HI Dona>I have had my pistol dies scratch the cases,I changed to carbide dies and haven't had that problem since.
As far as using cases picked up causing that problem it can hapen with your cases when you pick them out of the dirt or they drop on the floor with lube on them.I throw them in the case cleaner before I load and still have a scratch .I found it's not the die that is damaged( it could happen) it is a little grig that is stuck on the sidewall of the die and brass is smeared to the die wall holding it in place.I remove it with a little comet on a rag with oil raped arround a wooden dowel and spin it with a drill and clean it out.Just dont get to carried away.The die is very hard it takes a lot to grind down the die body.If the die body is scrathed,than I guess you replace it or put up with it.Lp.
