Anyone know where I could get a stock for FN PBR?

Have you called Mcmillan? Just order direct through them.

Midwest Gun Works use to have spare Mcmillan stocks for FN rifles, super cheap too. You used to be able to get a FN SPR action for around $300 and a Mcmillan stock for it around $300 too.. wish I would have picked a few up.
 
I bought several from Midwest years ago. I wouldn’t want to part with the McMillans but I do have a hogue that I’m not attached to. It’s a standard black hogue without the aluminum bedding block.