Greetings, citizen.
I bought this one to try, but GBB isn't my thing, even on HPA.
This one was used by the previous owner; I haven't used it myself in a full skirmish yet.
It has a new NPAS in it; I bought this at Proactstore.
(NPAS Loading Nozzle Group for APFG MCX、Marksman K1A、Maruyama ISO556 GBB (Original Parts)
It is now set to 0.8J with the original MAG. (green gas)
On HPA it shot a bit harder. If you want to shoot it at 1.2, you need to turn the NPas open a bit (I can show you).
WARNING! Comes without silencer and GRIP.