So the volcano mystery from anvil of fire has a revelation called pyroclastic shove. Which allows you to bull rush and damage enemies.
It states that you can use it an additional time per day at 12th and 17th level, but I can't seem to find anything about a limit per day. So is this ability useable at will or am I missing something?
It’s definitely not useable at will. If it were, what would be the point of getting additional uses at level 12 and 17? The language of the ability is most similar to revelations that can be used once per day although, you’re correct, it doesn’t actually say that anywhere I can find either.
For a home game, I’d negotiate something reasonable with my DM. For PFS, I’d pick something else to avoid dealing with table variation.
Did you check the FAQ’s? Someone may have gotten this answered already.
It’s definitely not useable at will. If it were, what would be the point of getting additional uses at level 12 and 17? The language of the ability is most similar to revelations that can be used once per day although, you’re correct, it doesn’t actually say that anywhere I can find either.
For a home game, I’d negotiate something reasonable with my DM. For PFS, I’d pick something else to avoid dealing with table variation.
Did you check the FAQ’s? Someone may have gotten this answered already.
There hasn't been any FAQ, because they don't release FAQ's for adventure path books (as far as I know). And I couldn't find anyone else asking the same question.
Oracle Volcano Mystery
** spoiler omitted **
Reading the description it's a standard action, once per day.
One can intuit that if it is usable one additional time per day at higher levels, then it must be usable only once per day at lower levels.
Where does it say it is once per day? Every other revelation that's usable once per day says it is. Erupt from the same mystery, for example, specifically calls out it is once per day.
What the intent of the ability might be doesn't really matter to me, I'm wondering what the default ruling is for how often it can be used in this case.
Comparing it with other Mysteries, it should be quite clear that it is once per day. There is no default rule written, but most Revelations are once per day, 3+CHA per day, lvl*min/day or lvl*hours/day. The rest of the description only fits to once per day, it cannot be something else. Sometimes the rules are badly written, but in this case it is quite possible to reconstruct the actual ruling.
It is the same as in the Cleansing Flames Revelation of the same Mystery. I am playing a character with the Volcano Mystery in PFS, it should not create problems, as long as you use it once per day.