Wet tumbling introduced a new problem
I recently switched to the wet/stainless pin cleaning method. The brass is unbelievably clean. I have been using carbide resizing dies for many years without a problem, only recently reloading 9mm.
I noticed a series of about 20 score marks on the last reloads and traced it to the sizing die. Called the mfr. of the die and was advised to clean out brass buildup. Did this with bore solvent, bore brush, and then with 4/0 steel wool.
The problem may be due to having absolutely no organic film on the brass, causing bare metal to metal galling. I then tumbled some of these clean cases in corncob treated with a generous amount of Nu-Finish car polish and it seems to help by putting a slick surface on the outside of the brass.