Bullet Fragmentation Research Articles

Body models in forensic ballistics: reconstruction of a gunshot injury to the chest by bullet fragmentation after shooting through a finger

Forensic science uses substitutes to reconstruct injury patterns in order to answer questions regarding the dynamic formation of unusual injuries. Using a case study, an experimental simulation of a finger was designed, for the first time with a combination of hard wood and glycerin soap. With this model as an intermediate target simulation, it was possible not only to demonstrate the “bullet-body (finger) interaction”, but also to recreate the wound pattern found in the victim. This case demonstrates that by using ballistic models and body-part substitutes, gunshot cases can be reproduced simply and economically, without coming into conflict with ethical guidelines.

The effects of retained lead bullets on body lead burden.

Numerous case reports have demonstrated that lead poisoning with potentially fatal consequences can result from retained lead projectiles after firearm injuries. To assess the impact of retained projectiles on subsequent lead exposure in the population, one cannot rely on self-selected cases presenting with symptoms of lead intoxication. This preliminary study seeks to identify increased lead burden and identify risk factors of elevated blood lead levels for individuals with retained lead bullets. Forty-eight patients were originally recruited from gunshot victims presenting for care at the King/Drew Medical Center in Los Angeles, California. An initial blood level was measured for all recruited patients and repeated for the 28 participants available for follow-up, 1 week to 8 months later. Medical history, including a history of prior firearm injuries and other retained projectiles, was taken, along with a screening and risk factor questionnaire to determine other sources of lead (occupational/recreational) to which the patient might have been, or is at present, exposed. The participants also had K-shell x-ray fluorescence determinations of bone lead in the tibia and calcaneus in order to determine past lead exposures not revealed by medical history and risk factor questionnaire. Multivariate models of blood level were made using risk factor and bone lead concentration data. We demonstrated that blood lead tends to increase with time after injury in patients with projectile retention, and that the increase in significant part depended on the presence of a bone fracture caused by the gunshot. We encountered evidence suggesting that the amount of blood lead increase in time after injury is also dependent on the tibia lead concentration. There were too few cases in the study to fully test the effects of bullet location, or the interaction of bullet location with bone fracture or bullet fragmentation.

The MEN frangible: study of a new bullet in gelatin. Metallwerk Elisenhütte Nassau.

Experimental gunshots were made with 9 x 19 mm (9-mm Luger) Frangible ammunition using skin, gelatin, and bones as targets. Direct gunshots penetrated 50 cm into gelatin blocks without mushrooming or fragmentation. Skull bone was easily perforated. Head models were penetrated by the bullets, which broke down to myriad fragments within or outside the head. Gunshots through windshields and steel plates led to dangerous bullet fragmentation with a high risk of injury. Gunshots perforating tibias produced comminuted fractures. In all soft tissues, except the direct gunshots into gelatin, high-resolution radiography revealed many metallic fragments along the bullet path. Clinical radiography can show the larger copper fragments, but the explosion-like distribution of metallic foreign bodies in soft tissue is a serious surgical problem.

The Magnetohydrodynamics of Supersonic Gas Clouds: MHD Cosmic Bullets and Wind‐swept Clumps

We report an extensive set of two-dimensional MHD simulations exploring the role and evolution of magnetic fields in the dynamics of supersonic plasma clumps. We examine the influence of both ambient field strength and orientation on the problem. Of those two characteristics, field orientation is far more important in the cases we have considered with β0 = pg/pb ≥ 1. That is due to the geometry-sensitivity of field stretching/amplification from large-scale shearing motions around the bullet. When the ambient magnetic field is transverse to the bullet motion, even a very modest field, well below equipartition strength, can be amplified by field line stretching around the bullet within a couple of bullet crushing times so that Maxwell stresses become comparable to the ram pressure associated with the bullet motion. The possibility is discussed that those situations might lead to large, induced electric potentials capable of accelerating charged particles. When the ambient field is aligned to the bullet motion, on the other hand, reconnection-prone topologies develop that shorten the stretched field and release much of the excess energy it contains. In this geometry, the Maxwell stresses on the bullet never approach the ram pressure level. In both cases, however, the presence of a field with even moderate initial strength acts to help the flow realign itself around the bullet into a smoother, more laminar form. That reduces bullet fragmentation tendencies caused by destructive instabilities. Eddies seem less effective at field amplification than flows around the bullet, because fields within eddies tend to be expelled to the eddy perimeters. Similar effects cause the magnetic field within the bullet itself to be reduced below its initial value over time.For oblique fields, we expect that the transverse field cases modeled here are more generally relevant. What counts is whether field lines threading the face of the bullet are swept around it in a fashion that folds them (leading to reconnection) or that keeps them unidirectional one each side of the bullet. In the second instance, behaviors should resemble those of the transverse field cases. We estimate that this quasi-transverse behavior is appropriate whenever the angle, θ, between the motion and the field satisfies tan θ 1/M, where M is the bullet Mach number.From these simulations, we find support in either field geometry for the conclusions reached in previous studies that nonthermal radio emission associated with supersonic clumps is likely to be controlled largely by the generation of strong magnetic fields around the perimeters of the clumps, rather than local particle acceleration and field compression within the bow shock. In addition, since the magnetic pressure on the nose of the bullet likely becomes comparable to the ram pressure and hence the total pressure behind the bow shock, the gas pressure there could be substantially lower than that in a gasdynamical bullet. That means, as well, that the temperature in the region on the nose of the bullet would be lower than that predicted in the gasdynamical case. That detail could alter expectations of the thermal emission, including X-rays and UV-IR lines.

Wounding Characteristics of .38 Caliber Revolver Cartridges

Abstract Injury patterns in both artificial media and animal tissues were analyzed, and the results were then correlated with autopsy findings in subjects who died from gunshot wounds to determine the wounding characteristics of bullets from two standard .38 caliber revolver cartridges. The 150-grain round nose bullet, in comparison with a 110-grain semi-jacketed controlled-expansion round (hollowpoint bullet), was found to have greater penetration and a greater tendency to deviate from its flight path. The controlled expansion round was found to produce a wider bullet track with greater deformation and bullet fragmentation than the round nose ammunition in artificial media and animal tissue. Autopsy study of shooting victims indicated more through-and-through wounds with round nose bullets than with hollowpoint rounds, and overall survival in shooting victims was greater with roundnose bullets, but was modified by site of injury and availability of prompt medical treatment. Neither round appeared to differ in inherent “knockdown” power. Though distinct differences in wounding patterns can be demonstrated in artificial and animal media, the differences between round nose and controlled expansion round bullets are not marked in actual human subjects with gunshot wounds.

Determination of Shooting Distance from Deformation of the Recovered Bullet

Abstract A method is reported for estimating shooting distance by comparing the amount of bullet deformation of a recovered bullet with that produced in a series of test bullets fired into 10% ordnance gelatin at 4°C. Bullet deformation and fragmentation pattern in this gelatin was previously found to be comparable to that seen in living animal muscle. Striking velocities of the test bullets were lowered stepwise until a test bullet was produced with less deformity than the evidence bullet. Two shots were then made through the abdomen of a fresh swine cadaver at velocities approximating those of the last two test shots in gelatin. This served as verification of the gelatin's calibration against animal tissue and gave an additional set of bullets whose degrees of deformation bracketed that of the evidence bullet. Separate interpolations were done for bullet length, average bullet tip diameter, and bullet weight using both sets of bracketing test bullets. The resulting velocities were then converted to distances using the manufacturer's velocity tables. The average of the interpolations was 256 yds (234 m); all six fell within a range of 33 yds (30 m) (from 238 to 271 yds [218 to 248 m]).