One application I do like FC brass for is heavy bullet 9mm loads. I made a 170gr LFN-style 9mm bullet mold and use it in FC brass. The internal taper in FC 9mm brass is shorter (closer to the case head) allowing heavy bullets to be seated deeper without bulging the case or reducing the bullet base diameter.
Also, the FC 9mm brass seems to hold up to hot loads as well as any other brand I have.
