Pig Organ Energy Loss Comparison Experiments Using BBs.

Torso models for ballistics research require that the mechanical properties of simulant materials must match the heterogeneous nature of tissues/organs within the human thorax/abdomen. A series of energy loss experiments were conducted on fresh porcine organs/tissues at room temperature and 37°C, using steel 4.5 mm BBs fired from a Daisy(®) brand air rifle. They were compared to FBI and NATO specification ordnance gelatin and a candidate surrogate material called Simulant "A". Two CED M2 chronographs measured BB velocity. The resulting energy loss was established using KE = 1/2 mv² before and after target perforation. The combined results at room temperature and 37°C were as follows: FBI specification gelatin was similar (p > 0.05) to heart and lung, spleen was similar to NATO specification gelatin, Simulant "A" was similar to hindquarter muscle, and hindquarter muscle, kidney, and spleen were similar to each other regarding energy retardation. These results can be used as a basis for the development of simulant materials to create an anatomically correct heterogeneous model.

An Analysis of the Characteristics of Thoracic and Abdominal Injuries Due to Gunshot Homicides in Israel.

De-identified wound data from 197 homicidal gunshot postmortems were obtained between 2000 and 2008. Forensic ballistics data were only available for cases between 2004 and 2008. Males represent 91% of gunshot victims and were struck in the thorax/abdomen with an average of 2.3 bullets. The type of firearms involved were semi-automatic pistols in the predominant caliber 9-mm Luger and assault rifles in caliber 5.56 × 45 mm and caliber 7.62 × 39 mm Soviet, using full metal jacket bullets. The majority of shootings occurred at ranges of 1 m or greater. The most common bullet path was front to back in 66% of cases. Entry wounds occurred more often on the left side of the thorax, abdomen, and back. The most common critical organs/tissues to sustain bullet trauma in descending order were as follows: heart, lungs, liver, aorta, spleen, kidneys, and vena cava. Ribs were struck by most bullets that entered the thorax.

Ballistics ordnance gelatine - How different concentrations, temperatures and curing times affect calibration results.

A study was undertaken to determine whether different concentrations of ordnance gelatine, water types, temperatures and curing times would have an effect on projectile penetration of a gelatine tissue surrogate. Both Federal Bureau of Investigation (FBI) and North Atlantic Treaty Organization (NATO) specified gelatines were compared against the FBI calibration standard. 10% w/w and 20% w/w concentrations of gelatine with Bloom numbers of 250 and 285 were prepared and cured at variable temperatures (3-20°C) for 21 hours-3 weeks. Each block was shot on four occasions on the same range using steel calibre 4.5 mm BBs fired from a Daisy(®) air rifle at the required standard velocity of 180 ± 4.5 m/s, to ascertain the mean penetration depth. The results showed no significant difference in mean penetration depth using the three different water types (p > 0.05). Temperature changes and curing times did affect penetration depth. At 10°C, mean penetration depth with 20% gelatine 285 Bloom for the two water types tested was 49.7 ± 1.5 mm after 21 h curing time, whereas the same formulation at 20°C using two different water types was 79.1 ± 2.1 mm after 100 h curing time (p < 0.001). Neither of the NATO 20% concentrations of gelatine at 10°C or a 20% concentration of 285 Bloom gelatine at 10°C met the same calibration standard as the FBI recommended 10% formulation at 4°C. A 20% concentration of 285 Bloom at 20°C met the same calibration/penetration criteria as a 10% concentration of 250 Bloom at 4 °C after 100 h of curing, therefore matching the FBI calibration standard for a soft tissue simulant for wound ballistics research. These results demonstrate significant variability in simulant properties. Failure to standardise ballistic simulants may invalidate experimental results.