For what it's worth, I am willing to bet you got ahold of some old Federal brass which was defective. Since I am new on the Site, apparently I am unable to post links but if you do a search for "The Gun Zone .40 S&W Kaboom" you will find the info including lot numbers of the defective ammo. How do I know? Been there, done that, TWICE. Apparently I am not able to post pic's either yet. (I tried to attach a pic of my misfortune)
Bottom line guys and gals - DO NOT SHOOT OR RELOAD ANY .40 S&W FEDERAL BRASS WITH THE FC HEADSTAMP (this came from the manufacturer's rep)
BTW - Federal is replacing the 4 boxes of ammo that I had with new.