I agree on the fffg granulation. Black Mag'3 which is now my powder of choice is very fine and at least fffg grain size. I find BM3 burns a little cleaner and with a little more power than APP. They are apparently similar formula or type powders. I believe they are both ascorbic acid based and as such the corrosion on steel is not a problem like the other synthetic powders. I think BM3 is a little more moisture resistant than APP based on what data I can find.