We have an HPA tapped HiCapa with M4 adapter at home” : r/airsoft
Primary Airsoft adapter installation tutorial HPA and M4 Glock + Hi capa - YouTube
HPA adapter M4 charger for Hi-Capa series
I know a lot of people hate the Primary Airsoft adapters, but when it's 110° outside, a light kit is a life saver. Also a great first step into HPA : r/airsoft