I just looked back at the core rules for a critical, because I was looking at Auspicious Mark (Barbarian rage power). It looks as if Auspicious Mark can't produce a critical threat when the weapon requires a natural 20. But could it produce a threat if the weapon has an increased threat range? (This boils down, in a sense, to whether there's an implicit "natural" in the increased threat range text "...That is, you can score a crit on a lower [natural] number.")
|
I think you're misunderstanding what Auspicious Mark does (and possibly crits). It lets you add a d6 to your d20 roll. So if you roll a 20 on your attack roll you still crit (and you'd have no need to add a d6 to it). The d20 is the only thing that determines a critical threat. So just like if you roll a 13 and have a +7 for a total of 20 doesn't mean a crit, any other result plus a d6 isn't a critical threat unless the d20 actually has a critical threat on it.
All Auspicious Mark does is add an extra d6 to beat the opponents armor class (or other checks to beat the DC).