If you have almost no ammunition on hand, go get more. If you already have a few hundred rounds, consider passing up the next box in favor of helping Heller 2 case. Its success would do much to reduce the need for that ammo stash. Think of it as the strategic move to complement existing tactical preparations. Of the legal advances for gun rights, Heller seems to me the best bang for the buck. I already give money and time to it.
If you can help, please do. A box of ammo's worth isn't much but it buys badly needed legal might. And if short on cash, please re-post this appeal for others to see.