We’ve replicated a Hi-Capa magazine, and adapted it to take HPA, fed by 30 round shotgun shells.
The adapter comes with a 15cm airline, which can be cut down to your preferred size, and a blackened Foster 22 (US Style) connector fitted.
PLUG AND PLAY - We've injection moulded our own gas router for this adapter, and combined it with our high flow valve and printed feed lips. This means no more donor mags!
You will likely find that sites that do not usually allow HPA adapters in pistols, will have no problem with these adapters, due to their low capacity, and covert profile.