Mobil One 10W-30. $$$ Millions of research dollars have been spend on automotive oils and as a class they are outstanding lubricants. Diesel lubricants even have more additives and I am going to try a bottle eventually. I am of the opinion that gun oils are repackaged industrial oils or plain mineral oil without additives. Not worth spending a premium for.
Sorry but gotta take exception to this statement about diesel lubricants having even more additives in them.
I re-wrote the oil specs for our heavy duty (marine and high horsepower) transmissions and worked closely with all the experts from Exxon-Mobil, Castrol (BP) etc. and based on their input we recommended diesel engine oils because they DIDN'T have as many additives as the other oils. These additives cause the clutch plates in a transmission to slip. Too slippery is not good. Normal engine oils have much more additives in them. Now this is for single grade oils and multi-grade oils. The trend, however, is for more additives being added to ALL oils but the diesel oils still have less. The additives in the diesel oil is so the truckers can go many more miles between oil changes but those additives are to extend the time before the "shear" of the additives in multi-vis oils cause the oil to no longer be the heavier grade and NOT to make them "slipperier".
I think I just confused myself!!!