My suggestion is buy some RIG and a sheep skin.Everytime you handle your guns wipe it down with the RIG saturated sheep skin.I agree the Bluing pens aren' t much. I found 44-40 Cold Blue is the best I' ve ever used.Brownells sells it. You might try to find it locally though. UPS has added a HazMat charge for shipping it.I hope you can stop your rusting problem.
Ruger Redhawk