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.

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.

Ballistic long bone fracture pattern: an experimental study.

When dealing with badly preserved cadavers or skeletal human remains, the assessment of death circumstances remains challenging. When forensic evidence cannot be taken from the skin and soft tissue, the information may only be deduced from more resistant elements such as bone. Compared to cranial gunshot injuries, reliable data on ballistic long bone trauma remains scarce. This study aims to define ballistic fracture characteristics in human long bones. The shaft of 16 femurs and 13 humeri from body donors was perpendicularly shot with a 9-mm Luger full metal jacket bullet at an impact velocity of 360 m/s from a distance of 2 m. Some bones were embedded in Clear Ballistics Gel®, and some were shot without soft tissue simulant in order to better visualise the fracture propagation on the high-speed camera. The fractures were examined macroscopically and compared between the sample groups. We consistently found comminuted fractures with a stellate pattern. Fracture details were classified into entrance, exit and general characteristics. For some traits, we detected different occurrence values in the group comparison. The results indicate that some of the traits depend on bone properties such as shaft diameter, bone length and cortical thickness. The presence of ballistic gel also influenced some fracture traits, emphasising the relevance of soft tissue simulant in osseous gunshot experiments. This study revealed new insights in the detailed fracture pattern of human long bones. These may serve as guidelines for the identification and reconstruction of gunshot trauma in human long bones.

Review of non-penetrating ballistic testing techniques for protection assessment: From biological data to numerical and physical surrogates.

Human surrogates have long been employed to simulate human behaviour, beginning in the automotive industry and now widely used throughout the safety framework to estimate human injury during and after accidents and impacts. In the specific context of blunt ballistics, various methods have been developed to investigate wound injuries, including tissue simulants such as clays or gelatine ballistic, physical dummies and numerical models. However, all of these surrogate entities must be biofidelic, meaning they must accurately represent the biological properties of the human body. This paper provides an overview of physical and numerical surrogates developed specifically for blunt ballistic impacts, including their properties, use and applications. The focus is on their ability to accurately represent the human body in the context of blunt ballistic impact.

Extracorporeal bullet trajectory determination from scanned phantoms with bullet defects.

Shots with two different calibres (0.32 Auto and 9 mm Luger) were fired through phantoms that simulated human torsos, mounted on undercarriages with witness panels. The perforated phantoms were scanned with computed tomography (Siemens) using 80 kV and 140 kV and a slice thickness of 1 mm. The intracorporeal trajectories in the phantoms were compared to the known extracorporeal trajectories, derived from the perforations in witness panels. The discrepancy between the intracorporeal and extracorporeal trajectories, denoted as the absolute angle, was calculated for the trajectories before (front) and after (rear) the phantoms. Mean absolute angles at the front were lower than at the rear (2.27° vs. 4.54°) and the difference was statistically significant (p < 0.001). The results of the study imply that the line between the entrance and the exit wound in a scanned victim can be extended to the extracorporeal bullet trajectory leading towards the entrance wound. The absolute angles presented in this study give an impression of the expected errors with the two calibres. This can be helpful in shooting investigations to assess the position of the shooter from entrance and exit wounds in a scanned victim.

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.

[Features of coarse calico damage by hollow-point bullets of ammunitions to a 12-gauge fire smoothbore weapon (12×70) under the conditions of remote shooting distance]. / Osobennosti povrezhdeniya byazevoi tkani ekspansivnymi pulyami patronov k ognestrel'nomu gladkostvol'nomu oruzhiyu 12-go kalibra (12×70) v usloviyakh neblizkoi distantsii vystrela.

The article presents the experimental study results of damaged clothes imitators' (coarse calico) features in consequence of shot by ammunitions with hollow-point bullet from a 12-gauge fire smoothbore weapon (12×70). The generation mechanism of coarse calico damage during wound of underlying biological human body's imitator by bullet and the factors influencing on mentioned process have been clarified using high-speed video recording.

[Distribution features of gunshot residue from hunting Steyr Mannlicher AUG-Z3 carbine on targets]. / Osobennosti raspredeleniya na mishenyakh produktov vystrela iz okhotnich'ego karabina Steyr Mannlicher AUG-Z3.

OBJECTIVE: To study the morphology of distribution of shot factors on white targets made of coarse calico at different distances. MATERIAL AND METHODS: The study was conducted on 57 experimental damages of targets made of cotton fabric, caused by shots from hunting self-loading Steyr Mannlicher AUG-Z3 carbine of.223 Rem caliber. The number of experimental firings equal 19 was done by 3 shots at the distance from close range to 250 cm. The examination of shot targets was carried out using the visual, metric, stereoscopic (Leica 125M microscope) methods, in ultraviolet rays (LUMATEC SUPERLITE M Series light). RESULTS: The nature and morphology of distribution of gunshot residue on targets' surfaces made it possible to establish close range firing zones. The nature in which soot is deposited during shot under the conditions of point-blank range and in the first zone of close range (up to 8 cm) allows to establish the position of weapon's transverse plane relative to the target basing on a specific blowout of a gas-powder jet from special design of flame arrestor. The performed experimental shooting from hunting self-loading Steyr Mannlicher AUG-Z3 carbine made it possible to determine the metric and morphological characteristics of the close range firing zones: 1 zone is equal a distance up to 8 cm; 2 zone - up to 30 cm; 3 zone - up to 100 cm from muzzle of weapon. The design features of Steyr Mannlicher AUG-Z3 carbine's flame arrestor allow to identify the type of weapon according to the morphological pattern of target's damage. The complex of obtained data makes it possible to determine the firing distance with high accuracy.

Analysis of free-fall bullet injury potential in the cranium via finite elements method.

The aim of this study is to analyze the injury potential of the free-falling bullet in the cranium, which is known as a tired bullet in the public, with the finite element method (FEM) In the study, as penetrant 9 × 19 mm FMJ bullets with vertical falling angle, adult human skull and brain tissue were discussed. The results of the analysis with the Finite element method, which is similar to the cases reported before, revealed that free-falling bullets as a result of shooting into the air can cause fatal injuries.

Lethal head ballistic trauma with a «nonlethal¼ projectile: A case report and review of the literature.

Forensic investigations of cranioencephalic ballistic trauma involve several aspects, including the study of terminal ballistics. This includes the analysis of projectiles and the damage they cause. Although some projectiles are considered "non-lethal", serious injuries and deaths secondary to the use of this type of ammunition have been reported. We report the case of a 37-year-old man who died from ballistic head trauma after the use of "Gomm Cogne" ammunition. A post-mortem computed tomography (CT) showed a right temporal bone defect and seven foreign bodies. Three of these were located in the encephalic parenchyma, which showed diffuse hemorrhagic changes. External examination indicated that this was a contact entry wound and confirmed encephalic involvement. This case illustrates the potential lethality of this type of ammunition with CT and autopsy with similar features to single projectile firearm injuries.

[Impact of projectile incidence angle with obstacle during ricochet on the damage characteristics formed in smoothbore weapon shot]. / Vliyanie ugla vstrechi puli s pregradoi pri rikoshete na kharakteristiku povrezhdenii, obrazuyushchikhsya pri vystrele iz gladkostvol'nogo oruzhiya.

The aim of this study was to establish the degree of projectile incidence angle with obstacle on forensic medical characteristic of gunshot injuries arising from smoothbore weapon fire and bullet ricochet. Based on the comprehensive forensic study results of experimental entry gunshot injuries, statistically significant differences in the following morphological signs were found for two ranges of incidence angle values (10-20° and 30-50°): «Number of MD¼, «Length 1 MD¼, «Length 2 MD¼, «Width 1 MD¼, «Orientation of AD to the conventional clock face relative to MD 1 or to the group of largest MD (max. value)¼. The medians and limits of 99% confidence intervals of these features values were observed depending on the range of incidence angle values. The revealed patterns can be used in expert practice during forensic medical examination of gunshot injuries formed as a result of a projectile ricochet after smoothbore weapon fire, as well as to develop a methodology for conducting a forensic study of this gunshot injury type.

[Main milestones of forensic ballistics history in Russia]. / Osnovnye vekhi istorii sudebno-meditsinskoi ballistiki v Rossii.

The purpose of the scientific work is to outline the main stages of the development of forensic examination of gunshot injuries in Russia. The analysis of the special literature from 1865 to the present time has demonstrated that the issue of forensic examination of gunshot injuries has been analyzed quite deeply by Russian forensic specialists. Meanwhile, expert practice sets forth tasks that are associated with the emergence of new firearm samples and new methods of laboratory and instrumental diagnosis.

Experimental and numerical study on failure mechanisms of bone simulants subjected to projectile impact.

Analyses of the human bones failure mechanisms under projectile impact conditions can be made through performing of a large number of ballistic trials. But the amount of data that can be collected during ballistic experiments is limited due to the high dynamics of the process and its destructive character. Numerical analyses may support experimental methodologies allowing to better understand the principles of the phenomenon. Therefore, the main aim of the study was to create and to verify a numerical model of commercially available synthetic bone material-Synbone®. The model could be used in the future as a supporting tool facilitating forensic studies or designing processes of personal protection systems (helmets, bulletproof vests, etc.). Although Synbone® is commonly used in the ballistic experiments, the literature lacks reliable numerical models of this material. In order to define a numerical model of Synbone®, mechanical experiments characterizing the response of the material to the applied loads in a wide range of strains and strain rates were carried out. Based on the mechanical tests results, an appropriate material model was selected for the Synbone® composite and the values of constants in its equations were determined. Material characterization experiments were subsequently reproduced with numerical simulations and a high correlation of the results was obtained. The final validation of the material model was based on the comparison of the ballistic impact experiments and simulation results. High similarity obtained (relative error lower than 10%) demonstrates that the numerical model of Synbone® material was properly defined.

[Characteristics of the trajectory of projectiles after penetration of biological and non-biological obstacles in shots fired from various types of firearms]. / Kharakteristika traektorii dvizheniya snaryadov posle probitiya biologicheskikh i nebiologicheskikh pregrad pri vystrelakh iz razlichnykh obraztsov ognestrel'nogo oruzhiya.

The purpose of the work was to study the movement trajectory of the projectile after breaking through an obstacle made of various materials installed at various angles to the aiming line when firing from rifled and traumatic weapons. As a result of a series of experimental shots by shells fired from a traumatic pistol «Jorge¼ (9×22 mm RA cartridge with an initial velocity of 300±20 m/s and a bullet weight of 0.7 g) and the Blaser R93 carbine (Norma Jaktmatch 9.3×62 mm hunting cartridge with an initial speed of 765 m/s and a bullet weight of 11 g) it has been found that, when punching both biological simulators and triplex glass located at the angles of 40-60° with respect to the aiming line, a deflection of the firearm from the aiming line is observed.

[Morphological characteristics of gunshot injuries resulting from ricochet depending on type of experimental barrier]. / Morfologicheskaya kharakteristika ognestrel'nykh povrezhdenii, obrazovavshikhsya v rezul'tate rikosheta, v zavisimosti ot vida eksperimental'noi pregrady.

The purpose of this study was to establish a set of distinctive features of the qualitative and quantitative parameters of gunshot injuries resulting from the ricochet of a bullet and buckshot when firing from a smooth-bore weapon, depending on the type of experimental barrier. As a result of the ballistic experiment, a list of statistically significant characteristics of input gunshot injuries of biological and non-biological targets formed when firing with a bullet and buckshot followed by a ricochet was revealed, which will enable to determine the sought type of barrier from the two suggested options: «Concrete 2¼ or «Brick¼, «Concrete 2¼ or «Metal¼, «Brick¼ or «Metal¼. Besides, a list of characteristics of input gunshot injuries has been established, the parameters of which are under statistically significant influence of the type of experimental barrier. The revealed patterns can be used to reconstruct the circumstances of an incident during situational examination depending on the characteristics of input gunshot injuries as a result of a ricochet when firing from a smooth-bore weapon.

[Effect of the target type on the characteristics of gunshot injuries resulting from bullet and shrapnel ricochet]. / Vliyanie vida misheni na kharakteristiku ognestrel'nykh povrezhdenii, obrazuyushchikhsya v rezul'tate rikosheta puli i kartechi.

The study objective is to establish the effect of the type of experimental target (biological, non-biological) on the forensic medical characteristics of gunshot injuries resulting from bullet and shrapnel ricochet when fired from a smooth-bore weapon. Differences in the skin and clothing or their imitators render different morphological patterns of the input gunshot injuries. Based on the results of the ballistic experiment, a list of statistically significant differences in the qualitative and quantitative characteristics of the input gunshot injuries to biological and non-biological targets as a result of a ricochet when a bullet is fired from a smooth-bore weapon was compiled. In addition, the characteristics of the input gunshot injuries were established, demonstrating statistically significant differences only in certain combinations of the specified types of bullet and experimental target. The results obtained can be used in medical forensic examinations of gunshot injuries.

Wound ballistics and the unusual injuries of the tandem bullet phenomenon: A systematic review of case-specific characteristics.

This study revisited the forensic literature to compile case-specific characteristics of the tandem-bullet phenomenon (TBP). A systematic review was performed following the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) and The Joanna Briggs Institute's manual. The protocol was registered in Open Science Framework. Ten primary databases and two sources of grey literature were searched, with descriptive studies on TBP, with information about the victim, weapon, ammunition and injuries, being included. From an initial sample of 2360 studies, 13 were eligible. The studies reported 11 male and 2 female victims, with ages between 14 and 63 years (mean = 39.45 ± 14.51 years); seven were victims of suicide (or suicide attempt); most of the victims (69.23%) were shot in the head and neck; and most (84.61%) had an entry and exit wound ratio of 1:0, respectively. The use of image exams to assess injuries and bullets was reported in 12 cases (92.30%). The most frequent reasons for the TBP were the mismatch between weapon and ammunition and the use of defective cartridges (76.92%). Forensic professionals must be aware of the case-specific characteristics of the TBP to overcome confounding factors in wound ballistics and medicolegal examinations.

Differing sizes of bullet entrance holes in skin of the anterior and posterior trunk.

The aim of the present study was to establish whether the size (diameter and area) of bullet entrance holes in skin varies between distant shots to the anterior and posterior trunk, respectively, when using the same ammunition (in concreto pistol cartridges 9 mm Luger). For that purpose, specimens of porcine skin from the belly region and the back were taken (10 samples each) and shot at from a distance of 1.6 m. The entrance holes were photo-documented under standardised conditions. After image processing for contrast enhancement, the maximum diameter and the area of each skin defect were measured automatically by means of an image analysis system. Both size parameters differed significantly depending on the body region affected. On the back with its comparatively thick dermis, the skin defects were considerably smaller than those on the ventral trunk where the corium is less thick. This difference can be explained by the fact that the elastic properties of skin are strongly determined by the connective tissue which is especially rich in fibres. The study results were consistent with the authors' casework experience and support the assumption that the entrance site of gunshot wounds has a major influence on the size of the bullet hole in skin.

A combined cowhide/gelatine soft tissue simulant for ballistic studies.

The ballistic resistance of a combined soft tissue simulant was studied, consisting of gelatine as a simulant for human muscle tissue and tanned cowhide (leather) as a simulant for human skin. The simulant was manufactured by applying cowhide to liquid ballistic gelatine, as the gelatine solidified in its mould. Combining a skin and muscle tissue simulant in this adhered way opens the possibility to produce purpose-built proxies for human body parts in ballistic studies or for forensic shooting incident reconstructions. Ballistic resistance of adhered cowhide - (bonded) to solidifying ballistic gelatine - was compared to that of the same material applied on gelatine blocks in loose condition. Ballistic resistance of tanned cowhide was found to be more consistent in adhered condition. This enhanced consistency is a benefit, increasing reproducibility of results in ballistic studies. Additionally, two ways to assess ballistic resistance of a skin simulant were described and compared. Logistic regression, from a number of measured velocities and associated (non)perforations is recommended for testing ballistic resistance.