Green Gas vs CO2: Airsoft Gas Explained
Both power gas blowback airsoft guns. They are not interchangeable, so the right choice starts with what your magazine is built for.
How green gas and CO2 work
Green gas is a pressurized airsoft gas, usually blended with silicone oil to lubricate seals. You fill the magazine from a can. CO2 comes in sealed 12 g cartridges that load into a CO2-specific magazine.
| Green gas | CO2 | |
|---|---|---|
| How you fill | Fill the magazine from a can | Insert a 12 g cartridge into a CO2 magazine |
| Pressure | Lower | Higher |
| Cold weather | Pressure drops noticeably as temperature falls | Holds pressure better in the cold |
| Recoil and FPS | Softer | Stronger kick and usually higher FPS |
| Wear on parts | Gentler | More stress on parts not built for it |
| Compatibility | Standard gas magazines | Only guns and magazines designed for CO2 |
Which should you use?
- Most GBB rifles and pistols: green gas, filled from a can like KWA Green Gas.
- CO2-ready guns: the KWA NS3 system in the ATP-GT is built for CO2 while staying compatible with green gas. Use the dedicated ATP-GT CO2 magazine for CO2.
- Not sure? Check the manual in our Manuals & Diagrams library before putting CO2 in any gun.
How to fill a green gas magazine
Hold the magazine upside down (floor plate up) and the can upside down and vertical, with the fill needle pointing down into the valve. Fill for about 30 to 40 seconds and listen for a faint hiss. Prime new magazines before the first fill to reduce air pockets, and keep magazines out of direct sunlight.
How to prime a gas magazine (KWA Insider on YouTube)
Frequently Asked Questions
Can I put CO2 in a green gas magazine?
No. CO2 runs at higher pressure and needs a magazine built for it. Use CO2 only where the manufacturer says it is supported.
Is CO2 better than green gas in cold weather?
Generally yes. CO2 holds pressure better as the temperature drops, while green gas loses pressure in the cold.
How long do I fill a green gas magazine?
About 30 to 40 seconds with the magazine and can both upside down. Listen for a faint hiss while it fills.
How many shots do I get from a can of green gas?
It depends on the gun, the magazine and the temperature, so there is no single number. Bring a spare can on game day.