It won't end until the threat of gun/ammo bans are gone. Once there is a final vote on the various federal level proposals then the panic buying will ease off. There still may be localized panics depending on each state and the local laws (like Illinois), but it will die down, once everyone thinks they have "enough".
Just reading through other threads and other fora, most people don't believe they have "enough" at the moment and are looking to either buy more when it becomes available or start reloading. So I predict a continued run on both factory ammo and supplies for at least another 9 months.
If I was going to start a business, it would be ammo manufacturing. I don't see it ever getting back to "normal" again and here's why.
1. The surplus from the end of the cold war is gone. The salad days of the mid '90's when the former Warsaw Pact opened their warehouses and started shipping everything they could turn into hard currency is done. That cupboard is bare, and won't happen again in our lifetime.
2. Same with US/NATO/South Africa, etc. It was called "Surplus" for a reason. There is no "Surplus" of anything anymore. (ammo, guns,or mags).
3. Ammo manufacturers don't seem to be adding capacity. The war in Iraq is over, Afghanistan will be winding down, the military os getting smaller and raw materials (lead and brass) are getting more expensive (transport costs seem to be the driver.) State Taxes and labor costs are what drove Olin (Winchester Ammunition) from East Alton, IL to Oxford, MS. Gov. Quinn and Mayor Emanuel should be thrilled.
4. I only see the need for ammo increasing. With that many more firearms sold, they'll get used.