I was told Green River did close some time ago. Pity, as it was close by but did have unusal hours. Always was closed when I tried to go there, except once or twice!

I buy my black powder from Graeme Forbes in Melbourne when over there. Can only buy 5 kg in a single day per Vic law. So it has to last in between interstate trips.

As for transporting powders SA reportedly has especially bad laws for transporting any commercial freight of explosives including smokeless powders. At one time was hard to get any propellants. Haven't tried for a long time as I had enough on hand since.