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· Super Moderator
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Discussion Starter · #1 · (Edited)
Hey everyone, I am going to talk about Airsoft gas and external gas rigs.

Lately I have seen a number of questions related to gas guns here and outside of the internet. So I am going to put this together in hopes that it helps everyone understand gas and external rigs a little bit better, and educate those that don't know squat about gas.

Lets start off with what gases are in use. I am going to start off with the lowest pressure and go up.

HFC134A (R134A), Duster Gas (HFC152A, HFC143A, HFC134A) - These are "low pressure" gases designed to run in plastic slide pistols. 134a: [email protected] 30c/86f=96.99

HFC22, Green Gas, Top gas, Propane - These are the most common gas in airsoft currently. Most notable is the green gas and propane. Propane: [email protected] 30c/86f=141.77

Yellow gas (MAPP, MAP//Pro, Proplylene) - MAPP gas, Discontinued as of April 30, 2008. MAP//Pro and Propylene (which are the same). Proplylene: [email protected] 30c/86f=174.54

Red Gas and Black Gas - These 2 I dont have any data for as I can not find much on them. From what I have found out is that red gas is quite a bit stronger then green gas. Black gas is apparently even stronger then red, supposedly anyway. From what I have gathered with the addition of CO2 and HPA into the sport, these two for the most part have been phased out.

Addition: Well I thought it was phased out...

Red Gas-
According to wikipedia, red gas is HCFC-22, and it seems to be illegal in some places(US).

The pressure of red gas(HCFC-22) is about 132 PSI.
Propane, which is the main ingredient in green gas, is about 124 PSI(Green gas is a bit weaker then propane, as it's a mixture).
And propane has been known to be too much for some guns.

You made me look something up, and I learned something new... Shame on you!

Edit: It might be alright, if the weather is very cold.
But the consequence, of leaving it in the gun in room temperature, is a unknowen factor, as it depends on your gun being able to handle the pressure.
CO2 - This gas is the next most common gas in airsoft. It is a very versatile gas. It powers pistols, grenades, rifles, and more. CO2 has an output pressure between 800-1200psi depending on temperature. 1200 is when the designed safety devices fail and vent the gas in order to insure no catastrophic vessel failures occur. In other words it keeps the canister from exploding.
CO2 comes in a variety of containers, ranging from 8gram cartridges up to 50 lbs cylinders (which weigh approx 200lbs). This gas is also cheap.

Thus far all of the gases I have listed are all liquid gases. I refer to these as "dirty" gases. I will explain why.

Source: Gas duster - Wikipedia, the free encyclopedia
When the top is pressed down to open the valve, gas flows out through the nozzle. The pressure inside the can therefore drops, and is no longer sufficient to keep the contents as a liquid; so some of the liquid boils, until the equilibrium pressure is re-established. The vaporization of a liquid is endothermic; thus, heat is absorbed, the temperature can reach −50 °C (−58°F), and the can becomes cold.
Continued use over a short period of time results in the reduction of the can's temperature. As the temperature drops, the vapor pressure of the liquid also drops, resulting in decreasing force of the gas at the nozzle. When the force of the ejected gas at the nozzle is insufficient to accomplish anything useful in terms of dust removal, and the temperature of the can reaches the boiling point of the liquid (that is −25 °C (−13 °F) for difluoroethane), the liquid no longer evaporates into gas in any useful quantity. The can must then return to room temperature before it will again provide sufficient gas flow. Alternating between two cans (allowing one to warm while the other is being used) is one way to work around this problem during an extensive dusting job. Warming the can with a heat source can be dangerous as the can may overheat and explode.
A related category of product has an internal dip tube that reaches to the bottom of the can, so it sprays the liquid. It evaporates very quickly, chilling items it touches in the manner that dry ice (solid CO2) would. These "chill spray" cans are used to troubleshoot malfunctioning electronic equipment.

This is referred to as Cooldown. All liquid gases do this.

I hate liquid gases, the reason is because of the endothermic reaction. This has destroyed more orings and seals in my paintball equipment then I care to calculate. The same thing happens in airsoft gear as well.

The last gas I have for this list is HPA, or High Pressure Air. As far as consistency goes, all gas guns that are not powered by HPA are unregulated. Which means the pressure of the gas going into the barrel is what ever. Which gives you massive jumps in FPS.

HPA needs regulation. Seeing as it is just compressed air in a bottle at high pressure (3000-5000 psi depending on tank.) All tanks used in airsoft are paintball tanks which have a regulator to bring the output of the tank to 850psi, or 450psi if you get one with a Low Pressure reg on it. HPA is not affected by cool down as it is not a liquid, it is also not affected by ambient temperature.

Most tanks come in 2 pressures 3000 and 4500psi. There are others but those are rare. Tanks also come in a variety of sizes as well as pressure. The size is in Cubic Inches, or CI. Sizes range from 13ci to the massive 144ci. Clearly the larger the ci the bigger the tank is.

Addition: You remember how I said that liquid gases were "dirty" well HPA can be dirty as well. Literally dirty, as in dirt and dust. Some fields have compressors that do not have filters, which allows for dirt and such to enter the tank. Something to keep in mind should your P* act up when you filled your tank from a dusty, dirty field.

A note on HPA tanks. All HPA tanks need to be re-certified every few years. For the aluminum tanks (also known as "steelies" due to their weight) is every 3 years. While the fiber wrapped tanks are every 3-5 years. This is merely a general rule of thumb, you need to check on your tank the exact details for hydrotesting. Addition: Examples of hydrotested tanks.

Also make sure they have the proper markings for your country, US D.O.T stamped, EU PI stamped, everywhere else I think is TC stamped.


When paired with a good regulator or 2. You can lower the pressure down to 60-135psi, the pressures that are used in most high end paintball guns and p* systems. I will get into this next.

Ok. Now its time to get into Regulators.

How does a regulator work? Here is the answer.

Source: Regulators Explained:

In today's high-tech world of paintball, almost all of us use a pressure regulator of one kind or another. One of the first in the industry was, of course, the AIR valve in the Automag, introduced almost a decade ago. Now, we have multi-stage "pressure balanced" HP nitrogen systems, inline regulators, more paintguns have regs as part of the operating system... the list is endless.

So how do they work?

First off, in the very basic design, the pressure regulator is essentially a spring-loaded check valve. Fig. 1 shows a simple, basic regulator. This design is used, in one shape or another, in the Automag line, Air America's HPA systems such as the Raptor and Apocalypse, and even the ANS 'JackHammer' pneumatics reg for the Autococker, among several other applications.

Fig. 2 shows an RG-1 type reg design. The concepts are essentially the same, but for simplicity's sake, the majority of this article will be in reference to the fig. 1 system.

In this example, lets start with the 'adjuster' backed off, so there is no tension on the 'reg piston'. What is happening here is, the high pressure (supply) air is pushing the 'reg seat' against the 'seal'. This seals the HP air from escaping, and probably getting into trouble somewhere.
This seal is made, because the 'supply' air is at a higher pressure than the 'output' air, which keeps the seal shut. So now, we crank down on the 'adjuster', which begins to put mechanical pressure on the 'reg seat'. However, the 'supply' pressure is still greater than the spring pressure against the 'seat', so it remains closed.
But if we keep cranking down on the spring, eventually the spring tension will overcome the 'supply' pressure, and force the seal open. So now, air is allowed to flow between the 'seat' and the 'seal', and begins to fill up (pressurize) the 'downstream' side of the reg. (Toward the gun, assuming nothing leaks.) At a certain point, because the 'reg piston' is in a sealed area on the 'low' pressure side of the reg, the additional pressure in the downstream side also begins to push on the reg piston, helping the supply air pressure force the reg seat closed.

This is the tricky part. Assume the 'supply' air is X psi. Assume the output (or downstream) side rests at less-then-X psi. Once you start cranking down on the 'adjuster', the spring pressure on the 'reg piston' gradually forces the 'seat' open, allowing the 'supply' pressure to flow to the 'output' side. This begins to pressurize the output side, which in turn begins to push against the 'reg piston' against the force of the spring. At some point, the supply pressure against the 'reg seat' and the pressure against the 'reg piston' from the output side overcome the spring's pressure and force the seat closed again. At this point, everything is in a state of balance.

Now, do something stupid like fire the paintgun or crank down on the adjuster harder, and things happen all over again.

When you fire the paintgun, that reduces the pressure in the 'output' side of the reg, so that the spring tension can again force the 'reg seat' open. This allows a small burst of air back into the output side, and as soon as pressures equalize again, the reg seat closes. (This is known as "recovery" and faster recovery is better, to prevent velocity drop during rapid fire.)

Or, in the other example, you crank down on the adjuster, which adds spring pressure which forces open the 'reg seat' again. And again, the seal allows a small volume of air through, and as soon as pressures equalize again (This time at a higher pressure) the 'reg seat' closes again.

The action of the reg seat opening a fraction of an inch and repressurizing the output side happens each and every time you fire the paintgun or alter the velocity. The reg could also be having to constantly work very slightly if your system leaks, as it tries to maintain downstream pressure.

Now, this is a very simple, basic description of how a regulator works. There are a lot of other factors to consider, such as how the loss of the 'supply' side pressure can increase the output pressure. Once the tank pressure drops, it becomes easier for the spring to push the seat open,and
that's the equivalent to increasing the spring pressure, so the output pressure rises, even though the adjustment is unchanged. Also, as most 'Mag owners will testify, the condition of the reg seal can become critical; if the seal/seat leaks, there is nothing to stop the full tank pressure from passing through to the rest of the gun. A dangerous situation in some cases. (That's why HPA systems have burst discs on the output side.)

There are quite a few different designs of regs in Paintball, though most can be classified as one of two types: The most common type has the adjuster vary the tension on a spring, which acts on a reg piston and seat, against a fixed reg seal. This design is used in UniRegs and Automags, among others.
The other design has the adjuster press directly against the reg piston and movable reg seal, which acts against a "fixed" spring pack. This is the basic design of the RG-1, Angel foregrip reg and WGP reg.

There is, of course, far more to pressure regulator technology than this little article can hope to cover. But the basics are here, and hopefully, this will help you to better understand the inner workings of most regulators.

Ok, now that that you know how they work you should understand why they are a big deal.

I use the term Recharge instead of Recovery. When looking around for a good regulator setup Recharge rate is important. Mostly for those with P* systems and the like. As Doc said, the better the recharge rate the better the reg. This is true, but it is not as vital in a sniper rifle, but if you use your rig for different systems then it will be.

Now as far as setups go, dual regulator setups are generally better for sniper setups then single reg setups. Especially with CO2. Dual regs allow you to "dial in" your fps better then a single. They also do a better job regulating the airflow over a single. On average, of all the signle reg setups I have seen and worked on I see an average FPS difference from shot to shot of about 5-7 fps.

Most dual regs I have seen and worked on have a FPS difference of maybe 1 fps at most, in one case 5 fps due to old grease and gunk buildup.

From my experience, some will argue this but I know this as fact, all regulators have a break-in period. The actual amount of time for this break-in varies from reg to reg and brand to brand. There are far too many factors to account for when dealing with break-in time so I am not going to get into that. DO NOT ASK ME "How long will it take to break-in BLAH reg?" I AM GOING TO IGNORE YOU. Just getting that out of the way.

Now most regs were built for HPA in mind, not CO2. Just be warned that not all regs handle CO2 well. All of Palmer's Pursuit regs will handle CO2 just fine for the most part, may need more maintenance ever so often, but that comes with the territory of using CO2.

Not all regs are maintainable. These are normally the cheap ones. Make sure you buy a reg that is rebuildable. This will keep you from having to replace your reg every time they break. Yes regs do break down from time to time. Most rebuild kits are cheap compared to the price of a new reg.

I will add more to it later, for now I am going to go get more burn cream...
Let me know what else you guys want to know, I will add it to this.

· Super Moderator
4,222 Posts
Discussion Starter · #2 · (Edited)
So you are wanting to convert your KJW. Well there are a few things you will need to look at first.
What gas are you going to use? HPA or CO2 capsules?
A few things you need to consider prior to picking your gas is:
Play style- How much do you shoot? A lot, a little?
Availability- Not all places fill HPA tanks, the closest place that fills them could be an hour+ away from you. While you can grab 12gs from your Walmart, 2 min from your house.
Positioning/Mounting- Where are you keepingyour gas system? on your back? in a rifle stock pouch? In your butt... stock? (lol, sorry couldn't resist.)

Is that everything? No, those were just some of the more important things I came up with. There are others but we will cover those when we get to them.

Either way you will need a regulator. As I said above, not all regulators handle CO2 well.


We are going to start with CO2, as it is the easiest with only 1 good option. Palmer's Pursuit Shop. They make THE BEST CO2 regulators. Are there other options? Probably, are they as good? Doubtful. The performance of their regulators are almost legandary, and are considered the gold standard for co2 powered paintball.

A Pamler's reg with a CCI quick change adapter is pretty much all you need. I will list some example setups later on.

Let's move on to HPA...
This may get a little confusing for some of you, but I will have some example setups later and explain why I chose the parts.

First lets start off with what you should not buy, this: BUILD-A-RIG - Amped SLP Air Rig

These were built for hobby/home shop air compressors. These also require you to use a SLP tank regulator. The reg is only $20, this should be a massive red flag right there. Why would you spend the money on high end barrels and buckings and what not just to skimp out on one of the most important things that will dictate how good or piss poor your shots are going to be? It just does not make sense to me why you would.

For those of you that have made this dumb choice, fear not! We can fix your uninformed choice for your air regulation needs! Luckly it will not be too expensive to fix. Well... It can be, but you have a good majority of the parts you will need already from your existing setup.

I'll come back to this later, for now we are going to move on to better options.

I have stated that the Palmer's regs are not the greatest on HPA as there are better options, but they will perform well enough. You can clean up the Palmer's by using a Dual Regulator setup.

Some other options are the Ninja LPR/Firebase, Dye, CP, and AKA. The last 3 you will need to assemble the rig your self. We will get to that later.

Ninja Paintball, they make some stellar gear and they have been doing so for just as long as Palmer's Pursuit. Also FYI Ninja builds the Firebase for Redline as a private label item, if you rip them apart they are almost the exact same.

The Dye Hyper3 is a pretty good reg as well as the CP regs, AKA 2-liter+ and the SST are solid performers as well.

Tank regulators:

The tank regulator is also important, not as quite as much as the main regulators I mentioned above, but you can squeeze a little bit more performance out of your setup if you pay attention!

Ninja is going to spotlight this section too. The Pro V2 tank valve is a pretty hardcore line. Fully rebuildable, and you can adjust the air pressure coming out of the tank to some extent. They sell additional bonnets in case you damage the one you have. Which you probably will. I have not used the Pro V2 yet, I will pick one up at some point and compare it to the Dye Throttle I have.

The Dye Throttle tanks are also quite good. Excellent airflow. Not rebuildable or adjustable. (to my knowledge)

CP used to be top dog for a while, but are still a good tank reg.

I am just going to say this now, just go with the Ninja tank reg. Just get the standard Pro V2, NOT THE SLP OR SHP.

Here are the owner's manual, the addendum to the owner's manual, Installation guide, fill valve assembly replacement guide, and the burst disk replacement guide.

For those with an SLP you can buy a new tank reg and replace it if you wish.
Here is a link, Ninja Paintball Pro V2 Regulator - 4500 psi - 450-800 psi Adjustable Output - Lowest Price Available from


Ok now for the section everybody is waiting for! THE EXAMPLES!! YAY!! All hardware is 1/8 NPT, I will not add the hardware unless needed, lists will get too long and junky. These are things I would do and recommend people.

Notes: P* run with the Foster 2 Series couplers. ASA threads are .825x14


Ex.1: In stock installation, or external rifle stock pouch. Basic build.

KJW marco line kit

CCI 12g quick change

Ex.2: Advanced build.

12g CART regulator

PPS ASA to 1/8 NPT

1/8 NPT female coupler


Ex.3: Hardcore

This is the rig I am more then likely going to run or something very close to it, myself when I get my gas rifle. This is designed for both CO2 and HPA.

Female Stabilizer


1/8 NPT ball valve

CCI 12g adapter


Plus connectors and other bits.

I will come back and finish the HPA section in a bit, I am really tired and spent all weekend looking up info for this. Enjoy what I have done so far. :shot:

· Super Moderator
4,222 Posts
Discussion Starter · #6 · (Edited)
I have never heard of anyone using MAPP in airsoft, but I guess it is possible. I will add it later. After I get some better details on it.

· Super Moderator
4,222 Posts
Discussion Starter · #9 ·
added MAPP, MAP//Pro, Propylene.

@timmah - I do not question your results, but I think you may be using MAP//Pro instead of actual MAPP.

· Super Moderator
4,222 Posts
Discussion Starter · #20 ·
I will make an amend to that, my PE tank is a 5 year: manufacturer is Luxfer.

A1 fire and safety said aluminum tanks are 3 years, they do hydrotesting for my local PB shop. This is also what my PraxAir rep told me as well. I will double check next time I go by either one.

· Super Moderator
4,222 Posts
Discussion Starter · #21 ·

Nope not this time! I added more important info!

Well I finally got around to updating this, and glad I waited. Lots of stuff has come out sense I wrote this and it seems HPA rifles are becoming more popular. Yes I know some of the numbers in the first post are off. I'll update those in a bit.

Right now I have about 6 firefox windows open with about 50 or 60 tabs on each. I have started loosing track of what is what. I will finish it up at some point this week hopefully. Right now I am on break. Here is the link to the updated post.

· Super Moderator
4,222 Posts
Discussion Starter · #22 ·
Well, I am sure most of you know you just can not fill an HPA tank off a home compressor...

This is a very accurate statement, like all things it has an exception. This is that exception. (or device similar to it)

Home << ShoeBox Compressors - The World's Smallest & Lightest 4500 PSI Compressor

I know it says "compressor" in it, and it is a compressor, and at the same time it is not.
This is a 2nd stage booster. It takes the 85psi input from your home OIL-LESS compressor and boosts it up to 3000-4500. (model dependent)

With a price tag of $700 USD for the base model and $1150 for the Freedom8, it's an option for those who do not have fast access to HPA filling capabilities. Speaking of speed, this thing lacks it big time in the time to fill department. The time it takes to fill a 68/4500 tank, take roughly 2 hours, and for a 88/4500, 4.4 hours. (used the math formula here: Performance | Typical Fill Times << ShoeBox Compressors - The World's Smallest & Lightest 4500 PSI Compressor using the Freedom8)

· Super Moderator
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Discussion Starter · #28 ·

· Super Moderator
4,222 Posts
Discussion Starter · #30 ·
High pressure low volume is essentially using a small amount of air at a high pressure. Pretty much what you normally see in airsoft. Low Pressure High Volume is what you see in polarstars and the like.

As for what goes on in the barrel is hard to say, as the people who claim to know refuse to post up the data. I honestly don't know.

My best guess is that with HPLV it can possible lead to the bb bouncing around the barrel due to the high pressure, but the low volume would mean that you are relying on getting the bb out of your barrel by force of the air pressure . While LPHV should not bounce the BB around as much, due to the lesser force used, and with the large amount of air behind it it should be more stable.

Again, that is theory.

· Super Moderator
4,222 Posts
Discussion Starter · #31 · (Edited)
I just had my tanks Hydrotested and I am going to post pics showing what to expect from it.

First up is my Fiber Wrapped tank.

Now the Aluminum tank.

· Super Moderator
4,222 Posts
Discussion Starter · #34 ·
Gas source cleanliness

Something I have failed to talk about is how clean your source gas is. Actually I apparently did a very small amount...

This is something you can not really control, but you can take into consideration when filling/buying your gas. This is mostly for HPA and CO2, but I would imagine that it is the same for others as well to some extent.

Take this with a fair amount of marketing wank, How to Pick Good Quality CO2 for Your Airgun

Yes, different brands have different levels of cleanliness to them. This grossness will eventually make its way into your gun. (depends on the brand and contaminant) You will need to clean your gun out sooner or later. Same with your regulators. If you are super active and shooting a lot then you will want to clean your gun a little more often then the guy who goes maybe once a month.

· Super Moderator
4,222 Posts
Discussion Starter · #35 · (Edited)
Speaking of CO2... Lets talk about something that not a lot of you may know about!

That being the Piercing Pin/Valve. There are a lot of different designs to do the same thing. Over time yours will deform and perform worse and worse. This is just how it goes, it is a sacrificial part.

Unfortunately it can be difficult to find replacements. I think Palmer's has them, you need to call them for them I believe as all they have on the site is the seal ring. (Also important as those fail before the pin does, or falls off and gets lost.)

I have found a few places that sell them, but most are all the same. This one is different...

I am going to order a few and test them out. If they perform as advertised then this would be a welcomed upgrade over the ones I currently have installed in a few of my other guns.

Or not... $27 in shipping... ridiculous.
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· Super Moderator
4,222 Posts
Discussion Starter · #36 ·
So... this happens.

This is a real danger for those in areas with hot weather or if you stage out of your car. Do not leave your gas in high heat environments. Yes, this includes your HPA bottles, and CO2. Your green gas/red gas/any other gas that use the same style bottle, lack the safety blow offs like your HPA tanks and paintball co2 tanks have. (Burst disks...)

People make fun of me for storing my gas, bbs, and batteries in a (highly) modified ice chest that has a large steel ammo box bolted into it... I am sure people will quickly stop laughing and realize the genius of my crazy box after something like that happens to them or around them.

That reminds me.... I really should look into building the mk2 box...

· Super Moderator
4,222 Posts
Discussion Starter · #38 ·
Unfortunately he did learn the hard way.

I will agree that the bottle design is pretty bad. The price of cost savings is evident as all hell on that one.

· Super Moderator
4,222 Posts
Discussion Starter · #40 · (Edited)
Oh? So I got it wrong? Huh... Well lets test something.

70F is 21.1111C(repeating), For proplylene 21.111 is not on there so you have to look at 2 numbers 20 and 22. Which are 132.78 psig and 140.53 psig. So with that said, and I realize that I failed to post the measures in my OP, however, if you take the 133psi I claimed for proplylene. Funny that it coincides with your chart.

So, for 134a, the 100psi I said is for my normal temperature of 90F+ or 32.2C so looking at your chart for that, that would be 103.55. Little off, but not enough for me to say wrong, as 30C is 96.99. Though I should have been clear on that. (Ill fix it in a bit.) Same with propane. So, no I am not wrong, I just failed to list temperatures for the given psi.

Which I have fixed.

· Super Moderator
4,222 Posts
Discussion Starter · #42 ·
Welcome to the internet, where if you disagree with someone and post something constructive, it can be misread as an attack. Poor choices of words on both sides tend to muddy the original intent. Not that I took your post as offense, I may have replied as though I did, but it was not intended that way. (I wanted to get it posted quickly, got interrupted numerous times by dumb things....)

I will clean the OP up once I am home. Did not think about it till you posted. I forgot to fix those.
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