http://www.thegunzone.com/11april86b.html
QUOTE
An adversary gets hit square in the head with a 158-grain +P, and he isn't stopped, you are having a bad day! McNeill, Mireles and Hanlon had bad days… only Grogan and Dove had worse ones. In light of this information, perhaps John Hall's "ammo failure" assessment has some merit… but then as a war veteran chum with more than three dozen confirmed kills continually asserts, "the more I see of this stuff, the more I'm convinced that nothing hand-held is absolutely reliable."
I think that hitpoints or damage boxes is probably "wrong" compared to a system in which each time you were hit by incoming fire, there would be a random chance that it would kill you or incapacitate you in some way, and that these probabilities would increase with each consecutive hit on you, but that otherwise they'd have no immediate drastic impact.
(You'd still bleed to death after a number of minutes.)
There would be more record keeping than in most current RPG systems as I imagine you'd need a "physical debilitation" track as well as a "systemic shock and trauma" track, but all in all it would allow for more realistic firefights and more realistic first aid, too. Maybe more detailed first aid skills. According to something someone posted a long time ago on the Bear's Pit, the first aid they teach you in the military for gunshot wounds is a bit different than normal civilian first aid where all you do is press down and stop the bleeding.
(Why do they keep all the cool stuff from normal civilians like me? What if I want to know how to perform first aid for a gunshot wound? What if I want to know how to apply a tourniquet and stabilize someone in an emergency?)