[Styrak]

I assume duster would not have enough "oomph" to run the WE system. It's made for propane and CO2.

The reason why it would vent after a few shots is that it doesn't have enough pressure to blow back the bolt/nozzle assembly all the way and therefore the gas valve on the mag stays open and vents the gas.

Use it what it was intended for, use propane or CO2.