That’s changing again - the steel cases all came from Russia and those are now banned from import. The reason steel had taken over the market was because brass and copper were expensive or unavailable in needed quantities. I’m expecting aluminum a la Blazer to make a comeback soon.
Are they actually banning the ammo itself? Or just the weapons? The AK ammo has been stable at about 210$/1000 even after the announcement. And aluminum cases? hmmm. Prolly single-use cases as well.