I know that this is a really late posting but here goes...

I bought a boyds gray laminate and after fitting it to the barrelled action, I spent hours (literally) sanding it by hand or with a sanding block until it was smooth as glass. I ended up with several blisters out of the deal and one beautiful stock. The last grit on the sand paper was 500 or 640. I then applied linseed oil and rubbed it out after each coat had a chance to get tacky. I did 10 coats. More blisters again. Finally, I wanted to ensure that it wouldn't draw moisture so I tried to seal it with a matte finish polyurethane. Big mistake, huge mistake! The poly urethane wanted to bead up on the surface and gave a very uneven coating.

Guess what, yep, more blisters... I sanded it down and applied a few more layers of linseed oil and called it good.