Hey guys, I am looking to buy a gas gun. I am thinking about buying a Glock, WE G18C to be specific (unless you have any other recommendations under $150 for a Glock 18). But anyway, I want to know a little bit about gas guns first. Moslty I want to know just about everything, from what the different gasses are to how long each magazine will go for (bb wise), but I have a couple questions to get started... 1) How much gas does it take to fill up a magazine? 2) How many bb's can get shot out of the fully-gassed up magazine? 3) What is the difference between green gas and propane? 4) And do all gas guns take both propane and green gas? Thanks so much in advance!