The title says it all
No, they are not.
Reducing the target's stats, increasing the user's stats, inflicting a status condition (volatile or otherwise) other than bound on the target, and causing the target to flinch are all considered additional effects, so damaging moves that have a chance (up to and including a 100% chance) to cause these effects will have their power increased, in exchange for ignoring whatever chance they had to cause these effects.
As you can see, Priority is not on the list, so Sheer Force do not boost moves with Priority.
Source
Hope I helped :)