Headshot Mode
From WolfWiki
A headshot mode is included in ETPro, controlled by the bitmask cvar b_headshot:
0 = disabled 1 = only headshots do damage 2 = instagib headshots : hit = kill 4 = only clients can be damaged, not world entities (e.g. barrels) 8 = you can only receive damage from other clients, you can't receive damage from the world, e.g. from an exploding barrel
The instagib damage is controlled by the cvar b_instagibdamage, 400 is the default value.