Here's a brief interview with Prof. John Lott:
http://www.press.uchicago.edu/Misc/Chicago/493636.html
Other than teflon rounds, which can defeat vests, I don't see why the fact that an military force uses the ammo should make it inappropriate for civilians?
Besides the question about tracers posted by hrdwareguy, what's wrong with caseless ammo?
Teflon is bad for cops wearing vests so I'll grant you that, but what's up with the others? Or is it just that you figure that it's bad because it's military? The real question to be answered would be why should it not be available?