Data coming from Afghanistan and Somalia have indicated multiple shots have been required to effectively stop targets. That I have heard from multiple sources, but I cannot say what exactly that means. Were the targets beyond resonable fragmentation range of theh 5.56mm? Did it take multiple shots to kill the target, or to stop him from any further aggression? I hope we can get some first hand data. I do know M60 gunners from Vietnam who said that targets hit with 7.62mm from about any resonable distance went down and did not resume aggression. But these were firefights and it was from a fully auto weapon, so there may have been fear or multiple hits involved.
On a side note, SOF mentioned in an article that in some war-torn African nations, the #1 most common injury in the Hospital waiting room is someone sitting around with a 9mm bullet in him - sometimes several. Why? Because they aren't dead.
If you ask the question of yourself, what would you do? If I took a round in a limb, I might keep going - depends on how desperate the situation is. If I took either round in the vitals, I am going straight to the medic - or having the medic come straight to me, most likely. Now, if I am a religious fanatic, doped on quat, and I believe I will enter paradise if I can just kill one infidel, I may expend my last few breaths and pints of blood trying to take an enemy with me. This is such a hard question to assign a straightforward answer to.
SIEGE