Mechanical methods - Free-bullet firearms

When used properly, a free-bullet provides a quick and effective method of killing as it requires minimal or no restraint of the animal and can be used to kill from a distance. This is particularly advantageous when dealing with extensively managed, wild or agitated animals which may be dangerous in enclosed spaces, including adult bovines and deer. With a successful shot, death is immediate and there is no requirement for further bleeding or pithing of the animal.  This may be particularly useful when killing for zoonotic disease control, as it minimises handling and contact between humans and animals and prevents further disease transmission.

A free-bullet firearm, used from long range, should be aimed to penetrate the skull in a frontal position and proceed through the brain in to the upper neck, following the line of the vertebra. This will cause catastrophic injury to the mid-brain and brainstem leading to immediate death.  This method should only be used by properly trained and competent marksmen. The marksman should ensure the animal is stationary and in the correct position to enable accurate targeting. In the interests of safety, the field of fire must be directed away from any roads and houses; any essential accompanying staff must remain behind the marksman. All personnel present must wear protective clothing. Once shot, animals should be checked to ensure the absence of brainstem reflexes and death confirmed.

See the HSA online guide to Emergency Slaughter and Humane Killing of Livestock Using Firearms for more detailed information on the use of firearms. Information is available on firearms equipment, the correct shooting positions for different species and the operation, maintenance and safety of firearms.

Legislation controlling firearms differs across the world. Operators must ensure that they operate within the bounds of relevant national legislation. Contact your local authority for information before obtaining or using any firearm.

Positioning

In cattle, the brain is situated high in the head. The ideal point of penetration is in the middle of the forehead – at the crossing point of two imaginary lines drawn between the middle of each eye and the centre of the base of the opposite horn. This should give a position about 7cm, ±1cm, above a line drawn across the forehead at the back of the eyes. The shot should enter at right-angles to the skull as shown in Figure 5. When shooting bovine animals at range, the operator should be in an elevated position to ensure the correct angle of impact is achieved.

Figure 5: Correct positioning for shooting cattle with a free-bullet.  

When shooting deer it must be remembered that antlers do not equate to horns in cattle. The ideal aiming point is in the middle of the forehead, at the crossing point of two imaginary lines drawn from the middle of each eye to the top of the opposite ear. In stags, this spot is found between the antlers. As with cattle, the angle of the shot should be directed through the brainstem (Figure 6). When shooting deer at range, the operator should be in an elevated position to ensure the correct angle of impact is achieved.

Figure 6: Correct positioning for shooting deer with a free-bullet. 

Figure 7a: Correct positioning for shooting polled or lightly horned sheep and goats with a free-bullet. 

When shooting sheep and goats with a free-bullet firearm, the aiming point is on the mid-line, just above the eyes, directed down the line of the spine into the bulk of the body (Figure 7a). In practice this can be quite difficult to achieve and a slight error in the angle of shot, or minor movement on the part of the animal, can result in a free-bullet exiting from the animal’s head or neck. In order to get this right when using a free-bullet weapon, the animal’s head must be in the normal position.

Heavily horned sheep and goats can present a problem where a free-bullet weapon is used. The mass of horn over the forehead can leave little or no target area: a shot between the eyes is too low and should not be used under any circumstances. Such animals can be shot from behind the poll (Figure 7b). However, this is dangerous with a free-bullet weapon and, if undertaken, the animal should always be situated on soft ground. Where possible, a shotgun is recommended for this type of shot. 

Figure 7b: Correct positioning for shooting heavily horned sheep and goats with a free-bullet. 

Pigs are among the most difficult animals to shoot. There are two reasons for this: first, the target area is very small and this problem can be exacerbated by the ‘dish’ (concave) face shape of certain breeds and in aged pigs; second, the brain lies quite deep in the head, relative to other species, with a mass of sinuses lying between the frontal bone and the brain cavity. The ideal site for shooting pigs is one finger’s width above eye level, on the mid-line of the forehead, aiming towards the tail (Figure 8).

Figure 8: Correct positioning for shooting pigs with a free-bullet. 

Considerations when using firearms during depopulation due to disease control

Using a firearm to kill animals in this situation has a number of advantages and disadvantages.  The method is advantageous in situations involving animals which are wild or free-ranging and cannot be easily gathered or restrained. There is no need for direct human-animal contact which is beneficial for many reasons. For example, it prevents the passing of zoonotic diseases and avoids the handling of agitated or unpredictable animals which may pose safety risks. When performed correctly, the animal is killed instantly due to destruction of brain tissue, making it a humane choice.

However, this method requires careful consideration as there are some serious disadvantages associated with the use of free-bullet firearms. If used improperly there is a great danger to humans and other animals in the vicinity and there is the potential of non-lethal wounding. The destruction of the brain tissue may preclude the diagnosis of some diseases during a post-mortem examination and leakage of body fluids through the entry wound, nose and mouth may present a biosecurity risk. Legal requirements may prevent or restrict the use of firearms and, in some areas, there may be a limited availability of competent and appropriately licensed personnel.

To protect the safety of the animals and other people on site, the operator of any firearm must be fully trained and competent. It is very important the correct ammunition is used, otherwise animals might not be killed immediately and/or the operator could be injured. The use of firearms in enclosed spaces, or when animals are on hard surfaces, could result in ricochet of free-bullets and is to be avoided for health and safety reasons.

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