Airsoft GBB to HPA mod (pro)

A GBB to HPA mod for airsoft rifles. Other tutorials on YouTube just joined a hicap 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 hicap. 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: