Just another idea; I use 3M Automotive sandpaper. It's not paper - it's foam-backed. I have both 3000 and 5000-grit. 3000-grit might get the scratches to a more manageable level - then, if it were mine, I would use 5000-grit to smooth it over and set the grain. I picked up an M64 off of here a few months back - I used the 3M stuff and it looks great - especially the barrel...

That said, and I guess a statement of the obvious, I haven't found anything which will exactly match the polishing wheels/compound used by the mothership. The 3M automotive does a better job on Rugers but only pretty good on the S&W's ...