Guns Hfc Kjw

I'm thinking about getting a gas powered airsoft (KJW Mk1) gun and wanted to use 134a of duster gas instead of propane as a propellant (parents wont' let me use it because its flammable). I was wondering if there is an adapter I have to get be able to fill these gases into my airsoft gun and about how many shots I would be averaging from each one. Also, if the Mk1 shoots .2 bbs at about 400 fps with propane how fast will it shoot them with 134a/duster gas? One more thing, would I be able to use airsplat's bio bbs in this? They're what I use and I've never come across one with any imperfections and they haven't caused a jam yet.

Thanks