Hey pal
I had the same issue but found an air nozzle here:
https://www.softairgames.net/en/air-nozzles/3850-ergal-air-nozzle-for-scar-h-with-inner-o-ring-fps-fps-spscar-he.html?search_query=Scar&results=389
I've bought this model and it works a treat.