Lots of reading to do regarding ammo, but all of it very useful:
http://www.ar15.com/ammo/project/Sel..._FAQ/index.htm
http://www.ar15.com/ammo/project/Exo..._FAQ/index.htm
Now I'm not saying that it doesn't do what they claim, but I would like to see more testing done. Till then I'll stick to HST, Ranger and GoldDot.