A Headshot is when a player shoots a player in the head for extra damage. All headshots can only be done on the head obvioud in any condition, as long as the head is hit. As all headshots are icals, a person will sniper. All headshots use the same kill icon.
The following weapons can headshot in one way or another:
Sniper Rifle: Max headshot damage is 450.
Bazaar Bargain: Max headshot damage is 450.
Machina: Max headshot damage is 516.
Hitman's Heatmaker: Max headshot damage is 450.
Huntsman: Max headshot damage 360, is a projectile.
Fortified Compound: Max headshot damage is 360, is a projectile.
Ambassador: No charging or scoping, has a 0.96 delay before headshotting and shots before that will be moderatly innacurate. This can be seen if the crosshair is larger than normal. One headshot damage, 102.
Compression blast: By reflecting arrows from Huntsman/Fortified Compunds, the pyro can score a headshot if aimed correctly.