KWA strongly recommends using only actual green gas in any KWA product, especially as the use of any other gas, such as propane, red/black gas, CO2, air, or others will immediately void any existing factory warranty.
Standard propane contains the chemical Ethyl Mercaptan (also called Ethanethiol), which acts as an odorant, but will also break down rubber seals and o-rings in a gas gun. Further, propane alone is a very dry gas, and this can damage the many seals in a gas gun and magazine, causing premature wear and functionality issues. When silicon oil is added to compensate, many users will use too much oil, or the incorrect type of oil, both of which can also damage a gas gun by over-saturating the bucking, or by leaving excess oil on the internals of the gun. This can cause jamming, feeding, and cycling issues.