Pick up an alcohol based shoe stain called Fiebings at your local shoe repair or leather shop. "Dark brown" is the color you want. Apply it to the sanded stock by dampening a rag with it then wiping it on the wood. If the dye comes with a cotton swab you should practice applying it on scrap wood first or it may get applied to heavy. You want to apply it wet enough to get into the pores but not soak the wood and dye it too dark. It may look orange in the begining but after a few applications will dry to a dark brown with reddish tints. When you get the color that you like any blotchiness can be blended by rubbing a rag damp with dye over the whole stock.
Give it a day or 2 to dry before applying your finish or the stain may lift off.
Chestnut Ridge Military stock stain is about the same product.
This rifle in the photo was done with Fiebings dark brown dye finished with boiled linseed oil.
Good luck with your project. Please email me if you have any questions or want to show off your results.