From this article, it appears that a person can be in violation of some law (fed or state??) for having too much ammo. What are the limits on ammo ownership? I had never before heard of this.
http://news.yahoo.com/mexican-couple-admit-27-000-round-ammo-cache-235730092.html
http://news.yahoo.com/mexican-couple-admit-27-000-round-ammo-cache-235730092.html