The following is taken from the OFPDR official strategy guide, which I just picked up earlier today.
First the Body HP :
When HP from a particular area of the body drops to 0, catastrophic damage or death takes place. For example, a chest shot with a weapon value with equal to or greater than 8 HP is a one hit kill, while a chest shot with a weapon value with less than 8 HP will just wound.
Here are the Body HP Values :
Head - 4 HP
Chest - 8 HP
Abdomen - 8 HP
Arms - 8 HP
Legs - 8 HP
Now I'll move onto the Wound Effects :
Wound Effects are the side effects of taking damage. Those side effects are as follows :
Light Arm Wound - Minor Aim Loss
Serious Arm Wound - Major Aim Loss
Light Leg Wound - Minor Sprint Loss
Serious Leg Wound - Major Sprint Loss
Next, I'll go over the Weapon Damage Rating :
A Weapon Damage Rating is a rating that gives a value to weapons that indicates how much HP they take off per round.
Here are the Infantry Weapon Damage Ratings. Remember, these values only apply to infantry :
KA-BAR - 12
MEU (SOC) - 5
M16 - 6
M4 - 6
SCAR MK16 - 6
SCAR MK17 - 8
M21 - 12
M82A1 - 16
MP5A4 - 4
M249 SAW - 6
MK48 - 8
There are more values for more weapons but I'm afraid I have to go for now. Later I'll post the rest. Enjoy!