I think the cartridge (well, all the WSM's) was honestly a bit of a passing fad. If I had a rifle chambered in it depending on how much brass you already have I'd just bite the bullet and buy some of the Norma brass. No telling how much longer it'll be around.
I'm in the same boat with my .225 Winchester. Winchester themselves is the only company still making it and only rarely - it sells out fairly quickly. I've only got about 40 pieces of brass for that gun and I'd really like to get at least 100 more.