You guys probably already know about this site, but I thought I'd throw this up - I've found some great bulk deals linked through this site (9mm, 45, and 7.62x39) - I like how they have the best user submitted deals in a simple spreadsheet style, with cost per round factored. The .30 Luger section is slim pickings but they are pretty quick to list new deals, I usually check it out a couple times a week.
Gun Deals <LINK