Now you can have a Gas or HPA Power in the same airsoft gun, thanks to CQB Russian Airsoft. He made an HPA Adapter for airsoft gas magazines which you can quickly install in 20 seconds according to him. All you need to do is remove the gas valve then install the adapter. Attach a hose then hook up the HPA tank and you're good to go. If you want to go back to GBB, just put back the gas valve in again.