the ammo used by the military is designed to wound , not necessarily kill rapidly,
http://www.weaponslaw.org/instrument...ue-Declaration
http://www.weaponslaw.org/assets/dow...ng_bullets.pdf
its not designed to expand and maximize internal damage to the full potential available,
as it would be with bullets designed for hunting deer.
I just posted info in a similar 223 related thread
Top shelf ammo for hunting deer with a bolt action .223