I have had great experiences using Formby's Tung oil satin finish. Goes on very wet, flows well leaving no streaks, and has such a small percentage of solids that when dry it is thin but very durable. Gives great depth to the barrel coloring. Also is the very best finish for engraved actions, not filling the engraving with gunk. For actions I use a 3/8" camel hair artist brush but for barrels a folded patch cut from a blue shop towel works best--no lint! I thoroughly degrease with acetone or lacquer thinner paying special attention to the crevasse where the rib meets the barrels. Best not to apply too thin but not so much as to run. Dries in one day.
Sauer 12 gauge sidelock circa 1895 treated with Formby's.
