[Smokey Joe]

TimB--Welcome to The Magnificent Obsession (I refer to reloading of course)!

Re tumblers--IMX there's not a nickel's worth of difference among 'em--get the cheapest one you can find. The biggest one you can find is probably too big for your use unless you are processing hundreds of .38 cases at once. It'll just require the use of a larger batch of corncob.

/Rant mode:ON/ Re "media"--BTW, that's plural: You use a polishing MEDUIM to clean your brass. A medium is a thing that does a particular job. It's Latin, so the plural is MEDIA. You hear of the broadcast media (radio and TV; therefore a correctly used plural). If you buy a sack of corncob and another sack of walnut, you bought media (2 different things to do the job of polishing/cleaning brass.) But if you only buy the corncob, you bought a sack of one medium. /Rant mode:OFF/

Re pet store walnut and corncob--they are cheaper by far, and have been reported to work just as well. When I use up my current supply of "official" tumbling media, that will be from where my new stuff comes.

I have tried a treated medium exactly once. The brass was beautifully shiny, but it had a sort of coating on it, inside and out, that I didn't like. I have gone back to using plain ground corncob medium. My brass isn't as shiny, but OTOH there is no substance adhering to it that might affect the powder burn on the inside, or the chambering on the outside of the brass. Others use treated medium and they like the result. YMMV.

I use a sifter very similar to Kayser's, and it works fine for me. Dillon and Midway both sell fancy sifters if you want to spend the $$.

Enjoy reloading!