I have always been pleased with the performance of Mobil 1 Synthetic
the fact that it remains present longer without "burning off" after extensive firing/operation
Don't use grease, it makes a gun sticky in cold weather & is tough to remove when it is time to clean
Grease should be used on any moving contact surface
Oil just doesn't hold up and will migrate too easily
Last time I checked, my guns don't have oil pumps!