Most CO2 guns use a disposable cylinder, called a powerlet, which is pre-filled with 12 grams of liquefied carbon dioxide. More expensive models can come with larger refillable CO2 reservoirs, like those guns used for paintball marker games.
They have 2 main advantages over pre-charged pneumatic air guns. First, they use a simpler and more compact system of energy storage, as a small volume of liquid CO2 can be converted to a large volume of pressurised gas. Secondly, they do not require a pressure regulator. This means that CO2 guns are more simply constructed than the other types of air guns.
However, they can be more expensive to use, as liquefied CO2 must be bought continuously, whereas PCP guns and hand pump models use "free" air, or at least “low cost” air when refilling from a diver's tank. Moreover, CO2 guns are generally less powerful and less efficient than PCP guns.
Because of their lack of power, many CO2 guns are pistols or semi-target type rifles, and are well below the energy limit for air rifles imposed in the UK, so can therefore be used without a licence. CO2 guns are thus commonly used for training purposes, as both the guns and ammunition are cheap and safe to use, and can be bought and owned in areas where firearms possession is strictly controlled, or even banned.
CO2 guns have also been used experimentally as a non-lethal law enforcement weapon, in a similar way to non-lethal shotguns, and their low velocity make them even safer for this purpose.
They have 2 main advantages over pre-charged pneumatic air guns. First, they use a simpler and more compact system of energy storage, as a small volume of liquid CO2 can be converted to a large volume of pressurised gas. Secondly, they do not require a pressure regulator. This means that CO2 guns are more simply constructed than the other types of air guns.
However, they can be more expensive to use, as liquefied CO2 must be bought continuously, whereas PCP guns and hand pump models use "free" air, or at least “low cost” air when refilling from a diver's tank. Moreover, CO2 guns are generally less powerful and less efficient than PCP guns.
Because of their lack of power, many CO2 guns are pistols or semi-target type rifles, and are well below the energy limit for air rifles imposed in the UK, so can therefore be used without a licence. CO2 guns are thus commonly used for training purposes, as both the guns and ammunition are cheap and safe to use, and can be bought and owned in areas where firearms possession is strictly controlled, or even banned.
CO2 guns have also been used experimentally as a non-lethal law enforcement weapon, in a similar way to non-lethal shotguns, and their low velocity make them even safer for this purpose.