Thanks for the advice. I am using a Dillon 550 and tumbling in corncob with Dillon polishing compound, maybe I am not using enough compound. My tumbler is a Lyman Turbo 2500 with Autoflow as I am a high volume shooter. I will seeif the towel trick works and then see if playing with my media and polishing compound helps. Usually I am running about 1000 cases through the tumbler at a time, and yes, I see the corncob breakdown. I discard my media when it gets a uniform gray and tumbling takes too long to get polish, about 4 - 5 cycles. I also have some walnut media (20 Lbs for $12 when I bought it) but have not started using it yet. Will let you know how it turns out.
heres what was told to me.
Corncob = Polish
Walnut = Clean
ive found that walnut doesnt to a bad job of "polishing" but i use it more for the cleaning. I always keep the older/dirty stuff to clean and remove the dirt/grime from range brass. eventually it will get tossed, but after its almost black in color.
also, if you do add any polish to your media, make sure you run it open top and for at least an hour to dry the polish. I will toss in a couple peices of brass and let them run for 15 minutes and see if any media sticks to the brass.
that could be your problem too, if your polish in the media isnt dry. take a handful of brass after you have polished them. turn the cases over to empty the media and if any is sticking in the case, i would say your media isnt "dry".
one last note, you really shoulnt have to run your brass longer then 1 hour to get them shiny. if you really want the mirror like, it will take longer, but i think its a waste of time/$$$.