First take off the upper reciever, bolt, and bolt link if you havn't already. The ram(air cylinder) is held in by one allen screw that's just above the front grip frame screw. They can be real hard to pull out, I use a wrench on the end of the ram to twist while pulling, but if you twist too hard you can damage the ram. If it's really stuck in there pull out the valve, one set screw holding that in from the bottom near the back grip frame screw. With the valve out you can tap out the ram, hammer, and carrier with a wooden dowel.