Originally Posted by
dsbrantjr
CO2 cartridges are filled to about 900 psi.
CO2 cartridges contain liquid CO2 and are filled by weight, not pressure. Liquid CO2 will always stabilize around 900PSI (Depending greatly on temperature) no matter how full it is, until it's nearly empty.
Same reason they fill propane tanks on a scale instead of using a regulator - some gasses don't work that way.