I think the Senate voting down of proposed gun control legislation has helped a great deal to calm people's fear reaction/instinct. Legislation or proposed legislation will continue, but Presidents really don't want a lot of failed legislation proposals that they really support and push to happen. Looks bad for them; no power or influence. That is probably why the President didn't actively push such gun control legislation early in his first term.
The ammunition shortage started with the re-election of our President in November. At that time, gun sales shot through the roof to record sales highs based on NICS checks performed. It was also the Christmas season buying time.
Then Newtown CT incident happened and the politicans began stomping their feet. NY quickly passed very restrictive gun control legislation. Since then, MD and CO have passed restrictive legislation. You had the ongoing debate in Congress and the media about gun control. The proposed legislation died in the Senate and everyone knew that it was going to be a more difficult road to hoe in the House. Well, those House members didn't get subjected to the intense pressure from the President and their Party when they knew the legislation could influence their future public careers.
It's late May 2013 now and 6 months after the re-election of the President. There is little talk on the News networks about gun control, and inventories are up with black rifles at you local gunshop and prices are down. I would suspect sales of those kinds of weapons are also down relative to Nov > Jan levels.
People who pay attention see inventories of ammunition starting to come back to their local retailers. Prices are coming down, but still elevated over pre-election levels, and inventories will continue to become more robust and suppliers will begin to have popular ammunition in stock for shipment to dealers on request. Things are changing. I expect them to change rapidly in the coming couple of months.
Those that care who would like to maintain a cache of ammunition at home should begin buying on a regular basis in a couple months and start building their cache so that they aren't in the same place as this shortage whether it be firearms or ammunition. Time for some rational buying and planning based on your available resources.