How do I remove rust from a gun barrel?

Disassemble and wipe down with a product called Kroil. Make it oily and place on a plastic bag. Let sit for a few hours. Like do in evening, come back after breakfast. With a terry cloth or old diaper cloth rub down well. The built on dreck should come off as gray residue. Keep doing this until clean steel results. Why disassemble? Keeps Kroil off the wood. It will soak in.

If real bad? Get some 0000 steel wool and lightly buff.

Oil lightly to where you just taste oil with a wipe of finger. Reassemble.

I like what the Reaper said.

What you dont want to do is rub this abrasive rust into the good parts of the barrel and damage them.

Go gentle, easy, take your time. Once you have the rust off - there are several Cold Blue products you can use to touch up the areas. Keep in mind - this stuff does a good job on lots of small areas - and - not a very good job on big areas. Birchwood Casey is the one you can find easiest on most gun shop store shelves - worth a try. Clean the area with methanol or alcohol and warm it up with a heat gun, not hot, just warm, and apply with a clean cotton rag or old T-shirt. You can apply again after an hour. Let it set for 12hrs - then buff it lightly with oil. If this doesnt work good enough for you - surf over to www.brownells.com where they have a huge assortment of professional bluing supplies and salts....... and you can always take the barrel to a local gunsmith for bluing or send it out. All depends on the amount of $$ you want to put into it.

Start with an oily rag. If that does not work, get some brass wool. It will remove rust but nothing else. If that does not work, you may want to consider 0000 steel wool. It will scratch/remove the bluing. Use plenty of oil in all cases.

Get some really fine steel wool and saturate it with gun oil and lightly rub it off. Don't scrub, just rub.

Steel wool. Scrape the rust spots with it, if the rust doesn't disssipate you may need a new barrel, but like you said its almost invisable so the steel wool should do the job.

Don't Fear The Reaper is correct.

You may also check this out for confirmation.

http://www.youtube.com/watch?v=GbnBbskMgsc

It is the first thing the mention here w/ a demo of how to do it. Hope that helps.