I dont realy remember. To kill someone you need about 2 shoots (pure luck you ca kill him with one and sometimes even 3 but realy rarely) but MG and headshots kill at one shot (if you dont have hlemet but it may kill you in one shoot and may not).
EDIT: I repaste this movie because someone might not seen it and dont check other pages. http://www.youtube.com/watch?v=NVk-vwZlZ-M
EDIT: I repaste this movie because someone might not seen it and dont check other pages. http://www.youtube.com/watch?v=NVk-vwZlZ-M