Thursday, September 4, 2008

Are Airsoft Gas Blowback Guns Earth-Friendly?

Despite their relatively high operational cost compared to Auto Electric Gun-type Airsoft weapons systems, are gas blowback Airsoft-type guns using CFC / Freon-based propellants harmful to our planets still-recovering ozone layer?


By: Vanessa Uy


Even though they can cost several times to run / maintain and on rare occasions repair than your more common battery-operated Auto Electric Gun or AEG-type Airsoft weapons systems, Gas blowback Airsoft-type guns still enjoy widespread popularity. Maybe its due to the fact that when they fire, they resemble uncannily like a real gun firing – i.e. their charging handle and ejection port moves like the real thing every time you pull the trigger. After seeing gas blowback Airsoft versions of the Heckler and Koch MP5 or the M-14 assault rifle in action with the charging handle rocking back and forth rapidly when fired from a full auto mode, it can be quite hard to resist the urge to buy one despite the caveats.

Though still relatively rare in the infantry weapons, sub machinegun side of the replica gun universe, gas blowbacks reign supreme in the handgun / side-arm world of Airsoft gaming. Not only because – at present – only a gas blowback mechanism is capable of mimicking the slide recoil action of semi-automatic pistols, but also because some models sound like a real .22 caliber semi-automatic pistol when they fire. Piston and gear assemblies that power AEG-type Airsoft guns has not yet been made small enough to fit snugly inside replica semi-automatic pistols. Not even for a relatively large handgun like a Colt Series 70. But before we assess the ozone-damaging effects of gas blowback Airsoft-type weapons systems, let us examine first their history.

Back in the 1970’s when the gas blowback Airsoft military simulation game “craze” began in Japan, the gamers use Freon-12 or R-12 CFC-based refrigerant gas. A gas that will be deemed illegal by law in the following years due to it’s ozone-depleting properties. And besides, Freon-12 / R-12 refrigerant gas is a relatively expensive gas just to be vented into the atmosphere just to propel a 6mm plastic BB pellet at more than 300 feet per second. Not to mention that a single molecule of Freon-12 / R-12 or similar CFC-based refrigerants was proven in several scientific studies to destroy 10,000 individual ozone molecules. This spells bad news for the ozone layer.

Contemporary 21st Century gas blowback Airsoft guns utilize a much ozone-friendly (we’re told) gas known commonly on the Airsoft gaming market by its trade name of “green gas”. Green gas – usually sold under pressure in gas cylinders – consists of a mixture of propane, poysiloxane lubricant, and HFC-134a. Green gas is usually used on gas blowback Airsoft guns whose muzzle velocity hovers around 300 to 400 feet per second. When an Airsoft enthusiast upgrades his or her gas blowback weapons system to enable to fire those 6mm plastic BB s faster than 450 feet per second, he or she must switch to a different kind of gas called “red gas”.

Red gas is a trade name of the gas used by Airsoft enthusiast to “power” their gas blowback weapons systems after upgrading the muzzle velocity specs. Red gas consists of a mixture of HCFC-22, carbon dioxide and nitrogen / high-pressure air. Red gas usually reserved to be used only in upgraded Airsoft gas blowback guns because the gas has a relatively high critical pressure, which can cause damage to the slides and bolts of an unmodified gun.

When it comes to the environmental impact of green gas, the refrigerant component of it - HFC-134a – was developed as a less ozone damaging replacement for Freon-12 / R-12. But this resulted in increased electricity consumption in refrigerators / air-conditioning units because HFC-134a is a less efficient / lower specific heat rated refrigerant compared to Freon-12. Fortunately, it takes more carbon dioxide molecules to cause climate change than Freon-12 molecules to destroy the ozone layer so the efficiency issue of HFC-134a can be viewed as an acceptable compromise.

While the refrigerant component of red gas – HCFC-22 – was also developed as a less ozone damaging replacement for Freon-12 / R-12 and is a more efficient refrigerant than HCF-134a. HCFC-22 is somewhat notorious for being a better greenhouse gas compared to carbon dioxide because it has a higher specific heat rating. HCFC-22 use was banned for refrigerant use toward the end of the 1990’s for fears that it might exacerbate the progress of global warming.

Despite the environmental concerns based on the chemical properties of the gases used in Airsoft gas blowback guns, the red gas component HCFC-22 and the green gas component HFC-134a poses only a minimal degree of threat to the ozone layer using data of the studies done in the 1990’s. HCFC-22 and HFC-134a easily degrades compared to the Freon-12 / R-12 that they replaced. And when the newer refrigerants chemically break down in the ozone layer under intense ultraviolet spectrum exposure, they won’t break down as many ozone molecules as they degrade in our planet’s ozone layer compared to Freon-12 / R-12. Also, they are relatively expensive so widespread use is not much of an issue. If this bothers you, there are always those cheaper battery operated AEG guns. Which you can chose to recharge via wind or solar photovoltaic generated electricity.

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