One of the NRA’s greatest legislative successes, the Firearms Owners’ Protection Act, let dealers sell ammo without recording vital information about the buyers. That law eventually facilitated the online ammo market, which allows sites like CheaperThanDirt to sell 30-round extended clips for $8.99.
The government ought to simply tax the hell out of bullets. Like Chris Rock joked, make bullets $5000 each. And why not? There's no constitutional argument against ammunition, just the "arms."