Javaman

One thing to keep in mind about the whole CO2-HPA debate is that the biggest advantage from using HPA is because of the built-in regulator not because of the gas source. HPA's pressure actually varies more then CO2's, going from 4500-0 PSI while CO2 will stay roughly around 850 and might vary +/-500psi depending on the outside temperature and rate of fire(+/-500 assuming normal operation. Leave your tank in the sun or overfill it and you could go up to several Ks). The problem in using CO2 is that most lower-end guns are calibrated to shoot with a roughly 850PSI airsource. As rapid firing occurs the temperature and pressure drops in the CO2 tank which causes a velocity drop off. With a regulator set to output well below 850, say 450psi and the gun tuned to fire at an acceptible velocity at that pressure you will get many of the gains of a HPA setup with few of the minuses of a CO2 one.
1.- Less noise 2.-More shots per fill (Liquid CO2 stores much more gas then HPA per volume) 3.-reliable velocity (no spiking or dropoff assuming no liquid passes the reg) 4.-Cheaper price.

I have yet to see proof that CO2, being considered a dirtier air causes any more damage to the internals then regular friction does apart from Tank O-rings failing after improper removal.

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