Bought some really dirty 40 S&W brass. Got the bright idea to briefly wet tumble it with the primers still in so it was clean(ish) before I decapped and resized.
I know now that was a mistake, and the source of my problem.
Took me a while to figure it out, but what's happening is about 1 in every 7-10 pieces of brass gets "hung up" when I'm decapping/resizing. By that I mean the primer isn't fully exiting the case. The interesting thing is, it certainly IS exiting the case, but the anvil is getting stuck on the decapping pin and the primer is being partially reseated as the pin withdraws from the case. A second round through the die clears it.
Corrosion of the primer to the case from the wet tumbling is the source. Lesson learned, and easily preventable in the future.
What I should do is dump this brass in a box, squirrel it away, and try to forget about it. I already have 12,000 or so pieces of fully processed 40 S&W brass. Just not sure if my OCD is gonna let me walk away from it.
Any ideas?