Paintball Propellants

The two most used forms of propellants for paintball are CO2 (carbon dioxide) and HPA (high pressure air).

CO2 is widely criticized since the introduction of HPA. There are arguments about CO2 causing a large number of problems since it gets so cold when changing from liquid to gas and can cause everything from o rings breaking to trashing your solenoid when it leaks into your marker. Another issue is the poor accuracy, when fired what is used is the gas in the tank, so if you fire to rapidly it will take some time for the liquid CO2 to evaporate and refill the tank pressure that was lost. With the constantly changing tank pressure your velocity will also be constantly changing creating the potential of huge losses in accuracy.

High pressure air, HPA, doesn't have to change from a liquid to a gas it is generally more consistent and therefore viewed as the superior propellant. Another advantage to HPA is how much easier and cheaper it is to fill. With a compressor that can go up the required PSI you can fill your tank all day or if you are out in the field it is very common to have a fill station. A fill station in most cases is a SCUBA tank and the proper receiver for the nipple on your tank. There are arguments against it of course as well. One of the main points is that it is stored at a pressure around 5X higher than CO2 and that you have to have a gauge on your tank, this means that the tanks are going to be more expensive and generally heavier. HPA is about 80% N2 and you will hear it referred to as Nitrogen as well. Back when HPA was first introduced it was used in a higher nitrogen base of up to 100% which you will not see very much today, but the name nitro stuck.

Most markers today will shoot CO2 or compressed air, but most high end markers only recommend compressed air.