In the world of air pistols the most common method of pushing BBs or pellets out of the barrel is via compressed gas. After all these are airguns we are talking about. When it comes to repeating and blowback air pistols there are two major propellants that shooters will encounter: 12 gram CO2 and green gas. For those of you who have only shot .177 caliber pistols, you are most likely familiar with those small capsules of fun. But what is green gas? Stay tuned and we’ll flesh out some facts about each and how you can best use the appropriate platforms.
Carbon Dioxide Air Gun Capsules
CO2 powers nearly all BB pistols and a good deal of 6mm airsoft pistols. 12g CO2 cartridges are easy to find. Nearly any department store and just about all outdoors centric stores, like your local airsoft dealers, are going to have at least one brand of CO2 on the shelf. Airguns have used CO2 as a propellant for scores of years at this point. Reasons are many, but suffice to say that CO2 is cheap, reliable and has just one major achilles heel. That disadvantage would be temperature sensitivity. Once the mercury dips below the 60 degree mark, the valve on a CO2 powered air gun can freeze up after a succession of shots. If you take your time you can prevent or at least delay this from happening, but when it gets cold enough things just grind to a halt pretty quick.
Depending on the quantity the 12 gram CO2 cartridges are purchased in, the cost per unit usually ranges from $.50 to $.90. In .177 most pistols will get between 70 and 90 shots per cartridge. This works out to a cost per shot of about $.01 and $.02. Depending on the model of CO2 powered gun you are using, the CO2 cartridge may be housed in either a drop free magazine or it could be located in the pistol’s grip. 12 gram CO2 can be found powering standard air pistols as well as airguns that shoot plastic 6mm airsoft BBs.
Green Gas for Airsoft Guns
Green gas pistols are ran by a propellant mixture of propane and silicone oil, like Elite Force Fuel. But unlike CO2, green gas is only used to power 6mm airsoft pistols. Since airsoft BBs are much lighter than steel BBs, not much power is needed to launch them at a sufficient velocity to get the job done. Additionally, since the sport of airsoft involves shooting the 6mm BBs at other players with proper eye pro and face protection, velocity is regulated at most airsoft fields. Generally that threshold is around 350 FPS, a speed that allows airsoft guns to be accurate and have range, but not so fast that players have an elevated risk of injury.*
Airsoft play takes place in all sorts of weather conditions. It’s not uncommon to see players engaged in a match in blowing desert dust, rain, or extreme humidity. The addition of silicone oil to the propellant helps keep the gun running reliably during use. It is also very fast and easy to recharge the gas reservoir on GBB (green gas blowback) air pistols. However, GBB handguns tend to get only 30-40 shots per fill. This is not really viewed as a disadvantage when it comes to airsoft milsim--realism in shot count and magazine capacity is preferred in this field of use because as we all know that in real life magazines run empty from time to time.
The good news for a shooter adopting a GBB style pistol is that a single can of Elite Force FUEL will power a pistol for about 1800 shots. With a cost of about $15 per can, training and practicing with green gas airsoft guns is very economical, running just barely above one cent per shot. On the downside, green gas is not as readily available as CO2. Unless there is an airsoft specialty store close to you, chances are you won’t be able to find this airsoft fuel at your local sporting goods store.
Should I Choose CO2 or Green Gas?
If you are looking for performance, CO2 may be your best bet. CO2 is a higher-pressure gas and depending on the make of the pistol can provide a harder recoil on blowback airsoft pistols. And CO2 performs better in colder weather, although it is temperature dependent as well.
For supplementing firearms training you may be better served by a GBB style airsoft gun. 6mm airsoft BBs will still ricochet, but not nearly as bad as steel BBs should they hit a hard surface. However, like CO2, green gas is temperature sensitive, but the airsoft GBB option can be easily utilized in a heated garage during the winter months-- that is if you can move the cars out for a spell!