Captive bolt pistol

A captive bolt pistol or gun (also variously known as a cattle gun, stunbolt gun, bolt gun, or stunner) is a device used for stunning animals prior to .

The goal of captive bolt stunning is to inflict a forceful strike on the forehead with the bolt in order to induce unconsciousness. The bolt may or may not destroy part of the brain.

The bolt consists of a heavy rod made of non-rusting alloys, such as stainless steel. It is held in position inside the barrel of the stunner by means of rubber washers. The bolt is usually not visible in a stunner in good condition. The bolt is actuated by a trigger pull and is propelled forward by compressed air or by the discharge of a blank round ignited by a firing pin. After striking a shallow but forceful blow on the forehead of the animal, spring tension causes the bolt to recoil back into the barrel.

The captive bolt pistol was invented in 1903 by Dr. Hugo Heiss, former director of a slaughterhouse in Straubing, Germany.

Captive bolt pistols are of three types: penetrating, non-penetrating, and free bolt. The use of penetrating captive bolts has largely been discontinued in commercial situations in order to minimize the risk of transmission of disease.

In the penetrating type, the stunner uses a pointed bolt which is propelled by pressurized air or a blank cartridge. The bolt penetrates the skull of the animal, enters the cranium, and catastrophically damages the cerebrum and part of the cerebellum. Due to concussion, destruction of vital centers of the brain, and an increase in intracranial pressure, the animal loses consciousness. This method is currently the most effective type of stunning, since it physically destroys brain matter (increasing the probability of a successful stun), while also leaving the brain stem intact and thus ensuring the heart continues to pump during the exsanguination. One disadvantage of this method is that brain matter is allowed to enter the blood stream, possibly contaminating other tissue with bovine spongiform encephalopathy (BSE, colloquially known as mad cow disease).

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