The purpose of any stain is to color the wood differently from what it appear in nature. What stain you use, and how much of it is used depends a lot on the wood used in the stock.
For instance, I have never seen the reason to stain any Black Walnut stock. The wood is dark enough, and will get darker as any finish you put on it ages( Patina), and is exposed to UV light.
With French Walnut, California Walnut, Circassian Walnut, and others, used for their wonderfully figured grain patterns, covering up those grains with a darker stain is counter- intuitive: ie, why spend all the extra money it costs to buy such wood if you want a stock to be as dark as you can achieve with a cheaper, Black Walnut stock with straight grain?
As for "Rubbing back". A stain is not going to produce something that is Not already present in the wood grain. If a maple stock has "fiddle back" in the wood, staining, or not staining is not going to create more or less of it. "Rubbing back" a stained piece of wood normally refers to lightening the resulting color of the stained wood by lightly sanding or abrading the wood with sand paper, or steel wool.
When shopping stock wood, simply wipe the surface of the wood with a wet cloth to see if it has the kind of fiddleback you want in a gunstock. The water will evaporate quickly, and the wood will look dull again, but you will have an idea of what that piece of wood will appear like when you put the oil finish on the wood.
"BONING" the wood stock after sanding, whiskering, and if desired, staining the wood, is used to close the pores of the wood, and smooth the surface. Boning can sometimes enhance the grain patterns in the wood, but it does not create them. A boned stock feels Harder on its surface, than a stock which is not boned. A boned stock often will not require as much stock finish to fill the pores of the grain, compared to a stock that is not boned.
What a piece of wood will do,or not do usually depends on the particular piece of wood. Always save Scraps from a stock blank when making a gun stock. You can use the scraps to test out stains, and boning, and finishes, before you tackle the finished gunstock.
Good success with your build. We all will want to see pictures of the gun posted here. :thumbsup:
P.S. Natural "fiddle back" is much different than artificially produced "bands" or " Tiger-stripes" created using stains and paints. Natural Fiddle back reflects the deflection of light off the wood as a result of stresses put in the wood during its growing life. With true fiddle back, the "Bands" of stripes actually move back and forth as you change the angle of the stock to your eye and the source of light. That movement does not occur in artificially striped stocks.
The amount of "Depth" to fiddle back is usually the result of several layers of stock finish on the wood, which, when dry, cause a prism effect to the light coming off the wood grain, bouncing the light back and forth between the layers before it comes to the eye. The result is a deep " wet", glassy look, unless you dull the surface of the stock finish using very fine abrasives, like rottenstone, or pumice. The shine or glassy look of the surface can be matted, but the depth of the finish will remain.
