How bad is propane for an airsoft pistol?

Green Gas is propane, the only four differences are the scent additive (propane itself is a colorless oderless gas; as sold to consumers, propanes scent additive smells like rotten eggs, Green Gas has a less annoying smell but the smell is not a big deal) Green Gas also contains silicone oil in it to keep the mag and internals lubed and properly functioning. Propane does not have the oil, HOWEVER any good airsoft store should be able to get you a bottle of light silicone oil to put a few drops in the propane adaptor before filling the magazine and that will not be a problem. Propane is sold in 1lb tanks (camping tanks) that are steel and were designed for the pressure exerted on them by the gas, whereas green gas is sold in an aerosol can that is not strong enough to prevent the possibility of the can rupturing due to gas pressure.