I have seen pistols which were beautifully finished yet they left the feed ramp rough. I almost wondered if they did it on purpose but don’t think they did.
I used to have a cratex point for my dremel tools which was perfect for polishing feed ramps. I finally used it up and haven’t found another one except as part of a complete set of bits. It would really polish them without removing any metal to speak of.
On their website, it looks like you can buy mandrels and tips separately?
http://www.cratex.com/cratex-cones/