I'm just getting into reloading for .45 ACP and I have a Dillon tumbler (the smaller one). I've been told that I can get corn cob media from Wal-Mart so I picked up an 8 pound bag from their pet department. However, the media isn't as fine as some of the name-brand stuff like the colored stuff from Lyman's. Is the Wal-Mart stuff going to be sufficient or do I need media where each bit is like Grape Nuts?