Humane Killing Tools

Introduction

A livestock stunner (‘humane killer’, slaughterer’s gun, livestock narcotic device) is used in abattoirs, butcher’s shops and farms to induce immediate unconsciousness before slaughtering meat stock. The first stunning devices were constructed at the beginning of the twentieth century. They consisted of a simple barrel with a heavy flange or trumpet-like muzzle end, which had to be placed against the animal’s forehead; an ordinary cartridge carrying a bullet was inserted into the opposite end of the barrel and discharged by striking the firing pin with a wooden hammer. Since the bullets frequently caused accidental injuries, from the 1920s and 1930s onward an increasing number of butchers turned to the safer ‘captive-bolt’ stunners.
Nevertheless, in several countries such as Britain improved models of free-bullet slaughtering pistols are still used today (for instance the Greener slaughtering guns and the Webley 0.32 in veterinary pistol). The wounds inflicted to the skin by the Greener ‘Bell Killer’ resemble ordinary gunshot entrance wounds with a variable extent of powder marking, which either reproduces only the central aperture or the outline of the whole muzzle. When using light weapons such as the ‘Telescopic’ Greener a double pattern of blackening may be seen because of a tendency to bounce at the moment of discharge. The Greener ‘Safti-killer’ has a patterned muzzle surface in order to prevent slipping. The same is true for the Webley 0.32 in, which otherwise looks like a common pistol; at the distal end of the barrel just short of the muzzle there are two holes as outlets for the combustion gases, which produce corresponding soot deposition in contact shots.


Captive-bolt Humane Killers (Fig. 1)

This type of slaughterer’s gun consists of a cylindrical metal tube which serves as a guide for an inlying steel rod (‘bolt’), which has a diameter of 7-12mm. The bolt is driven by the explosion gases of a blank cartridge and propelled a few centimeters beyond the muzzle. The report is less loud than in shots from real guns.
Two makes of captive-bolt stunners. Top: Schermer type (mod. ME, cal. 10 x 11 mm, diameter of the bolt 12 mm); bottom: Kernertype (mod. 289, cal. 9 x 17 mm, diameter of the bolt 11 mm).
Figure 1 Two makes of captive-bolt stunners. Top: Schermer type (mod. ME, cal. 10 x 11 mm, diameter of the bolt 12 mm); bottom: Kernertype (mod. 289, cal. 9 x 17 mm, diameter of the bolt 11 mm).
The distal end of the steel rod is usually excavated (conically grooved) so that its front acts like a sharp-edged circular punching tool. The initial velocity of the bolt is rather low (~40-45 ms”1) compared with hand guns (~ 300 ms”1).
After firing, in most models the bolt is automatically drawn back into the barrel either by compressed air or by rubber bushes and/or by a withdrawal spring. This rebound mechanism also prevents the bolt from becoming a free projectile unless the device is manipulated before firing (e.g. by removal of the rubber bush and withdrawal spring). Therefore, injuries can only be inflicted from a short distance of less than the propelled bolt’s length (< 10 cm).
The muzzle plane of the captive-bolt humane killer may show two or four openings arranged symmetrically beside the central hole serving as outlets for the explosion gases which are partly drained off through diverging smoke conduits (Fig. 2). This applies to the German Kerner type and some other models (e.g. Dick, Rekord, Ursus, and Kuchen). The number and location of the additional openings essentially determines the smoke soiling pattern in contact or close range shots (paired or clover leaf-shaped soot depositions). In other models (for instance the Cash and the Temple Cox slaughtering guns from the UK or the Schermer type from Germany) the soot emerges only along the bolt’s guide so that the blackening from gunpowder residue may either resemble a ring of dirt encircling the entrance hole or cover a greater area in circumferential distribution. The extent of smoke deposition depends on the propellant (black or smokeless powder) and on the strength of the charge used.
The blank cartridges (Fig. 3) are loaded with smokeless or black powder and differ with regard to the caliber fitting into the chamber of the respective model (e.g. 0.22 in, 9 x 17 mm, 10 x 11mm). The strength of ammunition varies depending on the animal to be slaughtered. The manufacturers offer several sizes of charge distinguished by color markings on the base of the cartridge case (with the strongest ones meant for heavy bulls painted black or red).
Muzzle end of two captive-bolt stunners. Left: Kerner type with two opposite openings (outlets for the explosion gases; arrows); right: Schermer type without additional smoke conduits.
Figure 2 Muzzle end of two captive-bolt stunners. Left: Kerner type with two opposite openings (outlets for the explosion gases; arrows); right: Schermer type without additional smoke conduits.
Blank ammunition for captive-bolt stunners. Cattle-killing cartridges RWS 9 x 17 mm; the case mouth is sealed by crimping the metal and inserting a wax plug. The strength of the cartridge is designated by a green color marking on the base of the case
Figure 3 Blank ammunition for captive-bolt stunners. Cattle-killing cartridges RWS 9 x 17 mm; the case mouth is sealed by crimping the metal and inserting a wax plug. The strength of the cartridge is designated by a green color marking on the base of the case

Injuries from Captive-bolt Narcotic Devices

When stunning meat stock the muzzle has to be placed tightly against the forehead so that the whole length of the bolt enters the cranial cavity. Analogous to the veterinary application, in most human victims the weapon is fired in contact with the skin. Nevertheless, the entrance wounds lack all the classical signs of contact shots as known from conventional firearms. There is no muzzle imprint and no stellate splitting because the skin is not ballooned out by expanding combustion gases, which follow a free bullet but not a captive bolt. Consequently, only little, if any, soot is found in the depth of the entrance hole. The excavated distal end of the bolt causes a sharp-edged circular punch lesion with the diameter of the entrance hole being a little smaller than that of the bolt due to the skin’s elasticity. If the shot is fired at an oblique angle there is a unilateral sickle-shaped beveling of the corium indicating the bolt’s direction.
Humane killers with two or four smoke outlets on the muzzle end produce a characteristic soot pattern consisting of roundish or elliptic zones of blackening arranged in congruity with the respective openings. Variations in shape and location of these foulings point to an oblique holding of the instrument. In noncontact shots the smoke deposits become larger, but less intensive, with increasing distance and finally disappear. Interposed hair or garments covering the entry site may prevent the skin being blackened at all. As mentioned above, other kinds of captive-bolt instruments do not have any additional smoke conduits; in such cases the entrance wound is surrounded by a ring or a circumferential area of powder soiling. If the soot was wiped off in the course of surgical treatment, the affected skin areas tend to dry up producing a brownish discoloration.
The typical entry sites are regions of the body where only a thin layer of soft tissue overlies flat bones (forehead, temple, parietal and occipital region). When the bolt enters the skull, it produces a round hole, which is sharp-edged (‘clean-cut’) on the outer table and beveled-out (‘cratered’) on the inner table. The external aspect of the entrance hole almost exactly reflects the cross-section of the bolt, whereas the inner diameter of the bone defect is much larger. In shots fired at an acute angle the entrance in bone is oval-shaped and sometimes accompanied by semicircular frame-like fracture lines.
Due to the limited length of the bolt, in shots to the head no exit wound is to be expected. Of course there is no bullet left at the end of the wound track. Because of the bolt’s punching function the impact surface is forced into the depth of the brain. The punched-out skin and bone are thrust inwards and left there as a so-called ‘imprimatum’. The skin is nearly always a component of the imprimatum (Fig. 4) and must be regarded as bacterially contaminated and therefore infectious (Fig. 4). Apart from the skin and the bone imprimatum, other material from outside such as pieces of hairs and textiles may be pushed into the wound path. Despite its low velocity the bolt causes a remarkably wide wound channel owing to the large cross-section and the excavated front; hemorrhage results from mechanical tissue damage with disruption of vessels. In contrast to the extensive local traumatization there are no morphological signs of elevated intracranial pressure from temporary cavitation such as indirect fractures, cortical contusion and intracerebral extravasation away from the permanent tract.

Fatalities from Humane Killers

Most of the fatal injuries from livestock narcotic devices are suicides, which account for 85% of the published statistical figures. Though the number of accidents and homicides is comparatively small, the possibility of such incidents has to be kept in mind. In the German language literature there are reports on more than a dozen homicide cases with a high percentage of female victims. In contrast to this, the great majority of suicides are males, most of them butchers or farmers, familiar with slaughtering guns. The frequency curve attains its peak in the fifth and sixth decade of life.
(A) Distal end of the captive-bolt in a Kerner type slaughtering gun; the steel bolt is conically grooved. (B) Punched-out piece of skin from the depth of the intracranial wound path ('skin imprimatum'). (C) Histological section of a skin imprimatum showing a bacterial colony and black powder residues (arrow).
Figure 4 (A) Distal end of the captive-bolt in a Kerner type slaughtering gun; the steel bolt is conically grooved. (B) Punched-out piece of skin from the depth of the intracranial wound path (‘skin imprimatum’). (C) Histological section of a skin imprimatum showing a bacterial colony and black powder residues (arrow).
The most common sites of suicidal entrance wounds are, in decreasing order of occurrence: the forehead (Figs 5 and 6), the temple, the parietal and occipital region, the precordium and the mouth. Some individuals use two or more different methods when committing suicide, for example by placing a noose around the neck before shooting themselves in the head with a livestock stunner. Some authors have even described suicide by repeated cranial shots from captive-bolt humane killers. Such observations prove that bolt injuries of the brain are not necessarily followed by immediate or persistent unconsciousness, if the bolt does not strike a vital area of the brain. Despite severe damage to the frontal and/or temporal lobes the individual may be capable of reloading the humane killer and firing a second time.
Contact entrance wound froma Kerner type captive-bolt livestock stunner in the central forehead of a suicide. The initially circular skin hole is partly held together by a surgical stitch. The entrance wound is accompanied by two roundish soot deposits corresponding to the openings of the smoke conduits.
Figure 5 Contact entrance wound froma Kerner type captive-bolt livestock stunner in the central forehead of a suicide. The initially circular skin hole is partly held together by a surgical stitch. The entrance wound is accompanied by two roundish soot deposits corresponding to the openings of the smoke conduits.
(A) Skull-cap of a suicide who shot himself in the forehead with a captive-bolt stunner. The punched-out entrance hole is located in the frontal squama. (B) Internal aspect of the skull showing a cone-shaped crater that is appreciably larger than the diameter of the bolt.
Figure 6 (A) Skull-cap of a suicide who shot himself in the forehead with a captive-bolt stunner. The punched-out entrance hole is located in the frontal squama. (B) Internal aspect of the skull showing a cone-shaped crater that is appreciably larger than the diameter of the bolt.
In fatal cases the survival period varies widely and may last up to several weeks or even months. The mortality has decreased, thanks to the great progress made in neurosurgery and intensive care, but in general the prognosis is still rather poor, though a recent clinical study reports a survival rate of more than 50%. In addition to extensive brain damage and intracranial bleeding from lacerated vessels, inflammatory complications such as pyogenic encephalo-meningitis or a cerebral abscess may be the cause of a delayed fatal outcome.
Suicidal injuries from captive-bolt humane killers are almost always contact shots. In most cases the shooting device is found close to the deceased. The hand holding the muzzle end often reveals soot on the radial surface of the index finger and on the ulnar surface of the thumb. Other visible soot deposits may be transferred to the hands in the course ofloading. In suicides firing again after the first shot the hands and the weapon are usually soiled with blood pouring from the entrance wound in the course of reloading.
The relatively small number of homicide cases is probably due to the limited length of the bolt which does not allow shots from a distance of more than a few centimeters. Most victims are, therefore, either defenseless or unaware of an attack.

Stud Guns

In this context powder-actuated fastening tools are only mentioned insofar as it serves to distinguish between stud guns and humane killers. Stud guns are similar to ordinary firearms and use blank cartridges to fire pins, threaded studs, nails or fasteners into wood, concrete, masonry or metal structures, so that other materials or objects may be affixed to the receiving part. The blank cartridges range in caliber from 0.22 in to 0.38 in and are loaded with fast-burning propellants. The external appearance of a stud gun resembles a large pistol with a flat face plate attached to the muzzle, which has to be pressed firmly against a solid surface before it can be fired. The purpose of this built-in safety mechanism is to prevent free flight or ricochet of the stud. Nevertheless, numerous accidents and a few suicides have occurred with stud guns.
Amajor cause of injuries and deaths is perforation of flimsy walls with the result that a worker behind or a bystander is struck by the nail. Many accidents are due to ricochet of the steel missile which as a result becomes bent. Thus the finding of a bent nail on radiographs of the victim can be helpful in determining the circumstances of the accident. In suicides, the most common sites for a stud gun entrance wound are the chest, the forehead, and the temple.
The morphology of skin wounds from studs is variable, e.g. a distance shot with a straight and pointed steel missile causes an inconspicuous slit like puncture wound, whereas a bent stud after ricochet produces an irregular, jagged laceration with abraded margins. In (suicidal) contact shots stellate entrance wounds surrounded by muzzle imprint marks have been observed.

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