Black gas is not Co2, here is a link to a gas comparison chart;
http://www.airsoftcanada.com/showthr...hlight=red+gas
Red gas would not give me a reduction in fps because im not using the Co2 mag (I hate the way it looks) I am only going to be using the green gas mag, so red gas would be great or even black gas, but where to find either is the problem???