Re black gas, in freezing conditions its pressure is considerably reduced, yes if you are stupid and use it when warmer breakages will occur.
You are correct Parker gun oil does not contain PTFE or any other modern slippery substance, it is a mineral oil of which its natural properties provide lubrication.
It is also lightweight, so it penetrates, does not clog, and it cleans, it is not a one time treatment, it is meant to be applied and removed with each usage of the RIF just as you would a real firearm.
I mean i havent run MWS's since they came out or anything.