All hitboxes are virutally the same size and position,
relative to the ground position. Think of GunZ as a XYZ-based 3D Object:
http://vignette2.wikia.nocookie.net/...20130906181334
Gunz Hitboxes are literal boxes. Meaning, their position moves with the actor they are associated with. Actions that actors do, for example, lunge, is a static invisible location in which any hitbox that enters will trigger. This is why when you elunge, the lunge action is in a different position than your hitbox. Melee shots do not follow the same logic and are assigned to the hitbox.