Stun Damage - Errata
Also please note that stun damage is being errata’d. Weapons do stun damage equal to regular damage (as was the intention all along, but an old version of the table got included in the book). So, you then compare this to the target’s damage threshold, THEN halve it and subtract it from their hit points. Most of the time, stun bolts will drop you down the condition track at mid-levels, and at low levels sometimes it just knocks you out via hit points.
Stun works on low-level characters well, mid-level characters moderately well but still having a solid mechanical effect, and high level characters not so well (because, really, stunning the 20th level Sith Lord is not only anticlimactic but also boring as hell). Against nonheroic, stun is double plus good, especially as you rise in levels, which achieves the stated design goal of the stun rules. It’s not something you should be using against the big bads.