How often do you clean your dies? I have some Redding dies that seem to require frequent cleaning to prevent the build of brass on the inside--like every 100 round or so. That seems excessive to me but is the only way I can prevent scratched cases. Solvent doesn't get the brass out, so I use Flitz compound on a patch that I drape over a bore mop that I've put into a power drill to buff out the built up brass. Seems to work, but the dies still gaul up pretty fast again.