Midway has brass. Try this link....

http://www.midwayusa.com/ebrowse.exe/browse?TabID=2&CategoryID=7401&CategoryString=9315+***+652+***+670+***+9013+***

For bullets, try Woodleighs, and Midway has those too.

As an alternative, you might try using Remington Ultra Magnum brass. Although the rim is slightly rebated, I have been told by 404 Jeffery owners that this brass works just fine. I don't own a 404 Jeffery, so this is really third hand info. But, Remington brass is good quality and it is relatively cheap.

RobertD