The point of hollowpoint ammo is to give off as much energy as possible (ie expand) when it hits the target. effectively that means a lot of tissue damage - much more than when using ammunition with a steel core (FMJ or ball ammo I believe it's american name is). FMJs hardly expand - especially when used against soft targets. Thus, the damage these bullets do is considerably less than HPs.
the point I'm trying to make is that the aim in war is to incapacitate the enemy and *NOT* kill them. the reason for this is to bind resources. all a dead soldier needs is a box and someone to slump him in it. A wounded soldier needs his buddies to carry him off the battlefield, a medevac, a doctor, treatment, rehab, his pay etc etc, all of which cost time, money, manpower and other valuable resources.
viewed from this perspective, it makes little sense to use HP ammo instead of FMJ (on a side note, ballistic armor is a lot more effective against HP ammo than FMJ). Now whether it's allowed under geneva conventions or others and if the americans are party to those, I don't know.
having said that, seeing that the war in iraq and afghanistan are actually insurgencies and any resources bound by incapping insurgents come out of the west's pockets, it might make more sense to kill rather than incap.
also, seeing as incapping is actually a form of weakening the enemy state and bringing about an end to the war, it might miss it's effectiveness against radical fundamentalist muslim insurgents, as it's an ideological war and not a conventional one.
