Polishing the round section of a barrel is best done lengthwise. If you shoe-shine it, I think the scratches are going to show. Perhaps at 600 grit, maybe not, but I believe that you're going to measures that are unnecessary. I polished the Baker rifle whose pics are below to 180 grit, lengthwise using a piece of pine concaved to the contour of the barrel. I roughed out the pine block with a gouge first, then laid 80 grit, grit side UP on the breech end, and rubbed the block back and forth to grind out the curve exactly to the contour of the barrel. Then I used the same abrasive cloth the other way around to grind machine marks, dings and scratches out of the barrel's surface. Progressed on to 120, and finished with 180. This is my standard finish grit.
I carded the barrel between applications of Neider brown, with a rolled up length of coarse canvas to take away the loose rust, and reapplied the solution. This barrel got five or six 2 1/2 hour trips to the damp box. You can see that the scratches left by the 180 grit cloth have been absorbed and eaten up by the browning solution.
If you polish to 600, card very hard with steel wool, and the colour will be more IN the steel, with a glossier shine at finish...such as you'd do a double damascus gun. The finish on this Baker rifle is very very durable, even, and lovely, and I suspect, authentic.
