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A flare gun is a firearm that launches flares. It is typically used for signalling, as distress signalling, for people at sea or from the ground to aircraft. It is not designed to function as a weapon.

The most common type of flare gun is a Very (sometimes spelled Verey), which was named after Edward Wilson Very (1847–1910), an American naval officer who developed and popularized a single-shot breech-loading snub-nosed pistol that fired flares (Very flares). They have a single action trigger mechanism, hammer action, center fire pin. Modern varieties are frequently made out of brightly colored, durable plastic.

The older type of Very pistol, typical of the type used in the Second World War, are of one inch bore (26.5mm), now known as 'Calibre 4' for signal pistols. These are still available and more recent longer barrel models can also fire parachute flares. Many newer models fire smaller 12-gauge flares. In countries where possession of firearms is strictly controlled, such as the United Kingdom, the use of Very pistols as emergency equipment on boats is less common than, for example, the United States. In such locations, distress flares are more commonly fired from single-shot tube devices which are then disposed of after use. These devices are fired by twisting or striking a pad on one end, but the contents are otherwise similar to a round from a flare gun, although the flares themselves are much larger and can burn brighter for longer.. In the Russian Federation, which also has strict controls on firearms, a special tube-shaped flare launching device called a "Hunter's Signal" (Сигнал Охотника) is available. This is reusable but is deliberately designed in a way to avoid resemblance to a gun.

Flare guns may be used whenever someone needs to send a distress signal. The flares must be shot directly above, making the signal visible for a longer period of time and revealing the position of whoever is in need of assistance.

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