Eric, it appears you do not use the flushing method of cleaning. Is this so?
Last test I saw on rust preventatives, EEZOX was the best, with Hoppe's #9 Solvent being second best, with Hoppe's Gun Oil being down the list a ways.
Rig was not on the list, so not tested.
EEZOX sure makes metal parts slide nicely. Excellent drying lubricant as well.