CO2 vs Green gas: Which Is Better For Airsoft And Why?


CO2 and green gas are the most common gasses used in airsoft along with simple propane. Knowing that you can choose from each of these gases and knowing that each gas has different properties that will function with a whole range of advantages and disadvantages can seriously impact your airsoft experience.

In this guide, I will share what I know about these gases and what should be your optimal pick in my opinion.

So, let’s see what are the biggest differences between CO2 and green gas and their comparison with other gasses on the market such as propane, red or black gas later in the post.

Advantages of CO2 Disadvantages of CO2 Advantages of green gas Disadvantages of green gas
Works well in a cold environment (below 40 °F or 4°C) Wears internals of a gun slightly more than green gas if used in airsoft guns that are not made specifically for CO2 or lower quality guns
Easy on inner parts, easy to install, use and maintain Losses significant effectiveness in temperatures below 40 °F or 4°C
Higher pressure means more velocity (FPS) and power for running the gun mechanism Harder to install and maintain than green gas Allows adjustment of FPS to pass MED requirements Produces less velocity due to lower pressure levels (bad for Snipers, DMRs, and some rifles)
The major difference between CO2 and green gas

What is CO2 and how it works?

A gas that’s been stored under great pressure usually comes in 12 g capsules  (800psi or 55bar.)

CO2 magazines are created in a way where you insert the capsule in it, which usually means that you empty the capsule before replacing the empty one with a new one. This also means that once you insert the capsule you have to use it preferably in one go.

An opened capsule can not be stored or taken out of the magazine without leaking issues and you can not refill the CO2 capsules in any meaning.

This also leads to issues of not knowing how much CO2 is left in the capsule. This should not be a big deal because you will get used to it and when you notice the capsule is empty, insert the new mag in the middle of the combat.

You will notice the capsule is almost empty with your last 10 shots being weaker and the gun will produce softer noise.

You can find more information regarding the handling of CO2 and answers to important beginner’s questions in my post about CO2 frequently asked questions.

If you are looking to buy CO2 you can find it in local stores, bike stores, airsoft stores, and on Amazon.

What is green gas and how it works?

Green gas is stored under 145 PSI or 10 bar and is the same as propane but with added silicone oil for purposes of better lubrication while it also does not smell as bad as propane. This makes green gas a better option than simple propane and it is a great choice for airsoft guns.

Green gas magazines are designed in a way where you can actually fill them with green gas instead of inserting cartridges in the openings. This means that you can carry a bottle of green gas in your backpack and refill the magazines when needed. However, having multiple magazines on reach while playing is recommended because it is difficult to refill the mag with green gas in the middle of the combat.

Green gas is stored under lower pressure levels than CO2, but there are variants of green gas such as red and black gas that can compensate for lack of power, so for instance the black gas is almost twice as pressured as green gas and red gas is somewhere in-between.

Green gas is less available in stores from what I have seen and heard, but it can still be found in some local stores, airsoft stores, or on Amazon.

What are green gas variations?

  • Propane – A usual gas used in kitchen, fire stoves, for camping etc. Can be used in airsoft, but it is not recommended unless you can keep your airsoft gun always lubricated. This adds up more responsibility and risk while it does not help your budget much (and it also smells terrible!).
  • Red gas – Same as green gas but red gas is stored under higher pressure which results in more velocity and may be a better pick for cold environment (similarly as CO2 works in cold)
  • Black gas – A further improved version of rad gas that is stored under even greater pressure and has enhanced effects

In my opinion, neither red gas nor black gas should be used in airsoft unless you have a specific goal for the benefits they come with. The reason is the higher price of these gases, and proper velocity and cold resistance can be achieved with CO2 and green gas/propane already.

If you are a beginner you should not really bother with Red and black gasses and they might ruin your gun internals.

1. Green gas is more beginner friendly

CO2 is stored at greater pressure and many believe that it should not be kept in the magazine for a long time, while many also believe that leaving green gas won’t do any damage if the gun is stored with it in it.

CO2 requires more maintenance (lubricating) and is harder to deal with if it starts to leak while green gas is simple to install, can be taken off and in whenever you want, and comes with added silicon oil which means you will have less work lubricating your gun. However, you should still not forget to maintain your airsoft gun as indicated in the instructions!

2. CO2 works better in cold environment

CO2 has better cold resistance, so if you will be spending days in the cold environment you should choose CO2 because green gas simply can not keep its properties in a functioning shape in temperatures under 40 °F (4°C).

That said, it does not mean that green gas will completely malfunction under such temperature but it will result diminished in efficiency and even colder temperatures such as anything around 20 °F (-7°C) will make it unusable.

In other words, when you fire your airsoft gun the BB will get projected as far as 30% of its potential.

CO2 in another hand will also get affected by the cold, but it is stored under greater pressure and you will still be able to get a solid efficiency from it even at temperatures below 20 °F (-7°C).

Every gas gets impacted by the cold, but I did not see a great loss in efficiency with CO2, although I presume that there is a minor difference.

I rarely experience cold days where I live, so I do not have to worry about this, but if I played with AEG in the cold environment I would also notice a reduced performance due to poorer efficiency of electricity in the cold environment.

In conclusion, airsoft guns always work better in warmer environments, so it is not only the topic of CO2, green gas, or electricity airsoft guns but also about other components that can be damaged in the cold which airsoft guns are made of (metal, plastic, rubber).

3. CO2 is more powerful than green gas

CO2 helps you achieve higher FPS, but the green gas allows you to adjust the fps based on which green gas you use. However, as I mentioned at the beginning you won’t need to look into red and black gasses but it is good to know they exist.

That said, green gas will result in less FPS but it will be by no means an unplayable FPS and usually this will be a good thing, especially when there are MED requirements in the field.

CO2 will produce better functioning of the parts within the gun, so you can expect that CO2 is better for blowback gas airsoft guns, it may produce a more desired sound when the gun clocks and the added velocity may be a good thing on certain rifles, DMS or snipers for outside plays.

4. There is not big difference in the price

When I took on measuring, I got the following data.

On average, $15 of green gas can result in 1800 shots with a medium FPS non-blowback airsoft gun which means a single shot costs 1.2 cents.

On other hand, 15$ of Co2 can result in 2200 shots with a medium FPS non-blowback airsoft gun which makes the cost per shot more affordable.

However, a similar CO2 FPS airsoft gun with a blowback feature resulted in 1170 shots for the same price.

If I owned a green gas blowback gun I would also calculate how much would the difference of the green gas used be between a non-blowback and a blowback version of a similar airsoft gun. However, I can assume with confidence that a blowback feature would use lots of green gas and you would end up with similar results.

In conclusion, CO2 might be a bit cheaper per shot, but this might depend from market to market because I have seen that the prices vary from store to store.

I have also heard that not every store offers green gas while CO2 cartridges are almost always available on the lager.

Check out your local stores or the place you are buying your airsoft stuff from and make a few calculations for a clear picture.

Can a CO2 airsoft gun use green gas and vice versa?

In theory, you can use green gas in CO2 airsoft guns and vice versa but you should not do it. When you fill a CO2-designed airsoft gun with green gas it may not work as well because the green gas is stored under less pressure than CO2 which will result in a weaker cycle and thus worse performance.

In another case, using CO2 in green gas-designed guns will result in prematurely worn internals due to Co2 pressure levels being up to 5 times higher than green gas pressure levels.

In some instances, there are airsoft guns that can take both without consequences if instructions say so.

You can then use a specifically designed magazine for either CO2 or green gas and continue using your airsoft gun if the magazine fits in.

Once again, READ PRODUCT INSTRUCTIONS CAREFULLY and use the type of gas the gun is made for unless otherwise is indicated.

Are green gas and CO2 poisonous?

Any gas should not be inhaled in large amounts because it can cause headaches and respiratory problems, however, small amounts are fine and won’t hurt you.

Therefore, neither green gas nor CO2 is poisonous but can become dangerous in large amounts.

If the gas leaks it may hurt the skin, so try to avoid gas getting in direct contact with your skin and if it does, clean the skin.

Which gas is better for airsoft? – The conclusion

There is not a simple winner between CO2 and green gas, but I prefer CO2 due to higher pressure levels that are better for the blowback feature, and overall higher FPS helps you achieve better range, pair this with better cold tolerance and you can see why I prefer CO2.

Green gas may be a better option for CQB games where it is important to pass the MED requirements, it is cheaper and easier to use.

In the end, consider these factors but also stick to what your airsoft guns demands, if you have a green gas airsoft gun, use the green gas and vice versa, and if you are yet deciding what gas airsoft gun to buy you can continue to explore this topic in my guide choosing between non-blowback and blowback gas airsoft guns.

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