I have a Mossberg pump that has some rust on the barrel. What's the best method/product to use to get it off wothout ruining the remaining blueing?

Thanks,
Puncher

Use a fine steel wool and gun oil to rub off the rust in the spots necessary. After all bluing is a control rust process. If you use a rust remover like Naval Jelly it will remove all blue down to the metal.

puncher
I have used RB-17 and 000 steel wool, it worked wonders for me

I never use steel wool as a first choice. I always try rubbing it with a penny or using one of those solid copper wool scrubb pads. They are softer and less aggressive than steel wool. If you use some light gun oil with it, you'll never touch the bluing with a copper product. If the rust is deep and the surface pitted, then you may need steel wool, but try the copper method first. I think you'll be surprised how well it works.

Boil it!!

0000 steel wool and kroil. Rust will give it character ...

Boil it. Then use oil and one of the plastic abrasive pads. Anything that will remove the rust will take the bluing off as well.