanning electron microscope SEM for this is probably the most important advance in the field of forensic firearms examination since the invention of the comparison microscope. It is important, however, that one has an overview of the history of the subject to place the significance of this advance into its true perspective and...
Brief glossary 1
Rimfire cartridge Round of ammunition In shotgun terminology, the number of lead balls of the same diameter as the inside of the barrel which weighs 1 lb. Thus, a 12-bore shotgun has a barrel diameter of 0.729, and 12-round lead balls of 0.729 in. diameter weigh exactly 1 lb. In terminology applicable to weapons with a rifled bore it is the inside diameter of the barrel measured across the tops of the lands, that is, the raised part of the rifling. Refers to the missile alone. It can be either...
Event Nbh
The true pinfire cartridge emerged. 1 840 It was not until 1840 that we definitely found a breech- 1840 loading needle gun cartridge patented Wm. Bush, Pat. No. 8513 . The Brunswick rifle superseded the Baker model. 1840 Duelling declined in England after 1840. 1 840 The period of decadence of duelling was noticeable for the 1840-1850 production of rather short-barrelled pistols. A few service arms were converted to the percussion cap 1842 system in 1839, and it was officially adopted in 1842....
The Use of Xray Photography
The use of X-rays in the investigation of gunshot wounds can be invaluable to the forensic investigator for a variety of reasons and can help to 1. determine whether part or all of the bullet is still within the body 2. locate the exact position of the bullet 3. locate and determine the type and calibre of bullet where the bullet cannot be surgically removed 5. determine the position of all the pellets and wads in shotgun wounds prior to surgery. In numerous cases that I have dealt with, a...
Ignition of primers in a fire
As far as spontaneous combustion of the priming compound is concerned, the flameless ignition temperature of small arms priming compounds is generally in the region of 190-260 C. This is considerably lower than the ignition temperature for most small arms propellants, which is in the region of 350 C. It can be assumed, therefore, that during a fire, the first thing to spontaneously ignite will be the primer which will, in turn, ignite the propellant. Such ignitions are virtually harmless as the...
Other alternatives to lead
The list of other materials used or under review is exhaustive, and many more will almost definitely follow in the future. At present, the following are just some of those either used or currently being considered 1. soft steel often copper coated to reduce corrosion 2. iron-scrap tungsten Hevi-Steel 6. tungsten-iron-bronze Remington HD Shot 13. - ungsten-tin-iron-nickel Hevi-Shot 14. nitro-steel zinc galvanized steel - Remington. A comparison of the various densities for some of the non-toxic...
Deflection of bullet by glass
A series of tests B.J. Heard, unpublished work with various calibres of weapon fired at laminated windscreen glass held at varying angles has indicated that there is very little deviation of the bullet from its intended path. These can be conveniently illustrated by the following table Table 4.6 Table 4.6 Deflection of bullet from intended path at three different impact angles. Table 4.6 Deflection of bullet from intended path at three different impact angles. A very limited number of tests...
Introduction Dxi
In armed robbery incidents where no shot has been fired, it is often necessary to demonstrate a link between the suspect and a recovered weapon. As GSR particles will not be present on the hands, the only way this can be effected is through the detection of any metal traces which may have been transferred from the weapon to the hands. The quantity of metal traces transferred from the weapon to the hand is extremely small and probably below the threshold for analytical detection by conventional...
Identification of Calibre from the Bullet Entry Hole Introduction
In skin and fabrics, it is, unless a wadcutter-type bullet is used, all but impossible to determine the calibre of a missile from its entry or exit hole. Wadcutter bullets, as discussed earlier, are intended for target practice. As such, they are designed to cut a clean hole through the target to facilitate the determination of the shooter' s accuracy. When round-nosed or even hollow-point bullets are used, the hole produced by the bullet is very much smaller than its calibre. In skin, this is...
Formation of stria
During the firing of a weapon, the individual stria are transferred from the hard surface of the weapon on to the softer surface of the bullet or cartridge case during the firing. As the tremendous pressures build up during the first few moments of firing, the base of the bullet swells to fill and so obturate the weapon' s bore. As it passes down the barrel, the minute irregularities in the bore form longitudinal scores or striations down the length of the bullet. Some of these are obviously...
Oversized chambers
The German FG42 Paratroop rifle 42 and some issues of the MP44 make use of the same principle as a fluted chamber in that they have chambers that permit escape of gases around the cartridge case. These chambers, however, are not conventionally fluted, but are of larger diameter for approximately the rear half of the chamber. This allows the gases to escape into this area, thus equalizing the pressure and easing extraction. A list of some of the more current weapons using these chamber markings...
Event 1
The broad arrow as a sign of government property was adopted during the reign of George I, and the word TOWER was marked on the lock plate of many of these The French established their 'Manufacturers Royales' at Charleville, St. Etienne and Maubeuge. The large box lock type of pistol made its appearance. A few hammerless flintlock sporting guns were made by Stanislaus Paczelt, of Prague in Bohemia. The use of pistols for duelling purposes became general as the practice of carrying the rapier or...
Bullet base configuration
Whilst most small arms bullets have a base which is the same diameter as the body, long-range rifle bullets have the rear section of the bullet tapered. This is to reduce base drag and is referred to either as a boat-tailed bullet US nomenclature or a streamlined bullet British nomenclature . These bullets are generally military, but can also be encountered in commercial ammunition. A heeled bullet is one in which the rear portion of the bullet, which fits into the cartridge case, is reduced so...
Individual characteristics on cartridge cases
The parts of a weapon which imprint class characteristics on the fired cartridge case have, of course, been individually manufactured. The manufacturing process involves cutting, drilling, grinding, hand filing and, very occasionally, hand polishing. Each of these processes will leave individual characteristics in much the same way as the boring process, which is the initial step in making a barrel. An example which conveniently illustrates the production of individual characteristics would be...
Sample Collection
The methodology for sample collection for GSR analysis is simplicity itself. The most commonly used technique uses a 1 x l cm strip of double-sided adhesive tape stuck onto a thin acetate strip. The acetate strip allows the adhesive surface to be conveniently manipulated without any fear of contact with the sampler's hands. One of these tapes is used to take samples from each of the four areas as illustrated in Figure 6.3. During the taking of the samples, the skin must be stretched as much as...
How We Hear
Sound waves enter the outer ear and travel through a narrow passageway called the ear canal, which leads to the eardrum. The eardrum vibrates from the incoming sound waves and sends these vibrations to three tiny bones in the middle ear. These bones are called the malleus, incus and stapes. The bones in the middle ear amplify, or increase, the sound and send the vibrations to the snail-shaped cochlea, or inner ear. The cochlea is a fluid-filled organ with an elastic membrane that runs down its...
External Ballistics Introduction
External ballistics is the study of the missile -s flight from when it leaves the muzzle until it strikes the target. It is an extremely complicated subject and before the advent of powerful desktop computers, the calculations were laborious and time consuming, requiring the use of many mathematical tables. With modern computers and ballistic programmes, it is now possible to calculate the most complex trajectory equations with just a few key strokes. The two main factors which affect the...
Fluted chamber
Fluted chambers are longitudinal flutes which are deeper at the forward end of the chamber and taper off towards the rear. These allow the gases produced on firing to flow back over the outside of the cartridge case during firing. This counters the internal pressure and ' lubricates' the case, thus facilitating the extraction process. This is utilized in blowback and delayed blowback weapons where pressures are relatively high, thus making extraction difficult Figure 4.18 . Figure 4.18...
Introduction 1
It is generally thought that a bullet will, after penetrating glass, experience a large deviation from its normal flight path. There is some confusion over this with published papers reporting extremes. A paper by Harper 1993 reported a relatively small deviation as does Rathman 1993 , whilst Thornton Thornton and Cashman, 1986 reports a much larger deviation. Papers by Haag 1987 describe the measurement of deflection Garrison 1995 , the penetration of auto body parts in general and Bell 1993 ,...
Penetration of laminated glass
When struck by a bullet, laminated glass which consists of two sheets of glass bonded together with a plastic film will first bulge away from the site of impact. This causes a series of radial cracks. As the glass continues to bulge, concentric cracks are produced, the quantity of which are determined by the energy given up by the bullet to the glass Salferstein, 1982 . The quantity of crushed glass round the periphery of the entrance hole is also a function of the energy given Easily deformed,...
Discharge due to inappropriately low trigger pressure
For target use, trigger mechanisms are often 'tuned' to give a smoother, lighter trigger pull. It is not unusual to find target pistols and rifles with trigger pulls in the region of 1 lb. Accepted commercial and military trigger pulls vary tremendously, but generally, the following could be considered as acceptable Whilst a 'tuned' trigger pressure as low as 1 lb may be totally acceptable in the very specialized arena of a target shooting competition, in other circumstances, it can be...
Theory of recoil
As seen earlier, the velocity of the bullet leaving the weapon or the velocity of the recoil of the weapon is calculated by the following formulae M is the mass of the gun or bullet F is the force in pounds, and T is the time during which it acts. During the period which this force is acting on the bullet, it is, therefore, also acting with an equal degree of force on the gun. If the velocity of the bullet is v, the mass of the bullet m, the rearwards velocity of the gun V, the mass of the gun...
Event Crp
There never was an official British State-maintained arms 1855 factory until the government established Enfield as a government factory when the Birmingham gunmakers struck for higher wages in the middle of the Crimean War. Whitworth rifles were produced. 1 857 Duelling continued in India to the date of the Mutiny. 1857-1858 The first recorded European revolver for central fire 1859 cartridges appears to be that patented by Perrin and Delmas in 1859. The first effective and widely used magazine...
Range of firing estimation on badly decomposed bodies BJ Heard unpublished paper
Estimating the range of firing on a badly decomposed body can, unless a shotgun has been used, prove to be extremely difficult. The putrefying tissue either masks the presence of residues or they are removed as the outer layers of skin slough off. A case where this problem was of considerable importance involved the shooting and subsequent dismembering of a young insurance sales woman. After being shot and then dismembered, the body parts were placed into several black plastic bags and dumped...
Purposeful eradication of individual characteristics
It is often assumed that the last part of the rifling to touch the bullet before it leaves the barrel produces the only stria of any significance. In part, this is true as the last part of the bore does have the ability of erasing any stria which came earlier. It is also true that if the marks made nearer to the breech were deeper than those at the muzzle, then they will not be erased. There have been many instances where the last few inches of a barrel have been sawn off in an attempt to...
Scorching
This is caused by the incandescent gases as they emerge from the muzzle of the weapon. Although they initially leave the barrel at a temperature of around Figure 5.9 Discharge residue deposits for various types of ammunition at the same range a Winchester b Sellior and Bellot c Norma d Rem UHC. Figure 5.9 Discharge residue deposits for various types of ammunition at the same range a Winchester b Sellior and Bellot c Norma d Rem UHC. Figure 5.10 Discharge residue patterns for the same ammunition...
Further Reading
Blackmore, H. 1965 Guns of the World, Batsford Press, London. Blair, C. 1968 Pistols of the World, Batsford Press, London. Hoyem, G.A. 1981 History and Development of Small Arms Ammunition, I-III, Armory Press, Missoula, MT, USA. HMSO 1929 Textbook of Small Arms, His Majesty's Stationery Office, London. Mathews, J.H. 1962 Firearms Identification, I, II amp III, University of Wisconsin Press, Madison. Smith, W.H.B. 1968 Book of Pistols and Rifles, Castle Books, New Jersey. Smith, W.H.B. 1970...
Shotgun ammunition
Shotgun ammunition is once again a confusing subject with the smaller calibres being referred to by the approximate bore diameter, that is, 0.22, 9 mm, 0.410. Once past 0.410, the calibre changes to a bore' or if using the American nomenclature gauge' size where the bore is the number of lead balls of the same diameter as the inside of the barrel which weighs 1 lb. Thus, a 12- bore shotgun has a barrel diameter of 0.729 and 12 round lead balls of 0.729 diameter weigh exactly 1 lb. It should be...
Ferrozine Test
Q39. How do you know that the results obtained from this test were not caused by a kitchen knife, or a knife fork and spoon A39. Firstly, most kitchen utensils are made from stainless steel or are nickel or chromium plated, none of which gives a positive result to this test. In addition, this whole test relies on the interpretation of the visualized marks on the hands. The examiner will, therefore, have to prove beyond reasonable doubt that the marks observed were those from a weapon and not...
Recoil energy
All the above is concerned with the velocity of the gun's recoil, which tells us very little about the actual force, or more correctly, the energy of the recoil. The energy of the recoil is calculated by use of the formula The kinetic energy KE of the recoil, or the recoil energy, gives us a much clearer picture of the actual forces involved. The recoil energy of a weapon and, for that matter, the kinetic energy of a bullet are calculated in exactly the same way and are measured in foot pound...
Glossary
Abbreviation for Automatic Colt Pistol. Used to designate calibres designed for use in Colt self-loading pistols. The mechanism of a firearm. A design for a semi-automatic firearm wherein the breechblock is stationary and the barrel moves forward by gas pressure to open and eject the cartridge and re -cycle the action. A design found in semi-automatic and automatic firearms where the inertia of some component, usually supplemented with a spring, is the main locking force and no mechanical...
Weapon Types and Their Operation
Terrible confusion exists as to what is a pistol, revolver, self-loading pistol and automatic. This is very basic firearms nomenclature, but it is often wrongly applied. The use of the correct term is absolutely essential if any credibility is to be maintained. This chapter attempts no more than to carefully explain the correct usage and, where they exist, alternatives which one might encounter. There are three basic types of handgun single shot, revolving and self-loading pistols. Such exotica...