If it were me (and it has been although it was way less than a couple 100 rounds) I'd pull them all and dump the powder. You're going to have to pull your expander ball out of your size die to re-bell the case mouth before you can re-seat the bullet anyway. Weighing the rounds will certainly tell you how much they weigh, but as you probably know and has been said bullets can vary as much as 3 gr and so can different cases. A double load of Unique-like stuff can make a mess. I use the plier method described above. Sometimes I get away with minimal marring of the bullet, other times it has to go back in the pot. Really nothing else to do. Aggravating? Yes. Damn good thing you caught it.
Alan
