Maybe I am naive, but all this blowing up about DHS ordering bullets, parts etc is much to do about nothing.
DHS gets tons of funding right now, no one wants to cut their budget and be blamed for hurting the security of the nation. When a federal agency has lots of funding they spend it, if they do not spend it they do not get it back the next year. One of the better ways to ensure the money will be in the budget is to sign a contract like this which makes it more difficult for them to lose the money when cuts come.
The other part, IMO, is as I said, they have the money. When you give a giant government agency money they will find all kinds of creative ways to spend it. Most of them being things they don't "need".