Time since discharge of rifles

The estimation of time since the latest discharge of rifles has been achieved by the SPME sampling technique and the GC-TEA analytical system. An unidentified compound, designated as the TEA2 compound, was detected in all the rifles investigated. The same compound was observed in shotguns and spent cartridges in our previous work. This compound escapes rapidly from the inside of rifle barrels, but can still be detected there one to two months after the shooting. The decrease of the TEA2 peak with time after shooting is non-exponential, and the curve-fitting procedure proposed for the estimation of time since discharge of shotguns can be applied also for rifles.     

Unusual sources of Sn in GSR. An experimental study by SEM and IBA

Gunshot Residue (GSR) produced by the discharge of a firearm often provides very useful information in criminal investigations in cases involving the use of firearms. Scanning Electron Microscopy equipped with an Energy Dispersive X-ray Spectrometer (SEM-EDS) is typically used worldwide to visualize micrometric particles constituting GSR and to analyse their elemental composition. The 2017 ASTM Standard guide for gunshot residue analysis by scanning electron microscopy/energy dispersive X-ray spectroscopy specifies that “Particles classified as characteristic of GSR will have one of the following elemental compositions: Lead, antimony, barium; Lead, barium, calcium, silicon, tin”. For the first time, the presence of an additional element, such as Sn, plays a key role in ASTM particle classification. It is known that some ammunitions, used for pistols, revolvers and rifles, contain tin foil discs for sealing the primer mixture into the cup, resulting in GSR particles containing Sn. The authors faced some cases in which Sn was unexpectedly found in GSR particles from a 0.22 Long Rifle derringer and from some 12 gauge shotguns. No tin foil discs are used in rimfire ammunitions and there is no published evidence of tin foil discs in shotshell ammunitions. Following a “case by case” approach, experimental research has been carried out to explain how Sn can be present in GSR particles when the last discharged cartridge also does not contain any Sn either in components and in the explosive charges.Moreover, the use of Particle Induced X-ray Emission (PIXE) showed the capability to overcome overlap ambiguity of Sb and Sn peaks in the X-ray spectra, being a possible key issue in real shooting cases if Sn quantities are below the lower limit of SEM detection, especially when Sb is also present.     

Time since discharge of shotgun shells

A technique for the estimation of time since discharge of a given class of spent shotgun shells is presented. The technique involved the use of SPME (Solid Phase Microextraction) sampling from the atmosphere inside spent shotgun shells. Compounds absorbed on the SPME fiber were desorbed and analyzed with GC-MS. The decrease in concentration of the combustion product naphthalene was monitored in all shells over a two-month period. Three conditions were examined to prevent naphthalene from escaping prior to testing the shells. A glass vial was successfully incorporated to halt the dissipation of naphthalene. At room temperature the naphthalene peak can be measured for several months and the curve-fitting data can lead to an estimation of time since discharge.     

Modification Methods of Blank Pistols in Turkey in 2006

Abstract:  This study describes the modification methods of blank cartridge firing pistols in Turkey. We have examined cases submitted to the Aydın Regional Criminal Laboratory of Turkey in 2006. In total, 95 modified pistols and 300 modified cartridges were examined. The blank cartridge firing pistols are guns which look similar to "real" pistols, however, there are blockages in their barrel in order to prevent the discharge of a bullet. However, as a result of simple modifications, these pistols can be easily converted into "real" firearms. Studied modification methods are removing the obstruction from the barrel, removing the partial obstruction from the barrel, sleeving a smaller diameter tube into the original barrel, using a replacement barrel, and rifling the original barrel. Special cartridges for these modified pistols are also produced. These modified pistols and cartridges were evaluated in respect of the converting methods.     

有机爆炸物的现场非介入性检测——顶空固相微萃取一真空气相色谱质谱法

本文考察了顶空固相微萃取在有机爆炸物现场非介入性检测中的适用性。由固相萃取（SPME）纤维头吸附的有机爆炸物用真空气相色谱一质谱联用仪进行检测。该方法所需的洗脱温度低,色谱分离时间短。SPME适用于提取蒸汽压不低于2．4,6-三硝基甲苯（TNT）的挥发性和半挥发性有机爆炸物,如较易挥发且不稳定的化合物三过氧化三丙酮（TATP）的非介入性检测就可以应用该方法。本研究使用静态顶空,尽可能地减少顶空体积,实现了较高的灵敏度。在现场,SPME方法的灵敏度受环境温度的影响较大：由于样品的蒸汽压未达到平衡,在固定顶空体积和萃取时间的条件下,SPME纤维头萃取的样品总量随温度的提高而增加。在有合适容器的情况下SPME纤维头上萃取的样品在取样3天后仍然能顺利检测。     

Characteristics of firearms and gunshot wounds as markers of suicide.

Data from a total of 1,200 cases that the Medical Examiner of Dallas County, Texas, ruled as suicide with a firearm have been compared with the results of forensic laboratory examinations and tests; 75% are with handguns and 25% are with long guns. The incidence of suicides by gender yields 82% males and 18% females, with the most common entrance site being the head. With regard to racial distribution of persons committing suicide, > 88% are white in the study population group, which is 76% white. Data are presented for the incidence of blood detected inside and on the muzzle end of the barrel of the firearm, and for the persistence of blood inside the barrel even after the weapon was discharged to obtain test bullets. The analysis of handwipings for primer residues shows that "positive" results are obtained for approximately 50% of the revolvers and approximately 32% of the pistols when the caliber is > 22. Other projects such as transfer of gunshot residues to the hand by simply handling the weapon, the incidence of single-contact wounds in homicide versus suicide cases, and the percent of positive identification of bullets with weapons submitted are described.     

Morphology of bullet entrance wounds in palms and plantae (author's transl)

Tests shots with hand weapons of .22, .25, .32, .357, and .45 calibre were made to find out whether bullet entrance wounds in palms and plantae are very different from such wounds in other parts of the body. As far as shots without contact between muzzle and skin were concerned, the following characteristics were noticed: (1) Entrance holes from pistols and revolvers of the same calibre were smaller in palms and plantae than in other parts of the body. (2) There is no abrasion collar as typically found in other regions. (3) The corneum of epidermis around the entrance hole is lifted off and torn radially. These unusual findings are most probably the result of the particular texture of the palmar and plantar epithelium.     

Forensic veterinary radiology: ballistic-radiological 3D computertomographic reconstruction of an illegal lynx shooting in Switzerland

The most popular handgun in Brazil is the single round-barrel caliber 0.38 revolver. In recent years, however, owing to the modernization of police arms and their availability on the legal and illicit markets, pistols have become increasingly popular and currently represent about 20% of police seizures. In a previous paper we presented a novel collection method for gunshot residues (GSR) using a sampling procedure based on ethylenediamine-tetraacetic acid (EDTA) solution as a complexing agent on moistened swabs with subsequent detection using sector field-high resolution-inductively coupled plasma-mass spectrometry (SF-HR-ICP-MS). In the present paper, we discuss the capability of this methodology to identify antimony (Sb), barium (Ba) and lead (Pb) on the hands of volunteers after shot tests with 9 mm and 0.40 in. caliber pistols. Two types of munitions were tested: 9 mm Taurus and clean range. The use of a technique with high sensitivity, such as SF-HR-ICP-MS, permits the identification of low concentrations (less than 1 microg/L) of metals in firearm residue and constitutes a powerful tool in forensic science. We also discuss the importance of the sampling procedure, including collection from a different body part than the gun hand of the suspect. Comparison of the analytical data obtained allows clear discrimination between samples from the hands of shooters and non-shooters.     

Relation of Kinetic Energy to Contact Wounds of the Head by Centerfire Rifles and Shotgun Slugs

Wounds of high‐energy centerfire rifles and shotguns represent distinctive injuries of forensic importance. Previous studies of contact wounds have shown variability in the potential of these weapons to produce bursting wounds of the head. The present study analyzed contact head wounds owing to 26 centerfire rifles and nine shotgun slugs and compared them with respect to weapon, ammunition, entry wound site, and projectile kinetic energy. The bursting effect, defined for this study as disruption of at least 50% of the head, occurred in 25/35 of cases and was related to kinetic energy. Bursting was associated with energies <2700 ft‐lbs in 12/22 cases and energies >2700 ft‐lbs in 13/13 cases. The volume of gunpowder gas injected into the wound was considered as contributing to the bursting phenomenon. There was no relation of bursting to the specific entrance wound site, type of ammunition, or projectile fragmentation.     

Investigation of the variability in the tool marks produced by modified blank firing pistols on fired 7.65 mm projectiles

Firearms identification has an important place in forensic ballistic investigations since the weapons are widely used in criminal offences. Firearm examiners resolve many case files, through the use of automatic systems or comparison microscopes. Advanced forensic technologies like BALİSTİKA helps to record and analyze non standard ballistic evidence. In today's world, with the ease of access to materials and production technique information, pistols modified from blank firers are frequently encountered as crime tools. In this study, the characteristics of 7.65 mm fired cartridge cases obtained by controlled shots from blank firing modified pistols were examined, and their detection performances were compared by means of the Balistika system. Although distinctive differences are not expected after successive test shootings, balistically important changes were seen after the use of blank firing modified pistols and the 3D imaging system proved to be useful in observing such differences. The analyses showed that the modifications in weapons lead to variation in the ballistic characteristics and reduce the accuracy of the detection performance, which may result in flawed forensic decisions. It was also found that the deviations in ballistic impressions of modified blank firing pistols were greater than that of standard fabricated and hand-made pistols. This unique study contributed to the forensic sciences literature by focusing on the impact of modified weapons on ballistic characteristics.     

Suicidal gunshot to the nape from a small-bore rifle

A 55-year-old man was found dead on the bed lying on his side in a pool of blood with a bullet entrance hole in the nape. Behind his body, a semi-automatic rifle Remington Nylon, cal. .22 LR, was detected. As the gunshot entrance site was rather unusual for suicide, a forensic autopsy was performed, which showed a contact shot to the nape with the bullet path running upward to the left frontal area. The man had been treated with citalopram for delusional depression, so that a suicidal act seemed plausible, and the autopsy and criminalistic findings were also compatible with this assumption. A remarkable fact of the present case is that a long firearm had been used. Reports on suicidal shots to the nape are comparatively rare in the medicolegal literature and usually refer to pistols or revolvers.     

Wounds caused by contact with muzzle-lift relief ports (Mag-Na-Port).

Fan-shaped stippled burns were produced on the skin when a revolver whose barrel had been modified by the Mag-Na-Port process was fired twice with the side of the muzzle in contact. A grazing wound was produced by one bullet, and an oblique entry was produced by the other. The characteristics of Mag-Na-Port wounds and test shots are described, and these are compared with test shots from two other higher power revolvers.     

Time periods of GSR particles deposition after discharge-final results

The elemental objects of the research study are: determination of time periods corresponding to gunshot residue particles (GSR) deposition after the shot from selected pistols and a revolver, and evaluation of the deposited particles number. For several shooting experiments were used a pistol CZ model 85, caliber 9 mm Luger with common ammunition 9 mm Luger FMJ Sellier & Bellot, a pistol CZ model 70, caliber 7.65 mm Browning (32 ACP) with common 7.65 mm Browning FMJ Sellier & Bellot ammunition and a revolver S&W Modell 60, barell length 2-1/8', cal. .38 Special with common Sellier&Bellot (FMJ) ammunition. The results of the study have indicated the behavior of GSR particles deposited after a single discharge. The overall time interval of GSR particles deposition and the number of deposited particles with the above mentioned arms and ammunition were established. The results can potentially be used for clarifying the situation at crime scenes and for subsequent interpretation of GSR evidential value in caseworks.     

Suicide by firearms: a 15-year experience.

A retrospective review of 1704 cases of suicide involving firearms investigated by the Bexar County Medical Examiner's office between 1984 and 1998 was performed. The age distribution was similar in male and female victims, and the type of weapon was not associated with age. Approximately 78% of the victims used a handgun (87% of female and 76% of male victims). In 4.0% of head wound cases, the site of the entrance wound was the back of the head. Thus, this report refutes the common belief that all gunshot wounds to the back of the head represent homicides. In 1.9% of the cases, the wounds were inflicted at intermediate range. With handguns, the right temple was the most common site, but with rifles and shotguns, the most common site was the mouth.     

Ballpoint pen inks: the quantitative analysis of ink solvents on paper by solid-phase microextraction

We wish to describe further developments to a method previously reported on the detection of 2-phenoxyethanol in ink. The solid-phase microextraction (SPME) sampling technique, together with gas chromatography-mass spectrometry (GC-MS), has been used to quantify solvents in writing ink. In conventional approaches, the analysis of ink on documents requires some degree of destructive sampling. The methods commonly used remove ink samples from paper using a scalpel or a paper punch. To avoid document destruction, a sampling cell was constructed that allows solvents to be adsorbed directly onto the SPME fiber from the headspace above the document surface. Analytes (ink volatiles) are then desorbed from the SPME fiber on a gas chromatograph equipped with a mass selective detector (GC-MSD). With this method, it was possible to detect the presence of ink solvents on documents for a period lasting up to c. 2 years.     

Patterned imprint mark due to the folded shoulder stock: A possible finding in contact shots from submachine guns

The muzzle imprint (barrel mark) is a pressure abrasion typically associated with contact shots. Apart from the contours of the actual muzzle profile, other constructional parts such as the front sight and/or the recoil spring guide of semiautomatic pistols may be imprinted next to the bullet entrance wound. In some types of submachine guns the shoulder stock can be folded forward so that its end partly encircles the muzzle. If such a weapon was in contact with the skin at the instant of discharge, a corresponding contusion mark is to be expected. The imprint configuration may point to the type of weapon and to the way in which the gun had been held when firing the shot. The paper presents the injury pattern in a 36-year-old man who committed suicide with a Scorpion SA Vz 61 submachine gun cal. 7.65 mm Browning from former Czechoslovakia.     

Shotcup petal abrasions in close range .410-caliber shotgun injuries

Shotcup petal abrasions centered around a shotgun wound of entrance are generally thought to occur at a range of 30 to 90 cm. A suicidal .410-caliber shotgun injury of the right eye is described in which typical petal abrasions were noted around the entrance wound. However, significant soot deposition around the wound suggested that the range of fire was less than 30 cm and perhaps closer to 15 cm. Test-firing of the weapon and ammunition used by the decedent showed some spread of the shotcup petals at a range of 7.5 cm, progressing to maximum spread at 30 to 52.5 cm. Further testing with other .410 ammunition, containing shotcups, confirmed the spread of shotcup petals at ranges less than 30 cm, irrespective of manufacturer, shotshell length, and birdshot size. When a variety of shotguns were tested, it was found that one weapon with a very short barrel and cylinder bore did not exhibit petal spread until a range of 30 cm was reached. The remaining shotguns, with longer barrels and full choke, all demonstrated definite petal spread at a range of 12.5 cm. The long, narrow configuration of .410 shotcup petals may explain their early spread and the production of petal abrasions at ranges of less than 30 cm.     

SPME-GC-MS（SIM）对人体手部气味的分析鉴别

目的探讨对人体手部气味分析鉴别的方法。方法以玻璃珠为采样介质,采用顶空固相微萃取及气-质联用选择离子监测（SIM）法分别对不同人体手部气味中主要挥发性成分：醇、酚、醛、酮、酸、酯6类物质进行测定。结果除了酸类和酚类物质不能用作区别不同人体气味的指标性成分外,其它4类物质均可作为鉴别不同人体气味的指标性成分。     

Canadian firearms legislation and effects on homicide 1974 to 2008

Canada has implemented legislation covering all firearms since 1977 and presents a model to examine incremental firearms control. The effect of legislation on homicide by firearm and the subcategory, spousal homicide, is controversial and has not been well studied to date. Legislative effects on homicide and spousal homicide were analyzed using data obtained from Statistics Canada from 1974 to 2008. Three statistical methods were applied to search for any associated effects of firearms legislation. Interrupted time series regression, ARIMA, and Joinpoint analysis were performed. Neither were any significant beneficial associations between firearms legislation and homicide or spousal homicide rates found after the passage of three Acts by the Canadian Parliament--Bill C-51 (1977), C-17 (1991), and C-68 (1995)--nor were effects found after the implementation of licensing in 2001 and the registration of rifles and shotguns in 2003. After the passage of C-68, a decrease in the rate of the decline of homicide by firearm was found by interrupted regression. Joinpoint analysis also found an increasing trend in homicide by firearm rate post the enactment of the licensing portion of C-68. Other factors found to be associated with homicide rates were median age, unemployment, immigration rates, percentage of population in low-income bracket, Gini index of income equality, population per police officer, and incarceration rate. This study failed to demonstrate a beneficial association between legislation and firearm homicide rates between 1974 and 2008.     

Firing distance estimates with pellet dispersion from shotgun with various chokes: an experimental, comparative study

There are several studies suggesting models for firing distance estimation due to pellet dispersion, but few of them consider the degree of choke of a shotgun. The purpose of this research is to suggest some models for estimation of the firing distance for choked and cylinder bore shotguns. Twelve gauge with full chokes, and 12 and 16 gauge with cylinder bore shotguns were fired with #2 and #5 shots from 75, 100, 300, 500, and 1000 cm distances. Statistically significant pellet dispersion values were found for each shotgun by using #2 and #5 shots for different firing distances. All the data obtained were analyzed with linear regression and four models were constituted. Investigators should use special formulae for each shotgun, degree of choke, and pellet type while determining the firing distance. Therefore, more experimental and comparative studies should be designed for each type.