We just started playing Rogue Trader and the Missionary player asked me how Quality affects Flame weapons, since you don't roll to hit. Anyone has an idea how it works?

Largely irrelevant for Flame weapons, as the bonuses to hit and extra damage are only applied to melee weapons. Craftsmanship affects the chance to jam (roll a d10, only jams on a 10/Never jams from a roll. GM fiat on whether psychic phenomena can still cause a jam). Not sure how you'd handle a Poor-quality flamer, though.

I'm that player, and I've checked that they actually do something, because Flame weapons jam on a roll of 9. The Reliable quality for Good-quality flamers would kick in then, and the jam wouldn't happen with a Best-quality flamer.

HDaniel said:

Yeah, that's it.