Time since discharge of shotgun shells

A technique for the estimation of time since discharge of a given class of spent shotgun shells is presented. The technique involved the use of SPME (Solid Phase Microextraction) sampling from the atmosphere inside spent shotgun shells. Compounds absorbed on the SPME fiber were desorbed and analyzed with GC-MS. The decrease in concentration of the combustion product naphthalene was monitored in all shells over a two-month period. Three conditions were examined to prevent naphthalene from escaping prior to testing the shells. A glass vial was successfully incorporated to halt the dissipation of naphthalene. At room temperature the naphthalene peak can be measured for several months and the curve-fitting data can lead to an estimation of time since discharge.     

An unusual shotgun injury pattern produced by an intermediate target

Discharge of a shotgun with a shotgun casing in its muzzle as a "dust cover" produced a pattern of injuries suggestive of combined intermediate- and distant-range wounds.     

Unusual blunt force wound produced by a gun muzzle

Most blunt force injuries produced by guns are associated with gun butts, and patterned, muzzle/sight impressions are usually produced by discharging firearms. An unusual and distinct forehead laceration produced by a blow with the muzzle end of a .32 caliber revolver is presented.     

A distant-range, suicidal shotgun wound of the back

The case being reported is one of a shotgun fatality with a thoracic back wound. A 23-year-old man was shot from a distance with trajectories going from back to front and on a nearly horizontal level. These findings observed in the autopsy could represent homicide, but scene investigation and police records were interpreted and it became clear that the case was suicide. Thus, this case shows that the determination of the manner of death requires a careful forensic investigation including autopsy findings, scene investigation, and reconstruction of the events.     

A new type of shotgun ammunition produces unique wound characteristics

The Tucson Police Department, Tucson, AZ, has begun using the Polyshok Impact Reactive Projectile (IRP), a new type of shotgun ammunition that includes a lead bead core that travels within single, plastic-encased projectile. On impact, the core is released to distribute over a small area, thereby disintegrating on impact to reduce the likelihood of exit or collateral damage on missed shots. After a brief review of shotgun slug ballistics and wound characteristics and a discussion of the mechanism of the Polyshok IRP, we report the first death in the United States from this ammunition. Findings included a single entrance wound with plastic ammunition components and small lead particles recovered from the body, the combination of which normally would suggest a close-range shooting with birdshot. However, the characteristics of this ammunition create different patterns than are found with slugs or shot, so that a medical examiner unfamiliar with the Polyshok IRP could draw inaccurate conclusions about ammunition and range of fire. Because the single projectile fired from this ammunition is composed of both plastic and lead, plastic components are likely to be found within the wound at any range of fire, unlike traditional shot or slug ammunition. Also, the small size of lead particles found spread through the wound cavity would ordinarily suggest a small-size shot, whereas the external appearance of the wound (a single entrance with no dispersion of shot) and the pattern of tissue destruction are more consistent with the patterns of injury associated with shotgun slugs.     

An evaluation of distribution of pellets due to shotgun discharge

Dispersion of pellets due to shotgun discharge has been considered in terms of a Gaussian distribution. Only approximate results are obtained in forensic ballistic cases, but when these are compared with the empirical findings of Burrard, they are found to be reasonably satisfactory. Limitations of the model are discussed.     

Maximum range of pellets fired from a shotgun

A mathematical model to determine the maximum range of pellets fired from a shotgun has been suggested. It has been assumed that the air resistance experienced by a pellet is proportional to the square of its velocity (?μV²) where $\text{μ =}\text{A}\text{C}$ with

$\text{C=0.061}\text{86}\text{N}{}^{\mathrm{<mtext>1</mtext><mtext>3</mtext>}}$

and

$\text{A=}\text{1}\text{[17 696+2N+10 000(0.2?d)]}$

N is the number of pellets/ounce and d is the diameter of the pellets in inches. A method for calculating the maximum range has been suggested, and the values obtained for Buck 00, size 8 and size 9 American pellets are very close to the reported experimental observations. The maximum ranges for other sizes of pellets have also been calculated. The angle of projection decreases with increase in velocity and increases with increase in the weight of the pellet. It varies between 26° to 32° for common sizes of pellets and standard shotgun velocity. The maximum range in air is only 1 – 3% of the range attained by a pellet in vacuum.     

差示扫描量热法检验猎枪弹丸

目的对不同厂家的猎枪弹丸进行区分和鉴别。方法使用功率补偿型差示扫描量热仪(DSC)对4种不同品牌的猎枪弹丸进行分析。结果可测得每种弹丸的DSC曲线和熔点温度Tm,熔融峰温Tmp,熔化焓ΔHm等热学参数。结论利用差示扫描量热法可以对不同品牌的猎枪弹丸进行鉴别,该方法为办案过程中遇到同号数不同品牌的猎枪弹丸鉴别提供了一种有效技术手段。     

Case report of a homicide by a shotgun loaded with unusual ammunition

Reported is the case of a man killed by a neighbor with a shotgun loaded with a unusual ammunition. The cartridge contained several shots chained together by metallic wires. Such ammunition has been used for hunting purposes but is now banned, so it can be handmade only. The joined pellets produce a wound with features that are different from those of a wound made by a regular load of pellets. Several interpretive problems are caused by the unknown number of pellets contained in the shell and the effects of the wire holding the shot together.     

Unusual motor ability in gunshot injury of the heart caused by a shotgun

In a case of shotgun-injury of the heart with complete rupture of both ventricles and lesion of the aorta the victim was able to move a few metres in approximately six seconds. Despite other opinions ability to move or act can be maintained in cases of severest injuries of the heart caused by missiles with high energy.     

Shooting distance estimation for shots fired by a shotgun loaded with buckshot cartridges

The present study was carried out to clarify the problem of shooting distance estimation, by studying shots fired with buckshot ammunition in 12 gauge shotgun.For this purpose, the pattern diameter (PD) and the distances between buckshot (DBB) within the pattern were evaluated.Experimental shots were carried out with three differently choked barrels: full, half and cylinder; Winchester-Western OOB and OB buckshot ammunition were used.The results show that the estimation of shooting distance, based on the present parameters, is scarcely reliable especially when this estimation must be calculated on the basis of only a few wound holes on which measurements are made.     

Tool mark striations in pig skin produced by stabs from a serrated blade

Stab wounds produced by serrated blades are generally indistinguishable from stab wounds produced by non-serrated blades, except when visible tool mark striations are left on severed cartilage. Using a pig-skin experimental model, we explored the possibility that similar striations may be left in skin. Stabs into pig skin were made using a straight spine coarsely serrated blade (121), a drop point finely serrated blade (20), a clip point irregular coarsely serrated blade (20), a drop point coarsely serrated blade (15), and as controls 2 non-serrated blades (40). Tool mark striations could be seen on the skin wall of the stab canal in all stabs made using serrated blades but in none with non-serrated blades.The striation pattern, reflecting the class characteristics of the serrated blade, was the same as that described in cartilage but less well defined. Fixation of the specimen with Carnoy's solution best preserved visible striations, and fixation with formaldehyde after staining with 5% Neutral Red was also satisfactory. Casting with vinyl polysiloxane dental impression material greatly facilitated photo-documentation. Applying the technique to homicidal stabbings may help identify stab wounds produced with serrated blades.     

根据霰弹丸分布图形推断射击距离的实验研究

目的 建立推断制式霰弹猎枪射击距离的数学计算公式和方法。方法 选用国产制式12号及16号猎枪,配用1号及3号猎枪弹,以1至12m距离射击实验靶纸,获得霰弹分布图形360例,将图形测量数据与实验距离进行数学理论分析。结果 建立6种不同枪弹种类推断射击距离d的计算公式,分别为12-1型(缩口)ss=-0.2+0.44d;12-1型(无缩口)ss=-0.94+0.63d;12-3型(缩口)ss=-0.59+0.52d;12-3型(无缩口)ss=-0.36+0.34d;16-1型s=-0.37+0.30d;16-3型s=-0.16+0.23d,并用Visual Basic5.0软件编制通用程序汇总软件。结论 本研究建立的方法简单实用,误差较小,可以用于推断制式猎枪的射击距离。