The first thing i'd try is, some BP Blaster penetrateing oil. I'd wet the rust, and let the gun sit over night, keeping it wet. Then i'd wipe it off to see if the rust is gone?

"Heavy" rust will still be there, so the next thing to try is more Blaster, but this time accept some blueing loss, and take a 3" square of aluminum "crumbled" into a ball, and get after the rust soaked with Blaster!! The crumbled foil has little edges that get into the rust and lift it!!

The Alum. is softer than the steel, so you get min. damage to the blueing!! On fly in hunting trips, i always used alum foil and bacon grease! It works a lot better than you'd think!!!

You may have to wipe it off with a cloth, and use more blaster and foil to get all the rust off!!

Give it a try, it works waaaaay better than you would think it would!!

Drilling Man