Re: a little question
If you are getting HPA there is really no use for an expansion chamber. What the expansion chamber does is allows co2 to expand. If you are getting a HPA tank get a Regulator, this will allow you to control the operating pressure of your gun. Some good regulators: CP Regs, Bob Long Torpedo Regs and Palmer Stabilizers. There are more but those are some of the best regs around and are easy to find.