This is an update as I'm finally quite happy with the wood finish
I'll describe the whole process here again briefly.
From the start, the wood was shaped to metal parts by sanding. Unfortunately, getting some metal dust into the wood was unavoidable, but I managed to remove it by brushing with water/IPA (50/50) mixture. The metal dust became very obvious when it turned a very dark blue-black color when water was used to raise the grain before applying finish.
Then the surface was de whiskered and sealed with polyurethane based marine spar varnish thinned with mineral spirits (to consistency of water). This was applied in excess until the wood didn't soak any more, then it was wiped off. When it dried multiple coats of the same varnish were applied (6 or 7 if I remember correctly) to fill the grain. The grain in the front part of the stock filled in 2 coats, in the back it needed lots more.
Once grain was filled I was planning to apply 2-3 extra coats(sanding with 600 grit between coats) of the same varnish and polish to achieve a dull shine look. Unfortunately once I was almost done I managed to cut through my previous layers during sanding. Then once all required layers were done and I was in first stages of final polish (with very fine scotch brite) I managed to not just go through the varnish, but I also pulled it out of the pores in two small spots
I had to spot apply all those grain filling coats again, then I spot applied finish coats there. Finally I added an extra coat all over. This time before the final polish I waited an extra week for the varnish to become harder. The surface was smooth enough so I decided to polish it with very fine scotch brite pad on an orbital sander set to half power. It wasn't easy to polish every little corner without cutting through, but this time I managed it.
So at this stage I'm pretty happy with the finish. It is very smooth to the touch. In person it looks very nice. It has a little shine when viewed at low angle, but looks mat with some depth when viewed head on. Pictures definitely don't do it justice
However I attach some pictures.
The finish could be made better by rubbing with cork backed pumice. If it was a beautifuly figured wood on a double shotgun I would've done it, but for a musket it looks good enough surface quality wise.
I have small gaps between barrel bands and wood. Those will be fixed once I remove excess varnish that collected there. I want to wait at least a month for it to develop full hardness before I start messing with it though so for now those remain.
I also plan to polish metal parts better.
And I still haven't fitted that shim at the back of the barrel. I'll do that as next step.
I also noticed by looking at the photos the inside of my ramrod channel has a full gloss finish
I have to polish it dull with a piece of scoth brite later.
Here are the photos.
