Well, no offense, but that does strike me as slightly crazy. Even if the US government managed to buy up the entire domestic supply of ammo (although without knowing any numbers I do have to raise my eyebrows at that), there's an almost literally infinite supply from outside the US as well. Ammunition is not difficult to produce and there's no lack of manufacturers. If that were a goal of the US government it would be completely idiotic imo. I think it wouldn't be a big exaggeration to say they might as well try to buy all the water in the world.
eta: and if you truely believe that, you've got to fucking put all your money in armament companies, they've got to make a killing
eta2: lol at the tags on this thread.