One of the biggest debates in the airsoft community revolves around the choice between green gas and CO2 as propellants for airsoft guns. Both options come with their own set of advantages and disadvantages, making the decision a matter of personal preference and playing conditions.
Whether you’re a beginner or an experienced airsoft player, understanding the differences between green gas and CO2 can help you make an informed decision. In this comprehensive guide, we’ll break down how each propellant works, compare their pros and cons, and help you determine which is the best choice for your airsoft needs.
What is Green Gas?
Green gas is essentially propane with a small amount of silicone oil added to it. The silicone oil serves as a lubricant that helps protect the internal components of airsoft guns, ensuring smooth operation and longevity.
Green gas is stored under pressure inside an airsoft gun’s magazine in liquid form. When the trigger is pulled, a small amount of green gas is released and expands into a gaseous state, creating pressure that propels the BB forward. Unlike propane used for cooking, green gas is treated with additives to minimize odor and improve safety.
Advantages of Green Gas
✔ Easier to use – Green gas is stored directly in the gun’s magazine, eliminating the need for external cartridges.
✔ Less expensive in the long run – Green gas is more cost-effective compared to CO2 cartridges.
✔ Less wear and tear – The lower pressure of green gas results in less stress on airsoft gun components.
✔ Quieter operation – Green gas guns tend to be quieter than their CO2 counterparts.
Disadvantages of Green Gas
✘ Lower muzzle velocity – Green gas provides less pressure than CO2, resulting in lower FPS (feet per second).
✘ Not ideal for cold weather – Green gas is sensitive to temperature changes and performs poorly in cold environments.
✘ Bulkier to carry – Green gas canisters are larger than CO2 cartridges, making them less convenient for refills during games.
Green Gas in Japan
In Japan, green gas, commonly used in airsoft guns, is restricted due to its high pressure, flammability and potential for injury or damage. The Japanese government classifies it as a hazardous material, and its use is tightly controlled under safety regulations and requires a licence to use. Interestingly, what’s sold as “green gas” in Japan is typically CO2, stored in external canisters. This mislabeling leads to confusion, as CO2 generates higher power output than the regular green gas (propane), which is why its use is more regulated.
What is Co2?
CO2 (carbon dioxide) is another popular airsoft propellant, typically stored in small, pre-filled cartridges called CO2 bulbs or capsules. These cartridges are usually inserted into the grip or stock of an airsoft gun.
When the trigger is pulled, a small puncture is made in the CO2 cartridge, allowing pressurized gas to escape and propel the BB forward. Because CO2 operates at a higher pressure than green gas, it results in increased power and faster muzzle velocities.
Advantages of CO2
✔ Higher FPS – CO2 guns typically shoot at higher speeds, making them more powerful than green gas guns.
✔ Better cold-weather performance – CO2 is less affected by temperature fluctuations and performs well in cold conditions.
✔ More realistic blowback – CO2-powered blowback pistols produce stronger recoil for a more realistic shooting experience.
Disadvantages of CO2
✘ More expensive to operate – CO2 cartridges are single-use and can become costly over time.
✘ Harsher on gun components – The higher pressure of CO2 causes increased wear and tear on internal parts.
✘ Inability to “top off” cartridges – Once a CO2 cartridge is punctured, it must be fully used before replacement.
What Makes Green Gas and Co2 Different?
Green Gas vs CO2: Side-by-Side Comparison
| Feature | Green Gas | CO2 |
|---|---|---|
| Cost per use | More affordable | More expensive |
| Muzzle velocity (FPS) | Lower | Higher |
| Cold weather performance | Poor | Excellent |
| Blowback realism | Softer | Stronger |
| Ease of use | Easier to refill | Requires cartridge replacement |
| Wear on gun | Less wear | More wear |
| Noise level | Quieter | Louder |
The main difference between CO2 and green gas airsoft guns lies in the characteristics of their propellants. CO2 airsoft guns offer higher pressure, resulting in faster muzzle velocities. Other benefits of CO2 include better performance in colder temperatures, more noticeable recoil for a realistic feel, and a more consistent power curve over multiple magazines. CO2 is also more widely available than green gas, as green gas is classified as a “dangerous goods” and can’t be shipped by air. In Japan, green gas is illegal, and airsoft guns typically use HFC134a, a less flammable but weaker alternative. Outside Japan, HFC134a is rare, though Europe offers a non-CFC version called 144a.
Green gas, on the other hand, is cheaper and easier to top off. You can add more gas to the gun from a canister, while CO2 requires replacing the tank.
However, each propellant has drawbacks. CO2 is more expensive, and once a CO2 bulb is pierced, you must either use up the remaining gas or waste it. CO2 bulbs also can’t be stored in the gun for long, which can lead to further waste.
Green gas has its own downsides, such as bulkier canisters that are harder to carry, lower muzzle velocity, and the fact that green gas guns cool down faster, requiring more frequent refills.
Can I Use Green Gas in a Co2 Gun?
Some airsoft guns are designed to use both green gas and CO2 magazines. However, unless your gun is specifically built for both, a green gas gun won’t function properly with CO2, and most CO2 guns won’t work well with green gas. It’s also important to note that the use of green gas is illegal in Japan.
Is Green Gas Dangerous?
Under normal conditions, green gas is safe. It is non-toxic unless inhaled in excessive amounts. The main danger lies in its flammability. As long as it is kept away from open flames, there is no risk of green gas igniting on its own.
Are There Other Kinds of Airsoft Propellants?
Besides green gas and CO2, other common airsoft propellants include HFC134a and high-pressure air (HPA). HFC134a is a weaker variant of green gas, suitable only for plastic airsoft guns that require lower pressure. However, since it is a Freon-based gas and a CFC, it is banned in most countries due to its harmful effects on the ozone layer. In Europe, a non-CFC replacement known as 144a is available.
HPA airsoft guns use compressed air, similar to modern paintball markers. They can be refilled at home with an air compressor and the proper adapter or at airsoft and scuba shops.
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