CO2 is in a liquid state when "stored" in the cylinders. This is the same with paintball tanks, they have liquid CO2, which is ABOUT 1800 psi in the tanks when full. It was stated that in the winter temps the preasure goes UP in the tank, this is not true. It is actually lower. Leaving the windows of a car up, place a CO2 tank inside the car in the middle of the winter. Now do the same in the middle of the summer and it is almost a sure bet the burst disc ( safety disc for to high of preasure ) will blow releasing the tank preasure BEFORE the tank explodes.

When CO2 is released from the "tank", the preasure at which it is stored changes, causing it to become a gas state. While doing this, it release energy in the form of heat, becomin very cold. ( I can't remember the terms for this, but it is exo(something) and endo(something) (if I remember that part right anyway! It is a few years since I had a chemistry class. Maybe one of the "students" can help me!!!!)

As stated, for the same size "tanks", you will have a higher psi in a tube from liquid CO2 "tank" than compressed air (or nitrogen) as even under preasure, compressed air is still AIR.

I was actually checking pumps out today, and I still don't see the benifit of CO2. It may be smaller, and lighter, but you have to replace them every so often. I look at it the same way as my yard waste. I bought some 40g garbage cans ONCE. More money up front, but I still have them after 4 years . Now, where did those $2.00 "yard waste bags" go I put at the curb! (Please understand this comparison in the fact I have a HUGE Maple tree in my front yard. 3 pkg's of bags wouldn't even be enough every fall! )

Chris