Many parents and paintball newcomers email me regarding the differences between using CO2 and a High pressure or Nitrogen tank.  This guide will hopefully help you paintballers and parents that have questions.  You ballers that have been around a while, I'm not gonna tell you anything you don't already know here, this guide is being written to help out new paintballers.  This guide is just some quick facts about the difference, benefits and drawbacks of the use of these elements in paintball, you can research much deeper than this if you wish.

     CO2 is by far the most used "gas" in the paintball industry.  Paintball started on the small silver 12 gram co2 pellets and evolved into the refillable constant air tanks you see today.  You should know that co2 has three states, solid (dry ice), liquid and gas.  The reason a paintball co2 tank is measured in ounces (20 ounce, 12 ounce, etc.) is because your tank is actually filled with the liquid form of co2.  That liquid expands into a gas inside the tank, that gas form of co2 is what powers your paintball gun.  One of the reasons paintball guns fail in cold (about 50' or colder) weather with co2 is because the liquid inside the tank is not warm enough to expand into a gas.  Without enough gas being created inside the tank, the gun does not have enough power to recock or provide the velocity to propel the ball the normal distance.  The opposite occurs during hot weather.  The liquid expands too much, causing high velocity (called "shooting hot") or eventually the tank "blows" its safety burst disk.  This is the primary reason you should not overfill tanks or store them in intense direct sunlight or in a vehicle during the hotter months.  This is also the reason fields require you to continue to check your gun velocity throughout the day.  That brings us to the biggest drawback of using co2, its performance varies with the temperature.  Your guns range will vary, because your velocity will vary based on the temperature changes during the course of the game day.  You can also have "liquid" shots.  This occurs when the liquid co2 makes it into the gun itself, wasting several shots worth of co2 and usually causing paintball breaks in the barrel due to extreme velocity.  To prevent this, point or store your gun with the barrel upward when not playing. Handle the gun like there is water in the tank, because the co2 will flow due to gravity, similar to any liquid.  You can improve you guns performance with co2 by adding an expansion chamber (this allow the liquid another stage to expand before it reaches the valve), or a regulator (this prevents liquid and regulates the flow of gas).  Without these upgrades, your shots can vary as much as 30-40 feet per second which translates into large shot range variations, basically you only have a ballpark idea where the ball will go.  The final drawback to co2 is that it is actually more dangerous than high pressure.  Because the majority of the co2 in the tank is stored in the liquid state, it actually becomes a propellant if the valve or tank is ruptured, creating a flying metal projectile.  All the recorded deaths in paintball have been co2 tank related.  On the positive side of co2, it is readily available almost anywhere and it is inexpensive to use compared to its high pressure counterpart.  Let's review, co2 is not good in cold or extremely hot weather and the performance of you gun will be inconsistent based on the temperature.  It is however readily available and inexpensive.

     High pressure or Nitrogen tanks use compressed air or nitrogen, even hydrogen on some models, to cycle the paintball gun.  This type of gas is measured in PSI (pounds per square inch) because it is only used in its gas form in the paintball industry.  All guns have a minimum operating pressure, which means that when your gauge on your HP tank drops below that level, you are no longer firing at peak performance.  The big benefit of using high pressure in paintball is its consistency.  High pressure provides a constant power source that does not vary and is not affected by temperature.  Once set, your gun will shoot nearly the same on every shot in any type of temperature until it drops below its minimum operating pressure.  A well tuned marker will vary by only one or two feet per second using high pressure.  This means that your range will be very consistent and that your shots will go nearly the same place every time with the only major variable being the paintball itself.  Because of this, most players that have used HP have a hard time going back to co2.  The biggest drawbacks of HP is the cost of the tank and availability of filling locations.  While there are some lower cost HP tanks, in the $40-$50 range, to truly compete at a realistic level, you will need to spend about $150 on a HP tank.  Why are they so expensive ?  Firstly you are dealing with a lot more pressure that the co2 counterpart. Most HP tanks are 3000 or 4500 psi, that is a lot of pressure if you stop to think about it.  Consider that car tire has about 35 psi and that most home air compressors only go up to about 500 psi.  For this reason an HP tank must have an expensive regulator to bring that pressure down to a level it can be used.  Most quality HP tanks are carbon fiber wrapped for additional strength, but this of course means additional cost.  It can also be difficult to find a place to fill your HP tank as the cost of the filling equipment is substantially higher than co2.  In review,  HP equipment cost substantially more than co2 and in many areas HP tanks are harder to get filled.  However, its performance drastically beats co2 and you can play in any temperature without worry. 

     One final basic I will cover because of the number of emails I receive on the subject is tank hydro testing.  Primarily 24, 20 and 12 ounce flat bottom co2 tanks and and all HP tanks must be tested every three or five years depending on the tank.  Many players get angry when the tank cannot be filled, but you should be aware that it illegal to fill a tank past its hydro date and the fine can be over $10,000.  You begin to see why most fields and stores take it so seriously, not to mention the safety aspect.  The average cost to get a tank hydro tested is $30.00.  Usually it is not cost effective to hydro a co2 tank because you can buy a new one for the same or less, but most HP tanks are worth getting tested.  Most paintball stores have a program to help you get your tank hydro tested and for more information on hydro testing a good source is crossfireinc.com .  If you are buying a used co2 or HP tank on ebay or elsewhere you should always ask or verify the date on the tank to avoid getting stung with a tank that cannot be filled.

I have covered the very basics and I hope this has helped you in your quest to be a safer, yet more "lethal" paintball player.

Stay low and shoot quick !

Ron-ASP