I read with alarm, a few posts back, that one blogger never went to the range without his chosen gun lube in order to prevent malfunctions. In the experience of this hoary, embittered old observer, however, far more malfunctions are caused by gun lube than the other way around. This is because most lubes attract dirt, and because they gum up or freeze in cold weather.
In 1973, I was hunting in Montana with a rifle that had a Canjar trigger that was, like all fine triggers, made to very close tolerances. I had happily honked it full of gun oil, and when the weather went down to -20 degrees, the rifle refused to cock; the bolt rode right over the sear and into the locked position with the firing pin pressing on a live round. Such fun!
I had to take the barreled action out of the stock, pour boiling water through the trigger until it unstuck, put the rifle back together, and re-sight it. Such joy!
Since then I’ve looked with a jaundiced eye at all lubes. Without exception, their labels state that they can be used anywhere from the surface of Venus to the summit of Everest without freezing or losing viscosity. That’s what the labels say. The reality is somewhat different.
If you’d like your rifles to function, keep them clean and keep the oil off them except for miniscule amounts, or altogether. I wipe off the bolts with a patch on which I’ve put half a dozen drops of Rem-Oil (which I mistrust less than other lubes). This gets the powder fouling off, and let me tell you, if you’d like to see a rifle come to a grinding halt, just let the powder fouling accumulate on the bolt for a while. I also run a lightly-oiled patch through the bore and follow it with a dry one to get nearly all the oil out.
It’s a good idea to periodically take the barreled action out of the stock and wipe the oil off the receiver. Since you didn’t put it there, how did it get there? Because the First Rule of Oil is, it goes where it wants to be, not where you want it to be. Before you put the gun together, run either lighter fluid or Birchwood Casey Gun Scrubber through the trigger. If you use the latter, wear safety glasses because if you get it in your eye and you live in Walla Walla, Washington, your shrieks will be heard in Intercourse, Pennsylvania.
And there should be no oil, ever, in scope base screw holes, or on the ring or base screws. None.
For some firearms, you do need a little lube. There are a couple of spots on my beloved Smith & Wesson Model 41 .22 auto where the slide contacts the frame. I put the merest scintilla of an iota of Break Free on a fingertip and apply it where the bluing has rubbed away. On my trap gun, I use white (lithium) grease, that you buy at the hardware store. It stays where you put it even when the gun gets too hot to touch.
If you’re looking for gun lube that will stand up to truly cold weather, I understand there are two. The first is Lubricant, Arctic, Weapons, which is issued to the armed forces and is not, as far as I know, available to civilians. The second, which you can buy, is Renewable Lubricants Bio-Arctic Oil. I haven’t used it, but the maker claims it’s good down to 50 below, and if you’re willing to hunt in those temperatures, your rifle freezing is the least of your problems.