Fred, I used to brown my barrels that way. I'd draw file, and at most use 180 grit abrasive cloth, then degrease and brown, leaving a matt finish with no carding. Recently, I've polished the barrels lengthwise are far as 320 or 400 grit, carded heavily after each application, and ended up with a very smooth, polished deep brown with more red tones, deep in the steel rather than on the surface.