ORIGINAL: outdoorslover
For rust, I just took some Triple O steel wool and some Rem oil. I sprayed the Rem oil on the rust--very heavily, and lightly used the steel wool. It worked great on the outside rust. The rust in the barrel should come out with the oil and brush, like I said. That's the only way I know of.
Outdoorslover,
Get some
Stainless cleaning pads for cleaning rust of the exterior. It is less apt to remove the blueing.
Original: frontier gander
I actually stopped oiling the inside of my barrel, i dont have to do it now that i found a good cleaner.
Since getting stainless, I do not oil the bore. I clean and dry thoroughly. If the stainless is dry, it won't rust. We don't have much for humidity here so its definitely working for me and I don't worry about rust or getting oil out before loading.