generally if the gun operates electronically then you shouldn't use co2 due to the damage it can do to the solenoid. only a few electronic guns can be used with co2 like the GoG eNVy/G-1Is it ok to use co2 gas with the dye proto until I sort out the air system
I know that Proto promoted the SLG as being able to use co2 as a starter gun (even though i'm sure from memory in the manual it says HPA only) but not so sure for the PMR.