Airsoftology's Q&A Mondays go into the topic HPA tapping, which is basically converting your GBB magazine to use HPA via tethered tank. We see this done by airsoft shooters practicing their accuracy at a range, mostly practial shooters, as it is cheaper than using gas. More topics for this video below:

"Tippmann Mail Call

2:00 - What is Your Favorite Plate Carrier?
5:03 What's your opinion on tri-shot shotguns?
6:58 - Should I HPA tap my GBB Pistol Magazine?

10:32 - Code Red Headsets Video of the Week"