A comparison of gelatine surrogates for wound track assessment.

The use of ordnance gelatine has been widespread in the field of ballistics as a simulant for soft tissue when assessing ballistic threats. However, the traditional method of preparing ordnance gelatine is time-consuming and requires precision to ensure that the final mold meets the required specifications. Furthermore, temperature control is necessary post-production, and there are limitations on its usage duration. To address these issues, manufacturers have developed pre-mixed, gelatine-like products that are stable at room temperature and require less preparation time. Nonetheless, it is uncertain whether these new products can perform in the same manner as the gold standard of ordnance gelatine. This study used five types of blocks, including ordnance gelatine (10% and 20%), Clear Ballistics (10% and 20%) and Perma-Gel (10%) and subjected them to 9 mm, 0.380 Auto fired from a universal receiver and a 5.56 × 45 mm ammunition fired by a certified firearms instructor. Delta-V and total energy dissipation were measured after each test using data collected from ballistic chronographs placed in front of and behind each block. High-speed video was recorded, and a cut-down analysis conducted. The findings revealed variations in energy dissipation and fissure formation within the block, with greater energy based on fissure formation observed in the ordnance gelatine. Additionally, the high-speed video showed the occurrence of secondary combustions occurring in the premixed gelatines.

Skin simulants for wound ballistic investigation - an experimental study.

Gunshot wound analysis is an important part of medicolegal practice, in both autopsies and examinations of living persons. Well-established and studied simulants exist that exhibit both physical and biomechanical properties of soft-tissues and bones. Current research literature on ballistic wounds focuses on the biomechanical properties of skin simulants. In our extensive experimental study, we tested numerous synthetic and natural materials, regarding their macromorphological bullet impact characteristics, and compared these data with those from real bullet injuries gathered from medicolegal practice. Over thirty varieties of potential skin simulants were shot perpendicularly, and at 45°, at a distance of 10 m and 0.3 m, using full metal jacket (FMJ) projectiles (9 × 19 mm Luger). Simulants included ballistic gelatine at various concentrations, dental silicones with several degrees of hardness, alginates, latex, chamois leather, suture trainers for medical training purposes and various material compound models. In addition to complying to the general requirements for a synthetic simulant, results obtained from dental silicones shore hardness 70 (backed with 20 % by mass gelatine), were especially highly comparable to gunshot entry wounds in skin from real cases. Based on these results, particularly focusing on the macroscopically detectable criteria, we can strongly recommend dental silicone shore hardness 70 as a skin simulant for wound ballistics examinations.

Observing the fragmentation of two expanding bullet types and a full metal-jacketed bullet with computed tomography-a forensic ballistics case study.

Computed tomography (CT) may have a crucial role in the forensic documentation and analysis of firearm injuries. The aim of this forensic ballistics case study was to explore whether two types of expanding bullets and a full metal-jacketed bullet could be differentiated by inspecting bullet fragments and fragmentation pattern in CT. Three types of .30 caliber bullets (full metal-jacketed Norma Jaktmatch, expanding full-copper Norma Ecostrike, and expanding soft-point Norma Oryx) were test fired from a distance of 5 m to blocks of 10% ballistic gelatine. CT scans of the blocks were obtained with clinical equipment and metal artifact reduction. Radiopaque fragments were identified and fragmentation parameters were obtained from the scans (total number of fragments, maximum diameter of the largest fragment, distance between entrance and the closest fragment, length of the fragment cloud, and maximum diameters of the fragment cloud). The fragmentation patterns were additionally visualized by means of 3D reconstruction. In CT, the bullet types differed in several fragmentation parameters. While the expanding full-copper bullet Ecostrike left behind only a single fragment near the end of the bullet channel, the soft-point Oryx had hundreds of fragments deposited throughout the channel. For both expanding bullets Ecostrike and Oryx, the fragments were clearly smaller than those left behind by the full metal-jacketed Jaktmatch. This was surprising as the full metal-jacketed bullet was expected to remain intact. The fragment cloud of Jaktmatch had similar mediolateral and superoinferior diameters to that of Oryx; however, fragments were deposited in the second half of the gelatine block, and not throughout the block. This case study provides a basis and potential methodology for further experiments. The findings are expected to benefit forensic practitioners with limited background information on gunshot injury cases, for example, those that involve several potential firearms or atypical gunshot wounds. The findings may prove beneficial for both human and wildlife forensics.

New alginate-gelatine method for casting of staining inside firearm barrels.

Contact shots to the head often leave behind biological traces inside firearm barrels, a phenomenon of great forensic interest. Until now, the visualization and preservation of these traces presented a significant challenge, lacking a reliable method. This study addresses this gap by searching for a suitable method to extract the traces within a casting. Using alginate or gelatine as suitable materials, the results were hampered by serious adhesion issues and their extraction out of the firearm barrel was impeded. Finally, the combination of 11% gelatine with 1% alginate, introduced into the barrel around a 'central spine', succeeded to consistently produce replicable castings. Experimental contact shots displayed a distinct staining gradient from the muzzle to the rear of the barrel, as revealed through endoscopy and proved in the macroscopic casting. The technique proved effective for various common handgun barrels and successfully preserved blood and gunshot residue (GSR) patterns within the barrel. This method offers the dual benefits of visually mapping staining patterns and securing localized samples for targeted molecular genetic analysis in forensic investigations.

Terminal ballistics performance of 9 × 19 mm cartridges in 10% ballistic gelatin: FBI Protocol based analysis of Brazilian-made law enforcement ammunition.

PURPOSE: Understanding that a projectile entering the human body can cause damage or destruction to live tissues through a variety of wounding mechanisms - permanent cavity, temporary cavity, and fragmentation - is crucial for researching terminal ballistics and understand the patterns of gunshot wound configuration. METHODS: The present work tested four different types of ammunition in caliber 9 × 19 mm (Full Metal Jacketed, Gold Hex, Copper Bullet Tactical and Bonded), using ballistic gelatin at 10% as soft tissue surrogate. The tests were based on the Federal Bureau of Investigation Protocol and included shots through bare gelatin, heavy clothing, plywood, steel sheets and auto glass. As a comparison parameter, the American-made Federal™ HST, used by several law enforcement agencies in the USA, was also tested in the same conditions. RESULTS: The Full Metal Jacketed cartridge had a uniform performance throughout the experiment, showing high penetration levels and no expansion, as expected. Gold Hex demonstrated a strong tendency to fragment with low levels of penetration and weight retention. Copper Bullet Tactical did not achieve the 12" minimum penetration in the soft barrier phases but expanded aggressively. Finally, Bonded only failed to achieve the 12" mark of penetration in phase 5 (auto glass), the hardest barrier in the whole Protocol. Tested for comparison purposes, Federal HST showed aggressive expansion in the initial phases (over 100%), after surpassing the 12" threshold. CONCLUSION: The study concluded that heavier projectiles (CBC Bonded and Federal HST) performed better than lighter and faster bullets in terms of terminal ballistics.

Gunshot residues found at the exit wound: a case report.

Gunshot residues (GSRs) play an important role in forensic investigations of gun-related violence. The presence of GSRs has been described to help to identify the bullet entry area, as it was supposed not to be found at exit wounds. This report details the suicidal headshot of an 84-year-old male where unburned tube-like, cuboid and flake-formed powder particles have been found not only at the inside of the muzzle but also circular around the exit wound. With very short-barrelled weapons, it must be expected that part of the propellant charge leaves the barrel unburned behind the bullet. In contrast to that, the barrel length of the used weapon should lead to a complete burn-up of powder particles. The surprisingly large number of unburned powder particles present at the exit wound of the injury gave reason for further investigation to understand the underlying ballistic aspects and outlines the importance of having a close look at incidence scene photos during an investigation.

Gunshots through laminated glass: expelled compounded fragments as a function of bullet type.

In the frame of an experimental setting, the formation of round-shaped compounded glass fragments on the exit site after gunshots through a windshield was examined. For that purpose, a 9 × 19 mm pistol (HK P30) and two different cartridges containing (a) a full metal jacketed round-nosed projectile and (b) a deformation projectile were used. On the basis of 52 gunshots, the morphology, impact angles and terminal ballistics of occurring compounded glass fragments were examined. The results showed that the compounded glass fragments' morphology allowed for the differentiation of two used projectiles. Fragments were able to cause round-shaped defects in a single cotton layer (T-shirt) with subsequent penetration of up to 2.4 cm into ballistic gelatin (10%, 4 °C). As a function of the projectile type, the compounded glass fragments showed different reproducible impact angles that differed notably from the known conical pattern of expelled glass fragments after bullet penetration. These findings might help to explain the atypical morphology of gunshot wounds with laminated glass as an intermediate target and prevent possible misinterpretations when reconstructing the sequence of events.

Skin laceration caused by a short distance shot from a pepper spray launcher: a case report.

Pepper spray launchers are more precise and wind stable compared to conventional pepper sprays and are commonly used as a self-defensive tool. With the advanced potential, they may also harbour a greater risk for injuries, especially if they are not used within the suggested safety distance. If the shooting distance is below 1.5 m, energy densities may exceed the threshold energy density for the penetration of skin leading to skin laceration. We present a case where a man is hit by the liquid jet of a JPX Jet Protector® with an estimated shooting distance of 0.3 m. The man suffered from a bleeding skin laceration, which had to be sewed in the hospital. This case report furthermore outlines the potentially dangerous effect of pepper spray launchers and thereby their role in forensic investigations.

Modeling of Ammunition Dynamic Pressure Measurement Chain in Ballistic Tests.

The use of piezoelectric transducers for internal dynamic pressure measurements in ammunition testing provides a significant advantage in the development and performance analysis of weapons and ammunition. Knowledge of the electrical characteristics of the dynamic pressure measurement chain, which includes the piezoelectric transducer and the charge amplifier, is a relevant condition for the design of interior ballistics pressure measurement systems. Thus, this study aims to characterize and model a piezoelectric transducer and its associated charge amplifier. First, the piezoelectric transducer was characterized using impedance analysis and modeled using a least squares curve-fitting tool, according to the Butterworth-Van Dyke model. Next, the charge amplifier was characterized through response analysis based on known inputs and modeled using LTSpice simulation techniques and the least squares curve-fit tool. Consequently, a measurement chain model is presented and simulated for two cases with different impulse signals. The first impulse signal was obtained from an interior ballistics computer simulation, and in the second case, it was considered the negative step signal characteristic of the calibration of piezoelectric transducers by means of dead weight. From the simulations, it was possible to verify the effectiveness of the model, which provided results with a low error in relation to the original pressure curve, and its applicability is demonstrated by the result of the simulation of the pressure variation in the calibration, where the attenuation of the signal can be visualized as the characteristic of the input curve changes.

Bursting of the upper jaw prosthesis and fractures of the lower jaw as indirect injury pattern caused by a headshot: a case report.

Gunshots to the human body can cause direct and indirect injuries. Direct injuries are a consequence of the projectile guiding its way through the body, creating a permanent wound channel and thereby damaging the penetrated as well as the adjacent tissue. In addition, the temporary wound cavity is responsible for indirect injuries occurring distant to the actual wound tract. This can potentially affect different types of tissue, like blood vessels, organs, or bones, that are not directly passed through by the projectile. For this case report, we describe a suicidal headshot to the temporal area where the extension of the temporary wound cavity and its subsequent collapse led to massive energy transfer to the surrounding tissue leading to breakage of the upper dental prosthesis and fractures of the lower jaw. Thereby outlining the ballistic mechanisms causing indirect injury pattern that have to be considered when examining gunshot wounds.

Semi-computational approach for assessing the damage to human soft tissues: the case of FMJRN versus HP-XTP 9 mm bullet penetration in ballistic soap.

Ballistic soap blocks are used in wound ballistics to assess the potential damage of the ammunition employed, allowing observation of the energy transfer occurred along the wound channel. The density and viscosity of ballistic soap (also called tissue simulant) simulate, to a good degree of approximation, the effect resulting from the interaction of penetrating bullets with living human soft tissue. Ballistic soap has a "plastic reaction" to bullet penetration, and therefore, unlike ballistic gelatin, the expansion of temporary cavity remains imprinted in the tissue simulant. When the soap blocks are sectioned or divided with nondestructive instrumental techniques (e.g., Compton's scattering tomography), it's possible, therefore, to observe the temporary cavity determined by the penetration of the bullet. This study provides insight into the severity of injuries originated from two different types of bullets of the same caliber by employing ballistic soap as a tissue simulant. In addition, it provides guidance to forensic practitioners on the proper use of ballistic soap for simulating gunshot wounds. The semi-computational approach employed, based on the results obtained from the firing tests, allowed the authors to understand that there is likely a threshold value of projectile energy density, close to 1 J/mm2, beyond which its penetration into the ballistic soap ceases.

Two case reports of fatal injuries sustained from tear gas guns loaded with pebbles as missiles.

These two case reports are of fatal injuries from less-lethal weapons (tear gas guns) using pebbles as an unconventional ammunition. Reported here are the fatal outcomes of two 19-year-old males, one with head trauma and the other with abdominal trauma. They were admitted to the ED and subjected to immediate exploratory operations, but they passed away. On autopsy, the first case demonstrated a right frontal bone fracture with subdural hemorrhage and a 3 × 2.5 cm pebble retained in the skull. The second case showed severe liver laceration in close vicinity to a cubical pebble (3.2 × 3 cm). The mechanical forces involved in skull fracture and autopsy are discussed. In the current cases, the relatively larger weight and size together with the surface configuration of the pebble projectile were the main influential factors that contributed to the severity of damage and fatality.These case reports are a working example of the effect of the mass of projectiles in increasing the power of penetration. The direct shooting to the head and the abdomen together with the misuse of these weapons are capable of inflicting fatal injuries.

Surface wave analysis of the skin for penetrating and non-penetrating projectile impact in porcine legs.

Secondary blast injuries may result from high-velocity projectile fragments which ultimately increase medical costs, reduce active work time, and decrease quality of life. The role of skin penetration requires more investigation in energy absorption and surface mechanics for implementation in computational ballistic models. High-speed ballistic penetration studies have not considered penetrating and non-penetrating biomechanical properties of the skin, including radial wave displacement, resultant surface wave speed, or projectile material influence. A helium-pressurized launcher was used to accelerate 3/8″ (9.525 mm) diameter spherical projectiles toward seventeen whole porcine legs from seven pigs (39.53 ± 7.28 kg) at projectile velocities below and above V50. Projectiles included a mix of materials: stainless steel (n = 26), Si3N4 (n = 24), and acetal plastic (n = 24). Tracker video analysis software was used to determine projectile velocity at impact from the perpendicular view and motion of the tissue displacement wave from the in-line view. Average radial wave displacement and surface wave speed were calculated for each projectile material and categorized by penetrating or non-penetrating impacts. Two-sample t-tests determined that non-penetrating projectiles resulted in significantly faster surface wave speeds in porcine skin for stainless steel (p = 0.002), plastic (p = 0.004), and Si3N4 ball bearings (p = 0.014), while ANOVA determined significant differences in radial wave displacement and surface wave speed between projectile materials. Surface wave speed was used to quantify mechanical properties of the skin including elastic modulus, shear modulus, and bulk modulus during ballistic impact, which may be implemented to simulate accurate deformation behavior in computational impact models.

[War wounds and ballistics]. / Plaies de guerre et balistique.

Ballistic wounds, which historically concerned military populations, now also affect civilian practice. Terrorist attacks, urban violence and certain accidents have brought them into the daily routine of some French hospitals. Their frequency fully justifies the need for every health-care professional to be aware of the major issues involved in their management. In this section, we will describe the various penetrating ballistic wounds and their specific features. We will also rectify certain preconceived ideas that should not be peddled by healthcare professionals, in order to maintain a high standard of care.

[Ballistic wound in the pre-hospital and emergency room: Damage Control Resuscitation]. / Plaies balistiques en préhospitalier et aux urgences : Damage Control Resuscitation.

Damage Control Resuscitation (DCR) is a strategy designed to prioritize hemostasis procedures, from the point of injury to surgical management, whether faced with an influx of bleeding casualties or a single casualty with severe hemodynamic instability. Widely disseminated, it provides clear objectives for prioritizing physiological restoration to the anatomy required for short-term survival. Initially applied to surgery, DCR has now been extended to the entire upstream care chain, including first aid and emergency medicine.

[Orthopedic ballistic injury, a five-beat waltz]. / Blessé balistique orthopédique, une valse à cinq temps.

Two-thirds of ballistic injuries result in severe limb damage. Damage Control Orthopaedic is a surgical strategy that makes it possible to save life, limb and function using simple mnemonic markers: 5minutes, 6hours, 7 days, 8 weeks and 9 months. The many players involved in this coherent care pathway, with its multiple surgical challenges, help to meet the challenge of comprehensive rehabilitation for orthopaedic ballistic injuries.

Droplet motions fill a periodic table.

Drawing parallels to the symmetry breaking of atomic orbitals used to explain the periodic table of chemical elements; here we introduce a periodic table of droplet motions, also based on symmetry breaking but guided by a recent droplet spectral theory. By this theory, higher droplet mode shapes are discovered and a wettability spectrometer is invented. Motions of a partially wetting liquid on a support have natural mode shapes, motions ordered by kinetic energy into the periodic table, each table characteristic of the spherical-cap drop volume and material parameters. For water on a support having a contact angle of about 60°, the first 35 predicted elements of the periodic table are discovered. Periodic tables are related one to another through symmetry breaking into a two-parameter family tree.

Low-velocity, civilian firearm extremity injuries-review and update for radiologists.

Firearm injuries are a preventable epidemic in the USA. Extremities are commonly affected in gunshot injuries. Such injuries may be complex with concomitant osseous, soft tissue, and neurovascular components. The maximum wounding potential of a projectile is determined by its kinetic energy and the proportion of the kinetic energy that is transmitted to the target. Accurate assessment of ballistic injuries is dependent on utilizing the principles of wound ballistics, accurate bullet count, and ballistic trajectory analysis. The goals of this article are to review wound ballistics and the imaging evaluation of extremity civilian firearm injuries in the adult population, with emphasis on ballistic trajectory analysis, specific ballistic fracture patterns, and diffuse, secondary soft tissue ballistic injuries.

Gunshot trauma in human long bones: towards practical diagnostic guidance for forensic anthropologists.

In contrast to cranial gunshot trauma, diagnosis and interpretation of gunshot trauma to long bones remains difficult and controversial. The aim of this study is to review the published literature on fracture patterns resulting from gunshot trauma in human long bones, and to use the described characteristics to provide practical guidance for the forensic anthropologist. In order to achieve this, medical and forensic publications on this topic were reviewed. Several types of fractures, such as linear, oblique, comminuted and butterfly fractures, have been observed in either the shaft or the ends of long bones. Indirect fractures that are not caused by bullets striking bone directly but by bullet-induced forces to the surrounding soft tissue have been found as well. Some of these fractures are related to a specific context or mechanism which might help in the forensic reconstruction of events. It is recommended that future research should focus on available medical data to provide more detailed descriptions on fracture patterns for forensic purposes. Experimentation with bone surrogates and computer modelling might also provide better and more realistic reconstructions of gunshot trauma in the future and provide valuable insights for its diagnosis and interpretation in forensic anthropology.

[Forensic examination of air gun dart wounds]. / Sudebno-meditsinskaya otsenka ranenii drotikami, metaemymi iz dukhovykh ruzhei.

The objective was to study the mechanism of formation of experimental wounds of the human body dummy by 12 different types of common air gun darts. The impact of dart tips design features on macro- and microscopic morphological patterns of wounds was established; the description of further laboratory diagnostics of the wounds was provided.