A headshot is a direct shot/hit to the head of a target. Scoring a headshot will severly damage your target and most likely result in a instant kill or at least deal massive health loss.
Headshotting zombies
Headshotting zombies is always very effective becuase of the massive knockback it provides, but it shouldn't be the most important task of aiming, because only targetting the head of the zombie(s) will cause many misses at the same time, thus deteriorate the purpose of headshotting. Aiming at the torso of the zombies is the most effective method, and is by far the best strategy to score random headshots for extra knockback.
Tips
- Crouching gives extra accuracy and thus greater chance to score a headshot.
- Never empty your magazine by shooting in one trigger! Spare massive recoil and you will be able to score more headshots!
- Depends on servers:
- If there is no significant difference in knockback, never rely on killing a zombie by either mobbing on him or head-shooting. Even though headshots deal massive damage (over 400 damage with the Magnum Sniper Rifle), it is ineffective because they will catch up with you in time, and there is a great chance they will respawn.
- On servers have high knockback while head-shooting, ignore the previous point.