I've done a bit of this myself, but wonder if I'm missing something.
My typical method is to chuck the screws in a cordless drill and spin them while wrapping a piece of oil-soaked 600 wet/dry sandpaper around the shank of the screw. No metal removed, but just do this until the bluing is gone and the shank is smooth and shiny. Similarly, for the holes in the hammer, bolt and trigger I wrap an oil soaked piece of 600 W/D around a fine needle file, insert it in the hole and spin it, polishing the inside of the hole. The cylinder pin is polished similarly
The bolt/trigger spring and other surfaces that are mostly flat are given similar treatment. Where flat surfaces are to be polished, I lay the sandpaper on a piece of laminated glass and polish thusly. Flat and flat curved surfaces are usually done by wrapping the 600 grit around a square stone.
I repeat this for a the parts where metal rubs metal.
Is this a generally acceptable method?
Thanks for any input.
CHT