Airsoft GBB to HPA mod (pro)

A GBB to HPA mod for airsoft rifles. Other tutorials on YouTube just “joined“ a hi-cap with a gas magazine in a quite rudimentary manner. In this tutorial a far more sophisticated method is demonstrated. The result is a standard looking gas magazine but combined with hi-cap. Same method can be done to green gas magazines as well. If you’re interested in purchasing these magazines, message me through my FB page :) My FB page: Follow me on twitter: