Those are some good prices . I will be considering getting some of that Fed AR223
I get almost all my bulk ammo here http://www.targetsportsusa.com/
They have free shipping on all bulk ammo . They carry alot of different ammo brands in every cal. They are also out of stock offten on the lower cost ammo but they restock weekly so you have to keep checking back .
I first check prices low to high check out the first few pages then check prices high to low .They will have some other bulk stuff you may not see on the lower price pages .