HPA vs. CO2
One of the most common questions beginning players ask is the difference between using Compressed Air (also referred to as Nitro, Nitrogen, N2, HPA or High Pressure Air) and CO2 tanks. In a nutshell, both provide pressure for a paintball marker to cycle and propel the paintball. However, both work on a different principle and sometimes only one can be used.
CO2 (Carbon Dioxide) was the first propellant used in paintball and set the standard for many years. For paintball purposes we use it in two types of vessels, 12 Gram Cartridges (used in paintball pistols such as the Tiberius and Miltec and stockclass pump markers like the Phantom) and refillable CO2 Tanks. These are filled with liquid CO2 which expands to create the pressure used for the marker. This pressure fluctuates due to elevation, temperature and other variables but the benchmark is 850 psi (Pounds per Square Inch).
Using CO2 has some positive advantages. The tanks tend to be smaller and lighter than HPA while yielding the same or more shots per fill. Facilities to have the tanks filled are generally easier to find as many gas/ welding supply and fire extinguisher shops have the means to fill your tanks as well as paintball pro shops. The number one reason for CO2′s enduring popularity is cost. The tanks are very cheap so a player can easily own several tanks, thus having plenty of air for a full day of fun.
CO2 does have its drawbacks. Because it is a liquid turning to gas it cools as it expands. This isn’t a big deal if you don’t shoot much but is very noticeable when shooting rapidly or a lot. The pressure begins fluctuating high and low with the result that your marker’s performance and accuracy begins to suffer. As the tank chills it begins drawing liquid CO2 up into the marker resulting in pressure spikes that can push velocities into unsafe speeds. If you see big white clouds of vapor coming out the muzzle and white snow falling out the barrel (its actually dry ice) when shooting you can bet that liquid worked its way into the marker. In cold weather the pressure can get so low that many paintball markers won’t cycle properly. Liquid CO2 is hard on the seals of your marker and can cause damage if it works it way into the solenoids of many electropneumatic markers. Thus many markers cannot use CO2. Always refer to your marker’s owners manual and if you’re still not sure then call us.
Sound frustrating? It can be. Thats why players started using Compressed Air (HPA). Originally pure nitrogen was used, which explains why its sometimes referred to as N2, Nitro or Nitrogen Tanks. Rather than filling the tank with liquid they are instead pressurized up to the tank’s rating of 3000psi or 4500psi. The pressure is then regulated through the tank’s regulator down to 850psi (High Output) or 450psi (Low Output). The beauty of HPA is that the pressure is much more stable than CO2 and changes due to shooting fast or playing in cold weather are barely noticeable. No thick clouds or snow from the barrel, no more layers of frost on the marker body and your accuracy improves due to better velocity consistency. Today’s electropneumatic markers were designed with these tanks in mind.
HPA has three drawbacks. In some remote areas getting tanks filled can be a problem (tire pumps and shop compressors do not work, they rarely go over 180psi). The tanks tend to be a bit larger and bulky compared to CO2. Lastly, they do cost more than CO2 tanks.
HPA is the better investment in the long run. The benefits over CO2 in all-weather performance are well worth the additional cost. Besides, an HPA tank is a piece of equipment that can transfer to any marker you upgrade to. Determine what your needs are for your equipment and level of play and choose accordingly.
Courtesy of Paintball-Online.com.