Thank you,Wuchac,for some digestable info.
A light oil I am familiar with is Texaco Regal.It is rated as a light hydraulic oil and a steam turbine lubricating oil.It is what I an accustomed to using for spindle oil in lathes and grinders.
As I recall from exploring catalogues like Manhattan supply and Graingers,one can get great low temp properties out of synthetic greases,and that is why I have been using a sky blue synthetic grease from Castrol as my gun grease.
Having said that,I just examined a cartridge of OMC Triple Guard grease.I don't know the base,but OMC is Johnson/Evinrude Marine.It may be a reasonable choice.They claim salt water corrosion resistance.
The old standby RIG gun grease (Rust Inhibitive Grease) is formulated for preserving guns.A piece of shearling fleece anointed with some RIG is a trustworthy wipedown,and a rig patch will preserve a clean bore.
Just be sure to wipe it out before shooting.