I have used alkanet root and turpentine. I allow the alkanet to soak for about a week or two an then evenly paint the stock with the stained turpentine. I may go over that several times to get the right color.
I then lightly apply several coats of alkanet root stained boiled linseed oil. The last two coats have a few drops of true oil mixed in as that actually sets up. A gunsmith I know adds a small amount of Japanese drier to his alkanet/linseed oil.