Hmm- thought I had posted to this, just ahead of Rule303's last post.
ATF- the original synthetic oil.
I have used Amsoil 2 stroke oil as a lubricant in the winter time. Like their motor oil & even their gear oil, the 100:1 synthetic 2-stroke oil stays liquid at temperatures no one hunts at.
The coldest for me was -56F on a moose hunt. Trigger and lock worked fine, but I was concerned over the main spring breaking.
That happened to some of the guys at a mere -40. Yeah - we quit that foolishness.