Hi Lone Wolf,
An English fowler would most likely be stocked in English walnut. To be clear, English walnut is
Juglans regia and is the same species as European, French, Turkish, Circassian, Armenian, and Italian walnuts. I suspect your stock is American black walnut (
Juglans nigra), which is a different species. Black walnut tends to have cold purple-brownish tones and I prefer not to darken it but warm it up to look more like English walnut. Here are some examples of black walnut stained to look more like English walnut.
The trick is simple, just paint the black walnut with a yellow dye. That wipes out the cold color and warms it up a lot. I use yellow aniline dye dissolved in water and I start painting the stock with the water-based color as part of the whiskering process. It helps show up scratches and rough spots and I scrape or sand it off completely each cycle of whiskering but it embeds in the grain. Then after whiskering is done, I paint on a coat without scraping it off and then finish.
dave