Regulators – What they are, what they do, and do you need one

Back to the home page...

In today’s world of low pressure markers and High Pressure Air (HPA), regulators are almost an afterthought. However, there are still many of us out there that run good old CO2 and markers that have never seen a regulator. So while those of you who had regulators come with their markers really may not have any questions regarding whether or not you need one you may learn more about what they do, why they are on your marker, and why they are a good thing.  For those that do not already have a regulator, read on to find out more about them and whether or not there should be one in your future.

Got Gas?

NOT that kind of gas…geeze.  So why spend money on a regulator?  To properly answer that question you need to know how a paintball marker works, how CO2 behaves, and how these things affect where your paintball goes when you shoot.

First let’s cover some paintball marker basics. All markers require a certain amount of air at a certain pressure in order to propel a paintball out the barrel at a given velocity.  An increase in pressure or the amount of gas used per shot will increase the velocity of the paintball.  In Spyder style markers, when you adjust the velocity screw to increase your velocity, what you are really doing is increasing the force with which the striker will hit the valve.  The harder the valve is hit (up to a point), the longer it will stay open.  The longer the valve stays open, the greater the amount of air passes into the bolt to fire the paintball and thus the increase in velocity.  It's a VOLUME (the amount of gas) change that increases the velocity when that screws is adjusted, not the pressure. Keep this in mind. 

All Semi-Auto markers will also require a portion of that air to be used to return the marker to a “cocked” state so it may fire the next round.  Markers designed to operate on CO2 can operate at very high pressures (with some exceptions).  I know this sounds very vague but we’ll tie it all in here in a moment.

CO2, as we deal with it in paintball, has two forms.  The first is a liquid. The second is as a gas.  It is the CO2 gas that we use to operate our markers and shoot the paintball.  However, in our tanks it is in its liquid form.  CO2 is more condensed when it is in liquid form.  Thus a small amount of CO2 liquid can expand into a much larger amount of CO2 gas.  Since our markers are designed to operate on a gas and not a liquid we have to have the CO2 change from the liquid form we store it in to the gas form we can use.

Just how is this done?  Two things are needed and can cause CO2 to change from a liquid to a gas.  One is an increase in area and the other is heat.  The first of these may be a bit hard to understand at first.  Let’s say you have a 20oz CO2 tank.  When you have your tank filled, they will only fill it to somewhere around 17oz.  This leaves a small 3oz area in the tank that will allow a small portion of liquid to transform into a gas.  However, since we usually mount our tanks horizontally on our markers this gas bubble is usually not near the valve of the tank until the tank is about half empty.  This is why some CO2 bottles are equipped with an anti-siphon.  And anti-siphon is a small tube installed in the valve that goes from the valve into the tank then makes a 90 degree turn upwards towards where this gas bubble will be when the tank is mounted on the maker.  This helps, but does not eliminate, the possibility of liquid CO2 entering the marker.

An expansion chamber can be installed on a marker to help keep the liquid CO2 from making it up towards the valve.  Without an expansion chamber, the liquid CO2 only has a very small airline in which to try and expand into a gas.  With the larger area offered by an expansion chamber, the liquid CO2 has a much easier time making the transition.  If you use a remote line, it also acts as an expansion chamber by giving the liquid CO2 more room in which to change into a gas.

Remember we also mentioned heat has a big role to play in the transition from a liquid to a gas too.  You see, in order for a substance to change from a solid to a liquid or a liquid to a gas it must have energy added to it in order to make the change.  With CO2, that energy is heat.  For a more “real world” analogy, think about water.  If you freeze it into ice (water’s solid form) and put it in a container at room temperature, it will start to turn into its liquid form.  Also, if you were to measure the temperature of the air around it you would see that the air temperature around it would drop.  This is because it is taking heat out of the air and using it to go from a solid to a liquid.  Now, if you apply more heat by placing that container on the stove, the water will begin to boil and change into water vapor, water’s gas form. 

CO2 works the same way but with different temperatures.  So let’s go back to that 20oz bottle again.  It has 17oz of liquid CO2 in it and let’s say it’s 50 degrees outside.  Now you don’t have it on your marker, it’s just sitting there and the pressure at the valve is 900psi.  Now let’s say the temperature starts to rise to 70 degrees.  The increased heat is going to cause more of the liquid to convert into a gas but the gas has nowhere to go.  However, gas takes up more room than liquid (remember we talked about a little bit of liquid turning into a large amount of gas?) thus the pressure in the tank may rise to say 1200psi!  This is why we have bursts disks on our CO2 tanks so that if the tank was filled to much or the temperature got to hot that the pressure buildup inside the tank wouldn’t cause the tank to bust…but rather the burst disk to rupture and save the tank.

Now, let’s say you have that same 20oz bottle and it’s sitting in 70 degree weather with 17oz of liquid CO2 in it at about 1200psi but now it’s connected to a marker.  When you take a shot, a number of things happen.  First, the air in the marker that is stored behind the valve for each shot is released into the bolt and, eventually, the barrel.  This lowers the pressure in that section.  Air from the line going from the tank to this area is at a higher pressure so it tries to equalize pressure between the two sections.  However, now the pressure in the tank is higher than what is in the line so it begins to feed gas into the line to equalize pressure between it and the line.  This lowers pressure in the tank and allows more room for more liquid CO2 to turn into a gas.  However, we mentioned that in order to do so the liquid CO2 requires heat to do this and the temperature outside hasn’t changed.  Thus the temperature around the CO2 bottle will drop a little bit as heat energy is drawn out of the air to allow the liquid to convert into a gas and fill up the space made by the marker using some of the gas to shoot a paintball.  The faster the marker fires, the more heat energy will be taken out of the air around the bottle for the liquid to keep up with the demand.  However, there is a problem.  As heat is taken out of the air around the bottle with each shot, this means that each subsequent shot has LESS heat energy in the air around it to draw heat from thus meaning it cannot convert as much liquid into a gas as the shot before it.  This means that the pressure in the tank will drop with every subsequent shot when they come in rapid succession.  This is why if you shoot a bunch of shots out of your marker very quickly your CO2 bottle gets REALLY cold.

This effect is what is called “shoot down”.  As the pressure in the system drops so does the velocity of your shot and thus your range.  Now the good news is obviously the air around the bottle will heat up again once you stop shooting. 

What this means for you though is that depending on how much you shoot, the setup you have, and the temperature at the time you are shooting your velocity will vary greatly if you are on CO2.  If it’s 60 degrees in the morning when you start playing but gets to 80 in the afternoon, your marker is going to shoot much higher as it gets warmer.  If you rip off thirty shots in quick succession be prepared for the later shots to drop short of where the first shots landed.

This is why when you operate on CO2 that even though you have not touched your velocity screw (remember that's a volume of air adjustment) your velocity still will go up and down as the pressure of the CO2 source goes up or down. You have regulated the volume of air that is entering your marker with your valve and velocity adjustment screw now it's time to regulate the pressure of the CO2 as well.

So what does a regulator do?

Regulators, simply put, take a gas under a high pressure and reduce the pressure to a lower one.  How they do it is also pretty simple.  I kind of mentioned this early but I’ll point out here that one basic principle of gases is that if you have a certain volume of gas in two different containers but connected containers the pressure will try to equalize in both containers.  Now if you were to release the pressure in one container, gas from the other container would try to fill in the other container and pressure in both containers would remain equal to one another but less than what you started with.

A regulator works off this principle.  While there are a couple of different regulator types they all work on the same basic principle. There are two chambers in the regulator.  One is the input chamber and the other is the regulated chamber.  These two chambers are connected by a path that can be closed off with a plunger (for lack or knowledge of a better term). This plunger is connected to a piston at the top of the regulated chamber.  This piston has a spring on the other side of it that can be adjusted to increase or decrease the pressure it exerts against the piston. The amount of pressure this spring exerts will be slightly less than the pressure of the gas in the regulated chamber.  Thus if the pressure in the regulated chamber is lower than the pressure of the spring, the piston moves down opening the plunger between the high and low pressure chambers to allow gas to flow from the high pressure chamber into the low pressure chamber.  Once the low pressure chamber’s pressure equals that of the spring pushing down on the piston, the piston moves back up against the spring and closes the plunger.  The image at left illustrates the operation of a moving base type regulator. (Image courtesy's Marker Animation page.)

Regulators?  We don’t need no stinking regulators!

So now that you understand how CO2 works in relation to your marker and the basic operating principles of a regulator we can get into whether or not you need a regulator.  Yes, you in the back you have a question?  What about HPA?  Well, in our discussion on CO2 you’ll note the major issues revolved around converting CO2 from a liquid into a gas, right?  Well HPA is stored as a gas already so we don’t have any of those issues.  But because of this you don’t get the benefit of the pressure remaining constant as you shoot because there is no liquid waiting to be converted into more gas. 

This is why HPA tanks are rated by capacity (as in 48ci or Cubic Inches) and pressure (aka 4000psi).  HPA tanks compensate for this lack of “gas renewal” by storing more gas under a very high pressure (hence the name). So as you shoot the pressure will drop from the fill pressure with every shot (though in very small increments).  Because your marker isn’t designed to run on 4000psi of air this pressure must be REGULATED down to a usable amount such as 850psi.  There are generally three kinds of regulators on HPA tanks.  There is a fixed high pressure (850psi or so), a fixed low pressure (450psi or so) and an adjustable which allows you to set the output pressure where you need it.  I could go on about the benefits of each but that’s not really necessary for this discussion.  Just know that all HPA tanks are regulated in some way. 

So, how do you know if you need a regulator?  Well technically the only people that NEED a regulator are those folks that shoot markers which cannot operate at the high pressures a CO2 tank can produce.  Most of these markers already have some sort of regulator on them to reduce the input pressure down to where they need to be.  Some have even gone so far as to require the user to use HPA tanks only and some even dictate what pressure that tank needs to be set at. Obviously if you are one of these users you already have a regulator and thus the question is moot. 

For the rest of you, a regulator is always an option.  There are, however, a number of benefits to having a regulator.  First and foremost is a more consistent air supply.  Properly set up (and we’ll get into this in a minute) a regulator will deliver air into your marker at a set and predictable pressure thus making each paintball leave the barrel at a much more consistent velocity.  Also, since you are not operating on the full pressure offered by the CO2 tank you have a bit of a “pressure buffer” that will help reduce the “shoot down” effect. The drawback to a regulator mainly is cost as good regulators don’t come cheap.

You can also set up your system to run two regulators.  If your marker shoots with a velocity variance of +/- 5 fps a second regulator could drop that to a variance of +/- 2.  Obviously two regulator systems are not cheap and it is up to you whether or not the extra consistency is worth the extra cost. 

So I want a regulator, now what?

Now you need to choose how you want your system setup.  What?  You thought you just needed to pick on and buy it now?  Oh no, there’s more to it than that.  First you need to determine how you want your setup.  Will you be shooting CO2 or HPA?  Are you running HPA and want to add a second regulator to further improve consistency? (NOTE: Dual regulator setups are harder to “dial in” but offer even more consistency than a single regulator setup especially on CO2 systems.)  Are you running a remote line?  Are you putting your bottle on the gun under the handle or vertically under the receiver?  Will you use an expansion chamber?  How much are you willing to spend?  All these questions need to be answered to determine which regulator will suite you best.

The general rule is the closer you have your regulator placed to the area where the gas is stored just in front of the valve the more consistent the regulated pressure will be.  However sometimes it is more convenient to mount the regulator somewhere else.  For instance, maybe you can’t mount the regulator right under the body of the maker and having it under the handle would be a better location.  Or if you run a remote line you may want to put the regulator inline between the coiled hose and the on/off valve so that you can have a regulated air source for any marker you use with the remote. Some markers will let you remove a gas through fore grip and replace it with a regulator pretty easily while others will not. So look at your marker and how you play to determine how best to set up your regulator.

Time to buy!

A good regulator like this Palmer's Stabilizer (Inline version) can make a tremendous difference if you are using CO2 as an air source.

For CO2 based systems the choice is actually pretty easy.  Palmer’s Pursuit Shop makes a regulator called the Stabilizer.  It is specifically designed for CO2 systems and there isn’t a better regulator for CO2.  If you run your bottle horizontally under your grip, the Stabilizer will not only regulate your CO2 but prevent liquid CO2 from entering the marker. I personally run a dual regulator setup on one of my markers with CO2 and both regulators are Stabilizers.  The first time I chronographed with this setup I had to check to make sure the thing was seeing each shot because it was showing the same velocity each time.  The other good thing about the Palmer Stabilizer is that they come in many different forms so no matter what marker you have or how you plan on setting up your system there is a Stabilizer that will work with it.  Note that this performance doesn’t come cheap but I feel purchasing any other regulator for CO2 is just a waste of money.

For HPA systems looking to add a second regulator to their marker your choices are a bit more diverse.  The Palmer regulators are still very good but you can get regulators that work just as well, are HPA specific, but cost less than the Palmer’s units.  Even if you already have a regulator that came with your gun you may be able to make it a bit more consistent by replacing it with an aftermarket regulator. 

Because so many factors may go into which HPA regulator is good for you I don’t want to specify any particular type.  Buying a regulator for you HPA setup is much like buying your marker…ask around and see what people are using, why they are using it, what they are happy with and what they don’t like.  Do a broad search to find the right regulator for you and go from there. 

I would advise that no matter what regulator you get though that you invest in a pressure gauge for it.  I wouldn’t say that you should always use the gauge but that you should have one so that if you need to troubleshoot your system you have it available.  On dual regulator setups it’s almost a necessity for the upstream regulator (the one closest to the tank) to have a gauge.

Okay, I got it…now how do I set this thing up?

I’m going to assume here that since you did your homework on how you wanted to set up your system and that you got a regulator that will fit into this system that the question of how to attach the regulator to your marker shouldn’t be an issue.  So let’s get into how to set up a regulator.

A quick word of advice here though before we start.  This guide is good for markers that are designed to run on CO2 and do not have a gas assisted feeding system such as the Tippmann Cyclone.  The Cyclone based markers generally need a higher pressure to operate the Cyclone feed.  I would suggest not dropping the operating input pressure feeding these markers below 800psi.  They can still benefit from having a regulator as CO2 pressures can be higher than 1200psi but the setup procedure I’m about to describe would not apply to them.

With that out of the way let’s get to it.  What you’re going to do is air up your marker with a full tank of CO2.  Then, lower your velocity adjustment screw so that it is set to its lowest possible setting.  Now fire off 10-20 shots.  You don’t need paint in the marker just yet so just shoot air.  If the marker operated as it should then lower the output pressure of the regulator and fire another 10-20 shots. Continue to do this as long as the marker continues to fire properly.  At some point though, the marker will refuse to re-cock itself.  At that point you want to increase the output pressure of the regulator a little bit, re-cock the marker, and shoot another 10-20 shots through it.  The gun may refuse to cock again even after a couple shots.  That’s okay.  Up the output pressure again and repeat this process.  Continue to do this upping the pressure in small increments until the marker once again operates normally. 

This is setting your marker to its optimum operating pressure.  Load up some paint and using a chronograph (and wearing a mask…ALWAYS wear a mask when dealing with a loaded and aired up paintball marker), check to see what velocity the marker is shooting at.  It should be around 220fps.  Now start turning up your velocity adjustment until you are shooting at your field’s specified velocity but never over 300fps. 

A dual regulator system would be set up the same way but you would start by setting up the downstream regulator (the one closest to the marker) as specified above.  Then attach the upstream regulator and set it to approximately 800psi.  Remember that the upstream regulator is feeding the downstream regulator.  If you set there pressures too close to one another you will have air starvation problems as the upstream regulator won’t be able to keep up with the demand of the downstream regulator under high rates of fire.  This means if your marker cannot operate at a pressure below 600psi you don’t need a second regulator for it. 


Well there you have it, regulators in a nutshell.  If you search the Internet there is a wealth of knowledge on regulators, the different types, and which ones will work for your system best. 

Good luck, and remember, it is all about having fun.

- Robotech

Back to the home page...