As far as the primers go, I have no idea, never used them.

In the 2000-MR, I love the stuff, but like you've seen, I've inly used it in my .308. However, I have had great results with it. Pushing a 175gr Sierra MatchKing around 2700fps, which is humming pretty good. One thing I did notice though using this powder, is it does like to be pushed hot. Like for example, on the Alliant website, the max for a 175gr SMK is 47.7gr. The load that I found that was most accurate in MY rifle was 47.5.

I do plan on using it in my .223, but haven't had a chance to do the workup yet for it between competitions. Just make sure you start low and workup with it, and I think you'll like it. YMMV though.