If you try to polish scratches out of a bead-blasted surface, it will look worse. It could be polished down completely smooth and then blasted again for a uniform finish. Or, you could fully polish out the bead blast effect and leave it shiny or matte. But, if you polish half way through the bead finish it will look horrible.
As far as polishing any piece of stainless steel to remove scratches or swirls: it is a process of rubbing with an abrasive of finer and finer grit until the lines are so fine you can't see them. For example, to get a mirror-shiny surface:
1) Sand with wet-or-dry sandpaper and oil, #600 grit
2) Oil sand with #800 grit
3) etc..... until you get to the finest grit paper you have and the surface appears smooth and flat.
4) Hand polish with coarse rubbing compound
5) hand polish with fine polishing compound
6) Dremel buff to mirror finish with soft wheel using finest polish
Be advised: I spent about 2 hours buffing up the 6" barrel on a magnum so this isn't a fast process and takes plenty of arm. Also, mirror finishes are beautiful but show fingerprints and scratches. On some revolver cylinders I use #800 to lightly buff the SS and leave a matte finish that is easier to maintain. It's whatever looks good to you. Just be sure to understand when you are polishing any surface, you are removing the top layer: bead blast, bluing, nickle, or hard chrome will basically be destroyed. You would then need to strip it all off and restore a finish to the surface.
