You realise that past level 3 armour pistol bullets to the vest do basically nothing. The vests are for 6.5 rounds, i mean even 5.56 are pretty shit against carrier rigs etc. Aim for the head!
@Izaya get yourself a Rook 9mm with a 30rnd mag, it's like the Arma equivalent of a TEC-9 in CS:GO. Look at the general direction and smash Mouse 1 as rapidly as possible.