Most of your light synthetic oils with Teflon- RemOil is very good- are good down to 15 to 20 below zero Farenheit. Below that you'll want to run your firearm dry of lubricants or use a dry Teflon or moly powder.
Make sure you completely degrease your firearm mechanism of all old lubes and preservatives if you're planning on prepping it for arctic conditions. And remember to replace all those lubes and preservatives after you're done hunting in the cold.
Most of my business in northern Wisconsin during deer season was degreasing and relubing rifle bolts after the customer had missed a couple of deer due to light firing pin hits 'cause of the cold.
Another problem is condensation. If you take a cold rifle into a warm room, water will condense on the inside and outside. If you don't dry it thoroughly before you take it back into the cold, that water will freeze and can jam the mechanism.
That moisture can also start to rust things. I used to recommend a heavier wax-type preservative for the exterior surfaces. I'd also recommend that the firearms be left in the cold at all times rather than brought in and out of warm areas.
Another bugaboo that will come up in extreme cold is the effects on the chemical reactions of primer and powder. You may get hangfires and weak rounds. You might think about carrying your cartridges in a pocket to keep them warm until you're ready to shoot.
Make sure you check your bore periodically. Ice or packed snow will plug a barrel sufficiently to cause a blown up weapon.
Not exactly a problem here in Texas - 108 yesterday (8/7/03) in Austin, officially, with some areas even hotter.
I concur with the use of dry lubes. "Rem-Dry", "One Shot", and such would be a good start for severe cold conditions. Actually the dry lubes also have the advantage of not attracting as much dust/grit, a plus in any climate. One great features of the Winchester bolt design (and Mausers also) is simple, in-the-field removal of the firing pin for maintainence.
Degrease with brake cleaner (outdoors!). The 'Crud Cutter' and similar 'gun' degreasers are the same thing, in a more expensive can.
Generally I lightly wipe down everything with Break-Free. The bottle claims that it lubricates from -75F to 475F, or for those outside of the U.S., -59C to 246C. Hope I never see either extreme!
If real cold weather is to be incountered I remove all the lube
in my firearms. Another way is to put your greases and oils in the freezer overnight on a pc of glass and see how bad the temps affect them, I did this alot with patching material when I hunted a lot with round balls, you don't want the patch frozen to the inside of the barrel......................Marko
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