Review of wound ballistic research and its applicability to wildlife management

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.

Weight retention and expansion of popular lead-based and lead-free hunting bullets

Hunting bullets are often comprised of a lead core covered with a copper alloy jacket. When the bullet collides with an animal, particles-sometimes millions-can shed from the projectile and embed in animal tissues. Those lead fragments can persist in game meat and remain in the discarded viscera that many wildlife species scavenge. Bullets often differ in design, so it is vital to assess their weight retention and expansion, which affects how much metal they deposit in tissue and how effectively they kill animals. We fired 12 types of hunting bullets into water to measure their weight retention and expansion at 91 m and 238 m (100 and 260 yards). Bullet constructions included copper, tin, bonded lead, partitioned lead, and cup-and-core lead. On average, copper bullets retained >98 % of their weight, whereas cup-and-core lead bullets retained <13-55 %, depending on the brand and shot distance. One brand of bonded lead bullet retained mass (≥96 %) nearly as well as copper bullets, while another brand retained much less (~71 %). Two types of copper bullets expanded similarly between test distances, while a third expanded less at 238 m. Cup-and-core lead bullets often experienced a separation between their copper alloy jacket and lead core. Our data emphasize that lead-based bullets of similar construction can drastically differ in weight retention and expansion.

Study on chest injury and bulletproof vest protection under the combined action of blast wave and fragments

Using a simulation based method, this paper analysis the damage effect of blast wave and fragments on human body and the protective effect of bulletproof vest. The results show that compared with the single blast shock wave, the chest injury is more serious under the combined action of blast shock wave and fragments. The peak stress of sternum, costal cartilage and rib increases by 334.34%, 170.23% and 39.72%, respectively. The peak stress on the side of the lung decreases by 3.95%, with little change. The peak stress on the front and back of the lung increases by 83.58% and 409.09% respectively. Overall, the lung injury is aggravated. With the addition of the bulletproof vest, the damage caused by fragments is reduced, and the peak stress of the sternum and the costal cartilage decreases by 48.77% and 69.78%, respectively. Due to the interaction of the blast wave with the vest and the chest, the damage caused by blast wave is aggravated. The peak stress of rib increases by 13.55%, and the peak stress of lung front, side and back increases by 1.22%, 6.51% and 3.57%, respectively.

Animal welfare testing for shooting and darting free-ranging wildlife: a review and recommendations

Several important techniques for managing wildlife rely on ballistics (the behaviour of projectiles), including killing techniques (shooting) as well as capture and marking methods (darting). Because all ballistic techniques have the capacity to harm animals, animal welfare is an important consideration. Standardised testing approaches that have allowed refinement for other physical killing and capture methods (e.g. traps for mammals) have not been applied broadly to ballistic methods. At the same time, new technology is becoming available for shooting (e.g. subsonic and lead-free ammunition) and darting (e.g. dye-marker darts). We present several case studies demonstrating (a) how basic ballistic testing can be performed for novel firearms and/or projectiles, (b) the benefits of identifying methods producing undesirable results before operational use, and (c) the welfare risks associated with bypassing testing of a technique before broad-scale application. Following the approach that has been used internationally to test kill-traps, we suggest the following four-step testing process: (1) range and field testing to confirm accuracy and precision, the delivery of appropriate kinetic energy levels and projectile behaviour, (2) post-mortem assessment of ballistic injury in cadavers, (3) small-scale live animal pilot studies with predetermined threshold pass/fail levels, and (4) broad-scale use with reporting of the frequency of adverse animal welfare outcomes. We present this as a practical approach for maintaining and improving animal welfare standards when considering the use of ballistic technology for wildlife management.

Oxpeckers Help Rhinos Evade Humans

Evolutionary theory expects social, communicative species to eavesdrop most on other species' alarm calls [e.g., 1, 2] but also that solitary-living species benefit most from eavesdropping [3, 4]. Examples of solitary species responding to the alarm calls of other species, however, are limited and unconvincing [3-5]. The Swahili name for the red-billed oxpecker (Buphagus erythrorynchus) is Askari wa kifaru, the rhinos' guard [6]. Black rhino (Diceros bicornis) are a solitary-living, non-vocal species and are critically endangered through hunting. We searched Hluhluwe-iMfolozi Park, South Africa, for rhinoceros for 27 months with and without the aid of radio telemetry and conducted 86 experimental, unconcealed approaches to 11 rhino, without or with varying numbers of resident oxpecker. Oxpeckers enabled rhinos to evade detection by us in 40% to 50% of encounters. Alarm-calling by oxpeckers significantly improved the rate and distance that rhinos detected our approach from 23% to 100% and 27 ± 6 m to 61 ± 4 m, respectively. Every additional oxpecker improved detection distance by 9 m. Rhinos alerted by oxpeckers' alarm calls never re-oriented in our direction but moved to face downwind. Thus, oxpeckers' calls communicate only threat proximity, not direction, and rhinos assume the hunter is stalking from downwind. We confirm that oxpeckers guard rhinos and the importance of depredation, not sociality, in the evolution of eavesdropping [4, 7]. Conservationists should consider reintroducing oxpeckers to rhino populations, reinstating their anti-human sentinel [8]. VIDEO ABSTRACT.

Unleaded hunting: Are copper bullets and lead-based bullets equally effective for killing big game?

Semi-jacketed lead-cored or copper-based homogenous rifle bullets are commonly used for hunting big game. Ever since their introduction in the 1990's, copper-based bullets have not been widely accepted by hunters due to limited supply, higher expense, and the perception that they exhibit inferior killing efficiency and correspondingly higher wounding rates. Here, we present data showing that animal flight distances for roe deer, red deer, brown bear, and moose dispatched with lead- or copper-based hunting bullets did not significantly differ from an animal welfare standardized animal flight distance based on body mass. Lead-cored bullets typical fragment on impact, whereas copper-based bullets retain more mass and expand more than their leaden counterparts. Our data demonstrate that the relative killing efficiency of lead and copper bullets is similar in terms of animal flight distance after fatal shots. Hunters that traditionally use lead bullets should consider switching to copper bullets to enhance human and environmental health.

Assessment of humaneness using gunshot targeting the brain and cervical spine for cervid depopulation under field conditions

Population reduction or eradication of domestic or non-domestic species may be required to address their impacts on the environment, other species, or human interests. Firearms are often used to accomplish these practical management objectives, and there is increased concern that the methods used may compromise animal welfare. We document the accuracy and humaneness of gunshot placement to the brain and cervical vertebrae of Philippine deer (Rusa marianna) on Guam during depopulation activities as a model for meeting AVMA standards of euthanasia under field conditions (e.g., animal is not in hand). Deer were shot with a .223 caliber rifle from 10-125 m and approached immediately (<20 s) for assessment. A subset of adult deer was further evaluated for physiological responses including cessation of heart rate, respiration, ocular reflexes, and post-mortem spasms. All deer shot in the brain (n = 132) and upper cervical spine (C1-C3; n = 18) died immediately due to the destruction of the brain or spinal tissue. Shot placements were all within 1.9 cm of the point of aim (i.e., the center of the target region). The accuracy and immediate insensibility resulting from targeting of C1-C3 demonstrates that this is an alternative target site when animal positioning is not optimal for targeting the brain, or there is a need to preserve brain tissue (e.g., Chronic Wasting Disease testing). While targeting of C4 -C7 vertebrae (n = 6) was accurate and resulted in immediate incapacitation, the failure to produce immediate insensibility does not support the use of this shot placement when upper cervical or brain shot placement is an option. It is reasonable to achieve sufficient accuracy to target the brain or upper cervical vertebrae of deer under field conditions and meet standards of euthanasia while accomplishing management objectives.

Defining animal welfare standards in hunting: body mass determines thresholds for incapacitation time and flight distance

Shooting is an important tool for managing terrestrial wildlife populations worldwide. To date, however, there has been few quantitative methods available enabling assessment of the animal welfare outcomes of rifle hunting. We apply a variety of factors to model flight distance (distance travelled by an animal after bullet impact) and incapacitation from the moment of bullet impact. These factors include body mass, allometric and isometric scaling, comparative physiology, wound ballistics and linear kinematics. This approach provides for the first time a method for quantifying and grading the quality of shooting processes by examining only body mass and flight distance. Our model is a universally applicable tool for measuring animal welfare outcomes of shooting regimes both within and among species. For management agencies the model should be a practical tool for monitoring and evaluating animal welfare outcomes regarding shooting of mammalian populations.

Heads in the sand: public health and ecological risks of lead-based bullets for wildlife shooting in Australia

Lead (Pb) is a toxic element banned from fuel, paint and many other products in most developed countries. Nonetheless, it is still widely used in ammunition, including rifle bullets, and Pb-based bullets are almost universally used in Australia. For decades, poisoning from Pb shot (shotguns) has been recognised as a cause of disease in waterfowl and Pb shot has been subsequently banned for waterfowl hunting in many jurisdictions. However, the risks posed by Pb-based bullets (rifles) have not been similarly recognised in Australia. Pb-based rifle bullets frequently fragment, contaminating the tissue of shot animals. Consuming this Pb-contaminated tissue risks harmful Pb exposure and, thus, the health of wildlife scavengers (carrion eaters) and humans and their companion animals who consume harvested meat (game eaters). In Europe, North America and elsewhere, the environmental and human health risks of Pb-based bullets are widely recognised, and non-toxic alternatives (e.g. copper-based bullets) are increasingly being used. However, Australia has no comparable research despite widespread use of shooting, common scavenging by potentially susceptible wildlife species, and people regularly consuming shot meat. We conclude that Australia has its collective ‘head in the sand’ on this pressing worldwide One Health issue. We present the need for urgent research into this field in Australia.

Ground Squirrel Shooting and Potential Lead Exposure in Breeding Avian Scavengers

Recreational ground squirrel shooting is a popular activity throughout the western United States and serves as a tool for managing ground squirrel populations in agricultural regions. Belding's ground squirrels (Spermophilus beldingi) are routinely shot in California, Nevada, and Oregon across habitats that overlap with breeding avian scavengers. Ground squirrels shot with lead (Pb)-based bullets may pose a risk to avian scavengers if they consume carcasses containing Pb fragments. To assess the potential risk to breeding avian scavengers we developed a model to estimate the number, mass, and distribution of Pb fragments in shot ground squirrels using radiographic images. Eighty percent of shot carcasses contained detectible Pb fragments with an average of 38.6 mg of Pb fragments. Seven percent of all carcasses contained Pb fragment masses exceeding a lethal dose for a model raptor nestling (e.g. American kestrel Falco sparverius). Bullet type did not influence the number of fragments in shot ground squirrels, but did influence the mass of fragments retained. Belding's ground squirrels shot with .17 Super Mag and unknown ammunition types contained over 28 and 17 times more mass of Pb fragments than those shot with .22 solid and .22 hollow point bullets, respectively. Ground squirrel body mass was positively correlated with both the number and mass of Pb fragments in carcasses, increasing on average by 76% and 56% respectively across the range of carcass masses. Although the mass of Pb retained in ground squirrel carcasses was small relative to the original bullet mass, avian scavenger nestlings that frequently consume shot ground squirrels may be at risk for Pb-induced effects (e.g., physiology, growth, or survival). Using modeling efforts we found that if nestling golden eagles (Aquila chrysaetos), red-tailed hawks (Buteo jamaicensis), and Swainson's hawks (B. swainsoni) consumed shot ground squirrels proportionately to the nestling's mass, energy needs, and diet, 100% of the nestling period would exceed a 50% reduction in delta-aminolevulinic acid dehydratase production threshold, the last 13-27% of the nestling stage would exceed a reduced growth rate threshold, but no nestlings would be expected to exceed a level of Pb ingestion that would be lethal.

Estimating Lead Fragmentation from Ammunition for Muzzleloading and Black Powder Cartridge Rifles

Lead bullet fragments pose a health risk to scavengers and hunters consuming game meat, but lead or lead-core bullets are still commonly employed for big and small game hunting. Bullet fragmentation has been assessed for modern, high-velocity rifles, but has not been well documented for black-powder cartridge rifles or muzzleloading firearms. We used two established methods to estimate bullet fragmentation. We evaluated a traditional .54 round ball and a modern-designed .54 conical bullet for muzzleloaders, two types of .45-70 black powder rifle cartridges, and a modern lead-core high-velocity bullet (.30-06) as our comparison control. We tested penetration and fragmentation in water (n = 12) and ballistics gel (n = 2) for each bullet type. We measured lead mass lost to fragmentation and x-rayed ballistic gels to visualize fragmentation patterns. The modern .30-06 bullets we tested (Remington Core-Lokt) retained a mean of only 57.5% of original mass, whereas mean retention by muzzleloader and black powder cartridge bullets ranged 87.8-99.7%. Round balls and .45-70 bullets shed less lead (i.e., 0.04g and 0.19g on average respectively) than the modern conical .54 muzzleloading bullets (3.08g) or the .30-06 control (4.14g). Fragments from round balls and black powder cartridge bullets showed far less lateral spread compared to the high-velocity modern bullet. Our findings suggest that round balls for muzzleloaders and black powder cartridge bullets may leave far fewer lead fragments in game than the conical muzzleloader bullet or modern high-velocity rifle bullet we tested, and thus could pose a lower risk of secondary lead poisoning for humans and wildlife. Artificial tests cannot replicate conditions encountered in the field, but the striking differences we observed in bullet fragmentation even under severe testing conditions suggests that follow-up tests on game animals may be warranted.

Performance of lead-free versus lead-based hunting ammunition in ballistic soap

Background

Lead-free hunting bullets are an alternative to lead-containing bullets which cause health risks for humans and endangered scavenging raptors through lead ingestion. However, doubts concerning the effectiveness of lead-free hunting bullets hinder the wide-spread acceptance in the hunting and wildlife management community.

Methods

We performed terminal ballistic experiments under standardized conditions with ballistic soap as surrogate for game animal tissue to characterize dimensionally stable, partially fragmenting, and deforming lead-free bullets and one commonly used lead-containing bullet. The permanent cavities created in soap blocks are used as a measure for the potential wound damage. The soap blocks were imaged using computed tomography to assess the volume and shape of the cavity and the number of fragments. Shots were performed at different impact speeds, covering a realistic shooting range. Using 3D image segmentation, cavity volume, metal fragment count, deflection angle, and depth of maximum damage were determined. Shots were repeated to investigate the reproducibility of ballistic soap experiments.

Results

All bullets showed an increasing cavity volume with increasing deposited energy. The dimensionally stable and fragmenting lead-free bullets achieved a constant conversion ratio while the deforming copper and lead-containing bullets showed a ratio, which increases linearly with the total deposited energy. The lead-containing bullet created hundreds of fragments and significantly more fragments than the lead-free bullets. The deflection angle was significantly higher for the dimensionally stable bullet due to its tumbling behavior and was similarly low for the other bullets. The deforming bullets achieved higher reproducibility than the fragmenting and dimensionally stable bullets.

Conclusion

The deforming lead-free bullet closely resembled the deforming lead-containing bullet in terms of energy conversion, deflection angle, cavity shape, and reproducibility, showing that similar terminal ballistic behavior can be achieved. Furthermore, the volumetric image processing allowed superior analysis compared to methods that involve cutting of the soap blocks.

Quantitative analysis of animal-welfare outcomes in helicopter shooting: a case study with feral dromedary camels (Camelus dromedarius)

Context Helicopter shooting is a common and effective tool for reducing overabundant wildlife populations. However, there is little quantitative information on the humaneness of the method, leading to uncertainty in wildlife-management policy. There is, subsequently, a need for an improved understanding of the welfare implications of helicopter shooting. Aim A study was undertaken to infer the humaneness of helicopter shooting for a case study species, the feral dromedary camel (Camelus dromedarius). Methods Seven post-mortem studies (n = 715) and one ante-mortem study (n = 192) were undertaken during routine helicopter shooting programs of free-ranging camels. In these studies, we measured four animal-welfare parameters to allow inference on the humaneness of the technique. These parameters were time to death, instantaneous death rate (proportion of animals for which time to death = 0), wounding rate and location of bullet-wound tract. We also modelled these welfare variables against hypothesised explanatory variables to assist improvement of future programs. Key results The mean wounding rate was 0.4%, and the killing efficacy of the technique was 99.6%. Mean time to death was 4 s, and mean instantaneous death rate was 83%. Each animal displayed a mean 2.4 bullet-wound tracts, with 75%, 63% and 35% of animals shot at least once in the thorax, cranium and cervical spine, respectively. Regression analysis revealed that the identity of the shooter and the nature of the local vegetation were the most important factors associated with an animal experiencing an inferred instantaneous death or not. Conclusions Helicopter shooting of feral camels produces a very low wounding rate and rapid time to death. Shooter identity is the most important consideration for determining animal-welfare outcomes. Improvements to the humaneness of programs can be made by increasing the rigour of shooter selection and training. Implications Wildlife killing methods must be demonstrated to be humane to receive public support; however, few shooting methods are objectively examined. Helicopter shooting can be independently examined and operators assessed. Adoption of this examination template may allow continual improvement by industry as well as increasing societal acceptance of helicopter shooting.