The sapwood of walnut is creamy white, while the heartwood is light brown to dark chocolate brown, occasionally with a purplish cast and darker streaks. The wood develops a rich patina that grows more lustrous with age. The wood is generally straight-grained, but sometimes with wavy or curly grain that produces an attractive and decorative figure. With that being said I'd like to suggest "sapping" the stock with acetone before rubbing the tru-oil on. Acetone opens up the pores and would allow the oil to penetrate better into your stock. I work at a cabinet factory as a stain sprayer/finisher and thought I'd throw my 2 cents in. Hope it helps you out!
"It is the soldier, not the reporter who has given us the freedom of the press. It is the soldier, not the poet, who has given us the freedom of speech. It is the soldier, not the campus organizer, who gives us the freedom to demonstrate. It is the soldier who salutes the flag, who serves beneath the flag, and whose coffin is draped by the flag, who allows the protester to burn the flag." -unknown-