Go to Brownells and order you a bottle of Oxpho Blue Comes in liquid and a gel I used liquid. Watch a few youtube videos Remove all oil from steel and wear gloves so no hand oil Then heat the barrrel as hot as you can reasonably handle it then apply the blueing agent It might require more than one application depending upon how dark you want the steel. The real color sheen will look better after you re oil the steel It is something you will learn with a little trial and error but you can do it.