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Highlights User expects his weapon to be light and reliable and to perform multiple times firing per unit time at the same time. In today's technology, the maximum number of firings can be made per unit time with steel barreled weapons, but in composite barrels; many problems occur due to overheating, strength and reliability. Meeting these opposite demands is an engineering problem. In this study, the design of a composite‐steel combination light gun barrel is studied. Firstly, pressure distribution through the barrel has been calculated using Vallier‐Heydenreich method. According to the calculations, analysis has been conducted using both steel barrel and composite barrel. After the analysis, a composite barrel has been manufactured and testing has been conducted on an all‐steel barrel and the manufactured composite barrel. Composite is carbon fiber and resin is epoxy resin. In composite material, carbon fiber is preferred at the rates of 50% and 60%, the material of the steel barrel is AISI 416R stainless steel. The manufactured steel barrels have the same outer diameter but different wall thickness ratios, firing tests were conducted in such a way that the number of shots per unit time was the same. Stress distribution within a gun barrel was calculated using Vallier‐Heydenreich method. Design and finite element analysis analysis for an all‐steel gun barrel and a composite gun barrel was conducted. A composite gun barrel was manufactured; by using composite materials, the barrel was lightened by 24.8%. The manufactured composite gun barrel and an all‐steel gun barrel were tested by firing over 2500 shots. [ABSTRACT FROM AUTHOR]

The discovery of a specific form of Late Neolithic object in northeast Poland, commonly interpreted as reed arrowshaft straighteners, prompted investigation into the possible use of reed for archery in the European past. To examine the archery qualities of this raw material, and thus the likely rationale behind the manufacture and use of reed arrowshafts, a number of mechanical and experimental analyses were conducted. The results presented here indicate that reed was well suited for prehistoric archery. This is demonstrated above all by the arrowshaft stiffness required by this discipline, defined as the spine‐force, but also both the technological ease of production of arrows and their ballistic capabilities. [ABSTRACT FROM AUTHOR]

In examining deaths resulting from gunshot wounds, it is important to describe the wound pathway created by the projectile. Forensic pathologists must identify all entrance and exit wounds and account for all projectiles. Occasionally, confusion arises as to whether a skin defect represents an entrance wound or not, an exit wound, or some other type of wound. Herein, we propose the descriptor "bullet track skin defect" as a formal description for a superficial skin defect created along the pathway of a projectile within the body. Specifically, we define the "bullet track skin defect" as a partial‐ or full‐thickness skin defect produced by a projectile traveling beneath the skin in a relatively tangential fashion as part of a wound pathway within the body. It is somewhat analogous to a traditional graze or superficial tangential wound, wherein the projectile traveling outside the body strikes the skin tangentially from above, without entering the body. However, the projectile is already traveling within the body with the bullet track skin defect, disrupting the skin tangentially from below rather than from above, without exiting the body. Although these defects are not a common presentation of gunshot wounds, they are certainly not rare. With this case series, we suggest that such defects may be referred to as "bullet track skin defects." Alternative language that can substitute for "bullet track skin defects" includes "bullet track skin wounds" or "bullet track cutaneous defects." [ABSTRACT FROM AUTHOR]

Researchers use a variety of target materials, and sometimes combinations of materials, in their archaeological experiments to examine thrust‐spear or projectile penetration, impact angle, durability, and other issues involving prehistoric hunting weaponry. This variety of target materials is beneficial to archaeological science in several ways, but it may also hinder the comparison of results because many of these target materials do not necessarily share similar physical properties. Here, we assess the penetration properties of four different target materials—store‐bought meat, clay, and two types of gelatin—via static penetration tests of a modern broadhead‐tipped arrow and a stone‐tipped projectile attached to an Instron Universal Materials Tester. Our analyses of load‐deflection curves, peak load, and work energy demonstrate how the four target materials are similar in some ways but different in others, which suggests that researchers may strategically employ one or several depending on the question asked or hypothesis tested. [ABSTRACT FROM AUTHOR]

Soot is deposited from 20–30 cm from the muzzle of most handguns and arranged concentrically around the entry wound. We examined a case of a self‐inflicted gunshot wound from a 9‐mm pistol that left an unusual pattern of soot deposition consisting of two circular 3‐mm deposits of soot located 2 cm from the entry wound. Examination of the weapon and test‐firing it against a cloth reproduced the soot deposits, which were caused by two ports on the top of the barrel. Examination of the weapon and comparing the barrel with the entry wound and surrounding skin may provide important information about the type of weapon, the muzzle‐to‐target distance, and atypical soot deposits. [ABSTRACT FROM AUTHOR]

The individual and synergistic effects of multi‐walled carbon nano tubes (MWCNT) and graphene nano‐platelets (GNP) on the ballistic performance (low and high velocity) of functionalized Kevlar reinforced polymer matrix composites have been investigated. Low‐velocity impact tests were carried out on the composite targets (6 layers) using a gas gun setup. Surface hardened conical nose projectiles of 10 mm diameter were used and the inlet velocity was in the range of 122–128 m/s. Similarly, high‐velocity ballistic impact experiments were conducted on the targets (24 layers) using a 9 mm full metal jacketed (FMJ) projectile with an initial velocity of 430 ± 15 m/s. Acid treatment was done to functionalize the Kevlar fiber surface. From the low‐velocity impact experiments, the hybrid targets had better ballistic resistance when compared to the unfilled and individually filled nanocomposites. A reduced projectile exit velocity, improved impact energy absorption (32.5 J), and an improved energy absorption percentage of 27.57 were observed for the hybrid combination. Similar improvements were observed during high‐velocity ballistic experiments which were evident from the fractographic analysis. The macroscopic investigation on the target containing both the nano‐fillers had the least penetration depth of 5.8 mm and a high damage area compared to the other targets. This is due to the addition of f‐MWCNT and f‐GNP which has increased the matrix toughening and functionalization of Kevlar which increased the interfacial bonding. In addition, the crack bridging property of CNTs and encapsulation behavior of graphene due to stacking has synergistically improved the overall toughness of the composites. [ABSTRACT FROM AUTHOR]

Assessment of wound characteristics and the identification of various constituents of firearm discharge at autopsy play a key role in the determination of range of fire. In relation to wounds caused by shotguns, identification of the wad within the wound track, or of injury caused by the wad, is typically thought to suggest a fairly close range of fire. We present a case of a fatality due to a shotgun slug wound where the presence of the wad within the decedent's body was proposed by defense at criminal trial to favor accidental close range discharge during a struggle for the weapon—as opposed to the prosecution's contention of intentional firing of the weapon from a greater range and through an intermediate target. We undertook test firing of a shotgun of similar design to that which was fired during the interaction (a 12‐gauge pump‐action shotgun) using shotshells consistent with the slug that was recovered from the body (Winchester Super X brand), which demonstrated that the non‐attached fiber wad present in this shotshell design can accompany the slug over distances of at least up to 22 feet (6.7 m) and even after transit through intermediate targets such as a vehicle headrest. These novel data provide assistance with estimation of range of fire in instances of injuries caused by shotgun slugs. [ABSTRACT FROM AUTHOR]

A "plated bullet" has a thin layer of electroplated metal covering the lead core of the projectile. In certain situations, this thin layer of electroplated metal can fracture upon discharge of the firearm. When such fracturing occurs, vaporous lead can escape through the fracture lines of the spinning projectile, resulting in a spiral‐shaped deposition of dark residue surrounding a central bullet defect. The spiral‐shaped pattern is referred to as "comet‐tailing," or the "vortex effect." In this report, three homicide cases with associated comet‐tailing are presented. Police, death investigators, and forensic pathologists should be aware of this unique finding. [ABSTRACT FROM AUTHOR]

Black powder weapons are rarely used in countries where access to firearms is easy. Poland has a fairly restrictive law regarding possession of firearms but under the Weapons and Munitions Act of May 21, 1999, as further amended, the possession of black powder weapons using separate loaded ammunition and manufactured before 1885, or replicas thereof, is legal without a permit. When the amendment was introduced, forensic pathologists anticipated a rush of cases involving such weapons, mainly suicides, but also accidents and homicides, but in our own practice in Lodz over the past 10 years (2010–2019) we have encountered only 7 such cases. Although the number is not particularly high, it does nevertheless account for nearly one‐fifth of all gunshot deaths in the area. The aim of this paper is to present a series of deaths involving the use of black powder handguns. In analyzed cases, the victims were mostly men, they were sober, and their manner of death was suicide. As far as age was concerned, no regularity was found. All black powder handgun shots were characteristic enough in comparison with those from conventional firearms that they could be identified easily—the entrance wounds were larger than usual, there was a lot of gunpowder around them and in the wound canal, the bone fractures were extensive. Analysis of the literature and of our own material indicates that easy availability is not the only factor affecting the choice of a weapon; ease of use and reliability are also important. [ABSTRACT FROM AUTHOR]

With three‐dimensional (3D) laser scanning technology and software packages, the practice of documenting and measuring bullet trajectories has benefited from greater accuracy and reproducibility. This study investigated the accuracy and reproducibility of the bullet trajectory tools in the software package, FARO Zone 3D (FZ3D). Twelve participants were provided laser scanner data for 21 bullet trajectories on drywall panels with impact angles between 25° and 90°. When the impact plane was manually aligned by the operator, 75% of the absolute errors were within 0.91° and 0.98° for the azimuth and vertical angles, respectively. The vertical angle improved to 0.47° when impact plane alignment was taken with respect to gravity (no operator influence). Thus, manual alignment is shown to be subject to greater error than alignment with gravity. However, this study shows that the accuracy and reproducibility of the FZ3D bullet trajectory tools to be comparable with previous research studies. [ABSTRACT FROM AUTHOR]

The susceptibility for recreational shooters to transfer gunshot residue (GSR) to both the interior and exterior of a vehicle is investigated. A comprehensive sampling protocol was used to assess the most likely areas of GSR transfer from recreational shooter contact, such as the steering wheel and the area, the firearms were stored (the trunk). Up to 315 characteristic GSR, particles were found in several locations throughout the interior of a vehicle. As many as 876 characteristic particles were found throughout a single vehicle. The data indicate that vehicles frequently occupied by firearms users are a potential source for inadvertent transfer of GSR to persons unrelated to firearm activity. In criminal cases where vehicles have been used, such transfer processes for GSR need to be considered within the context of any case interpretation. The implications for subsequent contamination and transfer processes from such vehicles require further investigation. [ABSTRACT FROM AUTHOR]

In order to assess the efficacy of vacuum metal deposition (VMD) as a technique to develop fingermarks on ballistic metallic surfaces, a preliminary study using six donors (three male & three female) was conducted. Using a sequential metal deposition process, two metal combinations were studied—gold/zinc and silver/zinc. Results indicate the potential of this technique, by developing identifiable fingermarks on brass metal disks aged from a few days up to more than a month old. As the development of fingermarks on fired (brass) cartridge cases is an area of interest, a further study was conducted where a total of 20 fingermarks were deposited on cases. After firing, second level fingermark characteristics were successfully observed on cartridge cases highlighting its potential as a fingermark enhancement method for ballistic brass materials. Further work is required to fully evaluate the VMD process and its reliability as a fingermark enhancing method on ballistic surfaces. [ABSTRACT FROM AUTHOR]

The appearance of new projectile propulsion modes is viewed as an important element for understanding human behaviour during the Palaeolithic. Because the organic components of hunting weapons (the bow, spear‐thrower and arrow, and spear shaft) are only rarely preserved archaeologically, some effort has been invested in experiments to explore how the projecting modes could be identified through the analysis of stone points. The kinetic energy developed by each mode of propulsion has been considered a key variable in these experiments. However, the data used in these studies generally come from a few ballistic studies, with varied results. We present the results of a systematic study conducted with a ballistic pendulum and combined with a classic ballistic analysis. We quantified and compared the kinetic energy developed by the four standard modes of propulsion known for the Palaeolithic. The kinetic energy values that we attained, especially those measured for thrusting spears, clearly differ from what has been assumed up to now, and thus challenge current models on the evolution of hunting technology. [ABSTRACT FROM AUTHOR]

Studies on ballistic trauma to the ribs and thorax, cranium, and long bones demonstrate the potential of obtaining a bullet caliber from an entrance wound. In order to validate prior research on caliber estimation in bone tissue and assess the viability of bullet type determination based on the macroscopic evidence at the entrance wound, thirty fleshed pork (Sus scrofa) shoulders (humeri) were shot with either lead or copper jacketed bullets in one of three calibers; 0.22, 9 mm, or 0.38. Overall, our findings are consistent with previous research indicating that calibers can be grouped into "small" and "large" categories. Bullet type, lead or copper jacket, can be ascertained based on cortical flaking and the analysis of materials deposited around the entry wound. The addition of this evidence holds value in cases where no firearm or ballistic evidence is recovered from a crime scene. [ABSTRACT FROM AUTHOR]

A bystander claimed to have been shot by a police officer, and CT scans were used to match qualitative and quantitative aspects of the unremoved bullet with police issued 9 mm Luger ammunition. CT scan methodology proved a valid approach for the measurement of bullets based on calculated measurement capability and correlation with "gold standard" physical measurement by vernier caliper. Measurements regarding length and base diameter, as well as length/diameter ratio, were insufficient to unambiguously identify a specific caliber, or a bullet of specific mass within a caliber class. It was, however, possible to exclude a bullet of specific design and mass with well‐characterized precision and accuracy values under selected CT scan conditions. A 9 mm Luger bullet (115 gr FMJ RN) was excluded from involvement in a shooting based on qualitative bullet shape combined with length, base, and ratio measurements of the bullet in‐situ for the victim. [ABSTRACT FROM AUTHOR]

Factors influencing effectiveness of automated comparisons, test‐fired bullets, and cartridge cases from 0.38 Special revolvers were logged into the Evofinder® Ballistic ID System. Tests were performed as follows: First test correlated test‐fires of the same type, second test compared different types of ammunition components, third test replicated the second test in a larger database, and fourth test replicated the third test with students having no previous firearm identification experience. System effectiveness with projectiles in the first test was 0.89. With cartridge cases, effectiveness was 0.79 with combined results, but analysis of separate results by breech face and firing pin revealed low effectiveness by breech face (0.40). In the second, third, and fourth tests, effectiveness with projectiles were 0.61, 0.51, and 0.44. In addition, these tests had effectiveness with cartridge cases equivalent to 0.55, 0.43, and 0.44. Results are useful to establish routine protocols, system improvements, or comparative assessment of other electronic systems. [ABSTRACT FROM AUTHOR]

Abstract: Three‐dimensional (3D) technologies contribute greatly to bullet trajectory analysis and shooting reconstruction. There are few papers which address the errors associated with utilizing laser scanning for bullet trajectory documentation. This study examined the accuracy and precision of laser scanning for documenting trajectory rods in drywall for angles between 25° and 90°. The inherent error range of 0.02°–2.10° was noted while the overall error for laser scanning ranged between 0.04° and 1.98°. The inter‐ and intraobserver errors for trajectory rod placement and virtual trajectory marking showed that the range of variation for rod placement was between 0.1°–1° in drywall and 0.05°–0.5° in plywood. Virtual trajectory marking accuracy tests showed that 75% of data values were below 0.91° and 0.61° on azimuth and vertical angles, respectively. In conclusion, many contributing factors affect bullet trajectory analysis, and the use of 3D technologies can aid in reduction of errors associated with documentation. [ABSTRACT FROM AUTHOR]

Abstract: Ballistic gelatin as simulant of the human body and organs is a support in forensics. After having obtained very good results for a new gelatin‐based composite in terms of physicochemical and rheological properties, this study focused on this material's mechanical behavior during stabbing and shooting versus bovine and porcine organs and standard ballistic gelatin. The hybrid gelatin has a predominantly elastic behavior at 23°C, whereas the elastic modulus becomes practically constant in the 10–0.1 Hz frequency range. In terms of stabbing behavior, the small variations obtained between porcine organs and surrogate are below 5%, the perforation indicating a good similarity. From the ballistic test results using 10 × 28T rubber balls, it has been seen that the hybrid ballistic gelatin conducts to more reliable and reproducible values of perforation/penetration versus standard gelatin, making from it a real candidate for use in forensic tests. [ABSTRACT FROM AUTHOR]

This ballistics study examines whether saline breast implants can decrease tissue penetration in firearm injuries. We hypothesize that the fluid column within a saline breast implant can alter bullet velocity and/or bullet pattern of mushrooming. The two experimental groups included saline implants with 7.4 cm projection and a no implant group. The experimental design allowed the bullet to pass-through an implant and into ballistics gel (n = 10) or into ballistics gel without passage through an implant (n = 11). Shots that passed through an implant had 20.6% decreased penetration distance when compared to shots that did not pass-through an implant; this difference was statistically significant (31.9 cm vs. 40.2 cm, p < 0.001). Implant group bullets mushroomed prior to gel entry, but the no implant group mushroomed within the gel. Bullet passage through a saline breast implant results in direct bullet velocity reduction and earlier bullet mushrooming; this causes significantly decreased ballistics gel penetration. [ABSTRACT FROM AUTHOR]

A review of the literature concerning the fate and behavior of gunshot residue ( GSR) is presented. A number of concomitant parameters including firearm and ammunition type, plume and GSR material characteristics, travel distances, chemical composition and GSR morphology are critically discussed in relation to their effects on the distribution and deposition, transfer and persistence processes of GSR. The underlying mechanisms associated with such processes are also considered. Knowledge of these processes on GSR materials could provide valuable information concerning scene preservation and subsequent forensic sampling. The number of GSR particles deposited can vary significantly with each firearm discharge, highlighting the potential to produce distinctive data in each individual case. With the continual development and compositional changes of new ammunition types, further evaluation of the effect these processes may have on GSR evidence and their possible influence on the interpretation of the analytical results should be given due consideration. [ABSTRACT FROM AUTHOR]

ABSTRACT What is violence? This article explores conceptions of violence from the perspective of scientists engaged in weapons research. Ballistics scientists are routinely excluded from the 'violent' label on grounds of class, status, education, and emotional comportment. The article analyzes the science of ballistics through the lenses of ethics and emotions. How do scientists justify experiments in ballistics, or the science of designing weapons and other technologies aimed at destroying environments and inflicting wounds (often fatal) and other forms of injury on people and nonhuman animals? In stark contrast to those who analyze weapons development as an objective science and who impart violent agency to autonomous technologies, I situate wound ballistics as a branch of applied moral philosophy. Its practice always involves an 'ought.' Although the central job of ballistics scientists is the 'effective production of wounds,' this is not regarded as violent, except by their victims, of course. In part, this lacuna is due to an ideological relationship forged between 'violence' and particular emotional states. It is also part of a political project defining 'the human.' [ABSTRACT FROM AUTHOR]

Damage produced by high-speed projectiles on organic tissue will depend on the physical properties of the tissues. Conditioning organic tissue samples to human core body temperature (37°C) prior to conducting ballistic experiments enables their behavior to closely mimic that of living tissues. To minimize autolytic changes after death, the tissues are refrigerated soon after their removal from the body and re-heated to 37°C prior to testing. This research investigates whether heating 50-mm-cube samples of porcine liver, kidney, and heart to 37°C for varying durations (maximum 7 h) can affect the penetration response of a high-speed, steel sphere projectile. Longer conditioning times for heart and liver resulted in a slight loss of velocity/energy of the projectile, but the reverse effect occurred for the kidney. Possible reasons for these trends include autolytic changes causing softening (heart and liver) and dehydration causing an increase in density (kidney). [ABSTRACT FROM AUTHOR]

Ballistic imaging systems can help solve crimes by comparing images of cartridge cases, which are recovered from a crime scene or test-fired from a gun, to a database of images obtained from past crime scenes. Many U.S. municipalities lack the resources to process all of their cartridge cases. Using data from Stockton, CA, we analyze two problems: how to allocate limited capacity to maximize the number of cartridge cases that generate at least one hit, and how to prioritize the cartridge cases that are processed to maximize the usefulness (i.e., obtained before the corresponding criminal case is closed) of hits. The number of hits can be significantly increased by prioritizing crime scene evidence over test-fires, and by ranking calibers by their hit probability and processing only the higher ranking calibers. We also estimate that last-come first-served increases the proportion of hits that are useful by only 0.05 relative to first-come first-served. [ABSTRACT FROM AUTHOR]

Projectile components that are traditionally radiolucent can be of considerable importance in determination of weapon type and caliber, but they are often missed on evaluation of postmortem radiographs. We hypothesized that these components would be significantly better visualized by evaluation of computed tomography (CT) scans compared to the practice standard of radiography alone. In this project, potentially radiolucent projectile components were both pulled apart and fired, and the radiolucent components were recovered. These components were embedded in blocks of ballistics gelatin and were imaged using both radiography and CT. The scans were evaluated by three blinded, board‐certified radiologists for the presence/absence of projectile components and true‐negative regions in each block. If a radiologist indicated visualization of a projectile component, they were further requested to describe their observation. It was found that traditionally radiolucent projectile components are not significantly more often identified on CT scans than radiography (p < 0.05). [ABSTRACT FROM AUTHOR]

The micro‐motion feature extraction of precession target is an effective way for discriminating warhead from decoy in missile ballistic defence. Generally, traditional methods based on high‐resolution range profile (HRRP) sequences put forward high requirements on modulation bandwidth for the system, increasing the complexity of the system significantly. Utilising single‐frequency ladar without modulation, the authors proposed a precession parameter extraction algorithm of precession target based on high‐resolution Doppler profile (HRDP) sequences. Firstly, they model the Doppler bandwidth of the cone‐shaped precession target with the observation angle. Under the assuming that the measurement error obeys zero‐mean Gaussian distribution, the probability density function of Doppler bandwidth is established. Then, the precession parameters are estimated with measured Doppler profile sequences through maximum likelihood estimation method. Compared with the methods based on HRRPs, the proposed method based on the Doppler profile has lower requirements on the system and easier to implement. Laboratorial data has been used to validate the feasibility of the proposed method. [ABSTRACT FROM AUTHOR]

Micro‐Doppler (mD) characteristics of the ballistic targets have attracted great attention due to the potential in target discrimination. However, current investigations mainly focus on blunt‐nosed cone and cone‐cylinder‐shaped targets. In practical applications, ballistic targets are always designed as the streamlined shape due to smaller aerodynamic resistance and lower detectability. In this Letter, the mD characteristics of streamlined ballistic targets are analysed. Owing to the unique mD signatures, the sliding scattering centre induced by the reflection from the streamlined curved surface is particularly focused. Finally, simulation results via the electromagnetic computation verify the correctness of the analysis. [ABSTRACT FROM AUTHOR]

With the aim of providing better control of shooting experiments performed with replicas of prehistoric projectiles, we have conducted an instrumental archaeology study on the efficiency of prehistoric projectile points by placing emphasis on their adhesion and ballistic characteristics. In order to avoid any reproducibility problems, hafting adhesives were made with controlled mixtures of commercial rosin (also called 'colophany') and beeswax added as a plasticizer. An original experimental device has been developed to instrument a bow, allowing the control of both the trajectories and the velocities of the different shoots. In the course of an experimental programme on Sauveterrian microliths from the Mesolithic period of the South of France, the experimental system was applied to composite replica projectile tips of Mesolithic hunters. Arrows being shot at transparent targets were filmed in order to evaluate the penetration length and residual damage. Interestingly, this study reveals that the properties of the mixture are highly dependent on the velocity of the arrows. It was shown that-contrary to previous experiments that usually used a mixture in which rosin predominates- the most efficient adhesive is made of 70 wt% beeswax with only 30 wt% rosin. This result is of great importance for improving further shooting experiments and overcoming the problems frequently mentioned due to the loss of the flint armatures before they reach the animal target, or at least before penetration. When using this appropriate mixture, the lateral armatures are resistant to most of the shots. Experiments performed on real boars' flesh have also shown that the presence of lateral microliths allows the laceration inflicted on the target to be enlarged. Finally, a critical parameter has been identified, which is the location on the arrow of the microlithic element. [ABSTRACT FROM AUTHOR]

Automated firearms identification ( AFI) systems contribute to shedding light on criminal events by comparison between different pieces of evidence on cartridge cases and bullets and by matching similar ones that were fired from the same firearm. Ballistic evidence can be rapidly analyzed and classified by means of an automatic image analysis and identification system. In addition, it can be used to narrow the range of possible matching evidence. In this study conducted on the cartridges ejected from the examined pistol, three imaging areas, namely the firing pin impression, capsule traces, and the intersection of these traces, were compared automatically using the image analysis and identification system through the correlation ranking method to determine the numeric values that indicate the significance of the similarities. These numerical features that signify the similarities and differences between pistol makes and models can be used in groupings to make a distinction between makes and models of pistols. [ABSTRACT FROM AUTHOR]

Making intertemporal choices (choosing between rewards available at different points in time) requires determining and comparing the subjective values of available rewards. Several studies have found converging evidence identifying the neural systems that encode subjective value in intertemporal choice. However, the neural mechanisms responsible for the process that produces intertemporal decisions on the basis of subjective values have not been investigated. Using model-based and connectivity analyses of functional magnetic resonance imaging data, we investigated the neural mechanisms underlying the value-accumulation process by which subjective value guides intertemporal decisions. Our results show that the dorsomedial frontal cortex, bilateral posterior parietal cortex, and bilateral lateral prefrontal cortex are all involved in the accumulation of subjective value for the purpose of action selection. Our findings establish a mechanistic framework for understanding frontoparietal contributions to intertemporal choice and suggest that value-accumulation processes in the frontoparietal cortex may be a general mechanism for value-based choice. [ABSTRACT FROM AUTHOR]

The field of forensic injury biomechanics is an emerging field. Biomechanically validated tools may assist interdisciplinary teams of investigators in assessing mechanisms of blunt head trauma resulting in skull fractures. The objective of this study is to assess the biofidelity of spherical, frangible skull-brain ( SB) surrogates. Blunt impacts were conducted at 20 m/s, using an instrumented 103 g rigid impactor, to the temporo-parietal region of four defleshed cephalic postmortem human subjects ( PMHS). Force-deformation response, fracture tolerance, and fracture patterns were recorded for comparison to spherical skull-brain surrogates. Three brain substitutes were assessed: 10% gelatin, lead shot with Styrofoam and water. Force-deformation response of the skull-brain surrogates was similar to defleshed PMHS up to the point of fracture; however, none of the surrogates fractured at tolerance levels comparable to the PMHS. Fracture patterns of the skull-brain surrogates were linear and radiating, while PMHS fractures were all depressed, comminuted. [ABSTRACT FROM AUTHOR]

ABSTRACT The purpose of this review is to introduce the interested reader to the literature on the use of silica glasses in ballistic applications. These applications include optically transparent windows (where their amorphous nature, appropriate band gap, and cheapness make them ideal window materials) as well as layers in opaque armours designed to be resistant to shaped charges. In the latter application, their increase in volume (bulking) on fracture disrupts the shaped charge jet. Other topics covered in this review include low-velocity damage by windborne debris, liquid and solid impact, dynamic methods of testing (Hopkinson pressure bar, Taylor impact, and plate impact shock loading), and constitutive models. The use of glass as a shaped charge is also discussed. [ABSTRACT FROM AUTHOR]

A series of ballistic impact experiments were conducted against a borosilicate glass (Borofloat®33) bonded to a polycarbonate substrate. Two of the objectives of the experiments were to measure crack velocities in the glass, and to measure the damage velocity in the glass. The speed of distinct propagating cracks was found to be 1.92 ± 0.03 km/s, independent of impact velocity. The maximum rate of damage propagation was found to be a function of impact velocity, but the damage velocity plateaued at 2.07 ± 0.04 km/s. [ABSTRACT FROM AUTHOR]

A numerical simulation of heat conduction in a grain aggregate is carried out to determine the packing fraction (the spatial fraction occupied by grains or 1-porosity) dependence of the thermal conductivity of the aggregate. Arrangements of grains are given by random ballistic deposition. It is found that the packing fraction dependence is well approximated by an exponential function. The number of contacts between grains is the crucial quantity in the conduction, and its packing fraction dependence is exponential. Heat conduction is found to be anisotropic, where the conduction along the deposition direction is more efficient than that perpendicular to the deposition direction. [ABSTRACT FROM AUTHOR]

Contrary to the moderate ballistic advantage of Al2 O3 ceramics over MgAl2 O4 polycrystals, the present study shows a reverse ratio of the ballistic strength of alumina and spinel single crystals: Spinel single crystals outperform sapphire and exhibit a similarly high stability as submicrometer Al2 O3 ceramics. The results correlate with different cleavage of single crystalline spinel and sapphire, changing the fragmentation on ballistic impact. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This paper presents an experimental and finite-element investigation of ballistic limit of thin single and layered aluminium target plates. Blunt-, ogive- and hemispherical-nosed steel projectiles of 19 mm diameter were impacted on single and layered aluminium target plates of thicknesses 0.5, 0.71, 1.0, 1.5, 2.0, 2.5 and 3 mm with the help of a pressure gun to obtain the ballistic limit in each case. The ballistic limit of target plate was found to be considerably affected by the projectile nose shape. Thin monolithic target plates as well as layered in-contact plates offered lowest ballistic resistance against the impact of ogive-nosed projectiles. Thicker monolithic plates on the other hand, offered lowest resistance against the impact of blunt-nosed projectiles. The ballistic resistance of the layered targets decreased with increase in the number of layers for constant overall target thickness. Axi-symmetric numerical simulations were performed with ABAQUS/Explicit to compare the numerical predictions with experiments. 3D numerical simulations were also performed for single plate of 1.0 mm thickness and two layered plate of 0.5 mm thickness impacted by blunt-, ogive- and hemispherical-nosed projectiles. Good agreement was found between the numerical simulations and experiments. 3D numerical simulations accurately predicted the failure mode of target plates. [ABSTRACT FROM AUTHOR]

A comprehensive review of the scientific literature on gunshot residue (GSR) is presented. Aspects of both inorganic and organic GSR are discussed, from formation and distribution, to sample collection, preparation, and analysis using a variety of techniques. The interpretation of GSR results is also considered including issues surrounding the contamination, distribution, and transfer of GSR. Potential problems with ulterior sources of GSR like particles have been reported in the literature. For example, particles from environmental and occupational sources have been highlighted as exhibiting similar chemical and morphological characteristics to GSR. These findings are put into context with regard to interpreting samples. A move toward a “case by case” approach is argued to be more preferable to a “formal” classification system where possible. The analysis of both inorganic and organic compositions of residue samples as well as morphological considerations is considered to be a more ideal approach to GSR analysis, whereever practicable. [ABSTRACT FROM AUTHOR]

Pork ribs with intact muscle tissue were used in an experimental attempt to identify bullet wipe on bone at distances from 1 to 6 feet with 0.45 caliber, full metal jacket ammunition. This resulted in the unexpected finding of primer-derived gunshot residue (GSR) deep within the wound tract. Of significance is the fact that the GSR was deposited on the bone, under the periosteum, after the bullet passed through a Ziploc® bag and c. 1 inch of muscle tissue. It is also important to note that the GSR persisted on the bone after the periosteum was forcibly removed. The presence of primer-derived GSR on bone provides the potential to differentiate gunshot trauma from blunt trauma when the bone presents an atypical gunshot wound. In this study, the presence of gunshot primer residue at a distance of 6 feet demonstrates the potential for establishing maximum gun-to-target distance for remote shootings. [ABSTRACT FROM AUTHOR]

Home-made guns are imitations of typical firearms and usually have handgun characteristics. This article presents an unusual case of a suicide carried out by means of a fatal gunshot wound to the head using a home-made zip gun. A 49-year-old male, with a history of paranoid psychosis was found dead in the dwelling place of a family house. The investigation at the crime scene did not lead to suspicion of a gunshot wound because of the unusual nature of the firearm used. A medical examiner diagnosed an opened head injury as the primary cause of the victim’s death. The autopsy findings provided immediate grounds for further inspection of the crime scene. Subsequently, a simple zip gun, which had been overlooked during the scene investigation, was discovered. An undeformed projectile recovered from the victim’s head was consistent with the use of the home-made firearm. Following the completion of the investigations and autopsy, the death was classified as a suicide. [ABSTRACT FROM AUTHOR]

In case of gunshot deaths, atypical wounds can make the distinction between entrance and exit wounds harder. They may be due either to anatomical reasons or to diverse cogent ballistic arguments. The reported case pertains to a fatal hunting accident involving an expanded conical point bullet against the neck with both atypical entrance and exit wounds. Ballistic analyses including test firings allowed a better understanding of the external and internal findings. Upon premature impact with an intermediary target, the bullet experienced expansion in the formation of sharp brass petals responsible for a star-shaped entry wound. The trajectory of the deformed high energy projectile through the victim's body was then deviated by the cervical column, causing it to be tangential to the skin when exiting the body. The description of such atypical cases may benefit other experts and may assist in their investigation into similar cases. [ABSTRACT FROM AUTHOR]

In order to assess whether or not the class and individual characteristics of a firearm change over time, five different makes of Turkish self-loading pistol were tested and were each fired a large number of times. The class and individual characteristics were identified for each pistol and the first fired cartridge case was compared with the subsequent consecutive 250th fired cases for each pistol. It was found that there were slight changes in some of the individual and class characteristics; however, this was not statistically significant and did not affect the ability of the firearms examiner to match the first fired case to the last fired case for each firearm tested. [ABSTRACT FROM AUTHOR]

The Apulian (South of Italy) territory saw the birth of a criminal organization called Sacra Corona Unita (SCU, United Holy Crown) which transformed the rules of traditional mafia organizations. This work examined 83 victims of the SCU between 1980 and 2000. The bodies were mainly of SCU members and in some cases, of police and law enforcement officers and other citizens caught in the crossfire. Some of these were discovered; thanks to the collaboration of “repented” SCU members who became police informers. The condition of the bodies varied in relation to the date and manner of killing. In some cases anthropometric research methods were necessary. In 73% of the cases, lesions of the head were the only marks left on the body. In conclusion, the existence of some social aspects connected with the symbolisms and membership rites that characterized the origin, evolution, and decline of the SCU is stressed. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This study evaluates the abilities of the Integrated Ballistics Identification System (IBIS) and BulletTRAX-3D electronic imaging systems to identify bullets fired by the same weapon in a large database of images. Ten consecutively rifled handgun barrels were test fired to obtain reference sample and known match sample pairs for upload onto both bullet acquisition systems. Both copper-jacketed and lead bullets were uploaded, to account for variations in the manner in which markings are reproduced on the different metal compositions. Ranked correlation lists were examined and evaluated. For copper-jacketed bullet correlations, both IBIS and BulletTRAX-3D identified all reference samples to their known matches within the top 10 positions. For lead bullets, BulletTRAX-3D identified all reference samples to their known match in the top 10 positions while IBIS identified only 30%. For inter composition comparisons, BulletTRAX-3D was more successful than IBIS, identifying 100% of reference samples to their known match in the top 20 for copper-jacketed to lead comparisons and 90% for lead to copper-jacketed comparisons. These results suggest that BulletTRAX-3D is more effective than IBIS in the analysis of a wider range of bullet types and it was also found to produce images of superior quality. [ABSTRACT FROM AUTHOR]

An increasing number of projects have examined the perceptual magnitude of visible artifacts in animated motion. These studies have been performed using a mix of character types, from detailed human models to abstract geometric objects such as spheres. We explore the extent to which character morphology influences user sensitivity to errors in a fixed set of ballistic motions replicated on three different character types. We find user sensitivity responds to changes in error type or magnitude in a similar manner regardless of character type, but that users display a higher sensitivity to some types of errors when these errors are displayed on more human-like characters. Further investigation of those error types suggests that being able to observe a period of preparatory motion before the onset of ballistic motion may be important. However, we found no evidence to suggest that a mismatch between the preparatory phase and the resulting ballistic motion was responsible for the higher sensitivity to errors that was observed for the most humanlike character. [ABSTRACT FROM AUTHOR]

Lieutenant Colonel Robert Kenneth Wilson (1899–1969) was a surgeon who fought in both world wars and joined the Special Operations Executive parachuting behind enemy lines into Holland, France and Borneo, the last mission being with Australian forces (Semut II). He was an expert on firearms and gave opinion on ballistics at the Old Bailey during the 1930s. He also wrote a definitive text on automatic pistols with editions published in 1943 and 1975. He was an Edinburgh Fellow (1926), who had a practice in general surgery and gynaecology in Queen Anne Street during the 1930s. He took the famous 1934 ‘surgeon’s photo’ of the Loch Ness monster that was not admitted to be a hoax until 1994. After World War II, he became the first surgical specialist to work in the public service of the then Territory of Papua and New Guinea (1950–1956), where he wrote several papers on surgical topics. He married Gwen (1924), the daughter of Henrietta Gulliver, an Australian painter. They had two sons, Richard and Phillip. After practice he retired to Melbourne where he died of carcinoma oesophagus. [ABSTRACT FROM AUTHOR]

The Tucson Police Department, Tucson, AZ, has begun using the Polyshok Impact Reactive Projectile (IRP), a new type of shotgun ammunition that includes a lead bead core that travels within single, plastic-encased projectile. On impact, the core is released to distribute over a small area, thereby disintegrating on impact to reduce the likelihood of exit or collateral damage on missed shots. After a brief review of shotgun slug ballistics and wound characteristics and a discussion of the mechanism of the Polyshok IRP, we report the first death in the United States from this ammunition. Findings included a single entrance wound with plastic ammunition components and small lead particles recovered from the body, the combination of which normally would suggest a close-range shooting with birdshot. However, the characteristics of this ammunition create different patterns than are found with slugs or shot, so that a medical examiner unfamiliar with the Polyshok IRP could draw inaccurate conclusions about ammunition and range of fire. Because the single projectile fired from this ammunition is composed of both plastic and lead, plastic components are likely to be found within the wound at any range of fire, unlike traditional shot or slug ammunition. Also, the small size of lead particles found spread through the wound cavity would ordinarily suggest a small-size shot, whereas the external appearance of the wound (a single entrance with no dispersion of shot) and the pattern of tissue destruction are more consistent with the patterns of injury associated with shotgun slugs. [ABSTRACT FROM AUTHOR]

In Norway, Sweden, and Finland most beavers (Castor spp.) harvested are shot with center-fire rifles. Shooting entails problems not encountered in trapping including pelt damage from bullet holes (body shots are common) and escape of wounded animals. It was predicted that beavers shot in the body with splinter projectiles designed to fragment after impact would experience fewer exit holes (i.e., less pelt damage) and less wounding, but more meat loss, than those shot with conventional controlled expansion projectiles. Twenty-two hunters shot 163 beavers during normal hunting. As predicted, exit frequency was lower for splinter (22%) than controlled expansion projectiles (95%) but neither wounding frequency nor meat damage varied significantly. The combined wounding frequency for both projectile types was 4.3%. Ninety-eight percent of the body-shot animals retrieved (n = 111) appeared to die instantly. Beaver hunting with center-fire rifles was considered humane. [ABSTRACT FROM AUTHOR]

Presents the study of the technological innovations for less-lethal kinetic energy munitions used in law enforcement in the U.S. Examinations taken to determine energy per unit area required to penetrate various regions of the body; Used of eight unembalmed postmortem human specimens in the testing experiment; Evaluation on the conducted test results.