Saw it on ammo oracle:
http://www.ammo-oracle.com/body.htm#wheremil
Purchase and Storage of .223 and 5.56 Ammunition.
"Q. Where can I get US Military ammo, like M193 and M855?
Due to an Executive Order signed by President Clinton, the US military can no longer "surplus" ammunition, except via the Civilian Marksmanship Program (CMP), and the CMP does not sell 5.56/.223 ammo. US military ammo (most notably from the Lake City Army Ammunition Plant) used to be widely available, but has become quite scarce and the prices quite high, in the last few years. Though some military ammo components are "saved" by contractors disassembling the ammo and selling the components, most expired or out-of-spec lots of ammo are burned. Billions of rounds of ammo, paid for by US tax dollars, are burned yearly."
I thought that this sounded a bit odd, even for the .gov, so I wanted to verify it. So far no dice.
-Owen