the pistols in arma3 are pretty much useless because of the lack of ability to kill or injure another player/AI.
I did a small test and placed some Opfor in the editor and shot them with the pistol at different ranges (5m, 10m, 25m, 50m). I can understand if at 25 or 50 meters the bullet will have little chance to kill or even injure the enemy but i was shocked to see that it still took 3-5 shots to kill the man at 5 meters (This test was to shoot at the body not at the head). after considering that they were wearing some form of armor i did the same test on a civilian and got the exact same results.
i am aware that head shots will most likely kill then enemy but it is not a reliable place the aim for especially at a distance.