CO2 Cartdriges 

Carbon dioxide is non-flammable and, under atmospheric conditions, it is chemically stable and inert. It can dissolve in water to produce carbonic acid, which acts as a relatively weak acid and has corrosive effects on steel and some metals.

CO2 cylinders for air rifles contain carbon dioxide mixed with a small amount of oil pressurized in liquid form.

Due to the presence of liquid CO2, igniting it rapidly cools the cylinder, similar to what would happen with a CO2 fire extinguisher.

These CO2 pistols and revolvers use carbon dioxide as a source of pressure. Once inside the pressurized container, some of the CO2 transitions into the liquid state, with both liquid and gas remaining within the container.

When the shooter pulls the trigger, a valve inside the cylinder opens, allowing some of the gas to pass into the barrel, causing a sudden and explosive pressure drop that propels the projectile through the barrel at high speed. Almost instantly, some more liquid goes through the same process to replace the previously released gas, preparing the cylinder for the next shot.