I have bought over 6000 rounds in the last 7 weeks at various Wal-Mart stores in my area. That includes CCI AR Tactical bricks, Winchester bulk bricks, and Federal Bulk and auto match bricks. Every time I found ammo, it has been before 9AM. From what I understand, the truck comes at night (after 10PM when the gun counter closes) and the 7AM counter person (usually the dept manager) stocks the ammo.

Lucky for me I go to work at 7AM, so I have been stopping in to check stock on my way to work and have had success. The website used to help, but now they pulled ammo off the site period.