Reloading

Welp, my .375 Winchester fire has had a little water thrown on it. I was reloading the new Fury bullets that arrived and the neck tension from the 30-30 converted brass from Brownell's seems very lacking. I also tried with the same Speer 235's that worked previously and same issue. I have Lee dies and I have the FCD, neither can crimp enough to stay put. Most can be pulled out by hand, all can be twisted in the case. I have only ever had this problem one other time in my over 35 years of reloading and the FCD was the fix. Research says the brass neck may need annealing to soften to be able to grip without spring back. Any advice appreciated.