The above is incorrect information.
Here are the facts for 100% Silicone oil.
100% silicone oil will not effect metal, plastic, rubber or ant other material.
100% silicone oil has 5 (five) main properties:
1) it is very very slippery.
2) It coats almost all materials it comes into contact with. (Silicone oil cannot deal with polar molecules such as fuels, and paint thinners, strong acids and Bases.) None of which are in your air gun.
3) It displaces water (H2O), water moisture cannot exist in a 100% silicone oil environment. It will evaporate or slide off.
4) The SI molecules are so small and tightly packed together the UV rays cannot pernitrate the coating.
5) The operating temp of 100% silicone oil is -58 degrees F to +393 degrees F.
These are the facts of 100% silicone oil.