Take samples of what you think you want for a patch lube. Stick it in your freezer for a while then pull them out and see which is frozen. If its frozen, you dont want that one. Remember, if it is that cold and your in the field very long, your barrel will be nothing but cold steel and a freezer for your patch lube. Hint, water content is not really good. Lots of greases and oils are no good. Many times wandering the far north in search of game, firearms had to be grease/oil free or you would need a big hammer to break a bolt loose. As far as your lock goes, I would completely remove grease and oil and just lube with pure ballistol and allow it to dry. Lock lube wont really matter as you wont shoot that much.