When I did my HW77 stock, I used fine sand paper, 00, 000 and 0000 grade wire wool, to remove the stain and smooth the stock.. Just be careful around he butt pad area, and maybe mask of the chequering, does not really matter about the stain there, as its dark anyway.
On the stock subject, I recently carved out a lovley place for the palm of my hand to go on that stock, with helps me grip it better.
It took 1 hour, 1 black and decker cordless drill, a round sanding pad for said drill and a little effort for a really professional job (IMO anyway).
I would post some pictures but my digicamera is really crappy.
Pete