Bacon Grease!
I'm in the camp that believes oils are for closed systems, Grease like mine or Slide Glide has been very successful in keeping guns lubed in harsh conditions. I use a NLGI 00 base grease which is the thinnest you can get. won't gum up at 32 degrees, or melt off till it gets to 400. But then as we have seen over and over, opinions abound on the topic, so, to each their own. Good luck.