Other than suppressed, full-auto fire, nothing tests a lubricant, a firearm, or a shooter's understanding of lubrication and weapon reliability more intensely - or less forgivingly - than cold weather operations.
We're going to share with you here three key areas to help you maximize your cold weather reliability: Gun prep, how gun lubes behave in cold weather, and actual operations in cold weather.
GUN PREP FOR COLD WEATHER
Carefully clean every speck of non-rated lube off with a solvent first. Non-rated lubes will adulterate proper cold-temp lubes, and shut them down earlier. We use high-percentage rubbing alcohol (91% or better) for all lube cleaning, including on our lab gear and mixing equipment. It's extremely effective, non-toxic, and cheap.
Extra careful attention needs to be paid to fire control group/trigger/sear/striker/firing pin and it’s channel. In general, never lube these places anyhow, but especially for cold temps these are the first places a lube shuts a gun down, as there is a lot less energy moving those parts under spring power, than the slide/bolt has applied to it when a shot goes off.
GUN LUBES IN COLD WEATHER
Every lube has its unique cold-weather tipping point, where it goes from reducing friction, to acting like an adhesive. The more friction surface a gun has, and the "thicker" the oils are, the warmer the temps will be when the lube's adhesion to surfaces and cohesion to its molecules will start creating their own types of frictions, and absorb some of the energy the gun's moving parts need to cycle.
NEVER trust what a "gun lube" company advertises as its low-temp numbers, for two key reasons.
First, every design and chambering combo has its own unique low-temp performance (discussed below), and unique properties in how it will perform with a specific lube. So unless they say "reliable in ___ guns chambered in ____ at ___ temps", it is literally a scientifically invalid and dangerous number to trust your life to.
Second, is that low-temp numbers are the single biggest area of snake oil in the "gun lube" industry. What is usually advertised is what's called the "pour point" - the temp at which an oil ceases to move when turned upside down. It is absolutely irrelevant to "reliable in a gun" temperatures, and is arguably criminal to advertise as the "temperature range" in this application. At a minimum, it is false and immoral. One in particular advertises its low-temp number as -110F, when it is as thick as honey at -20F, and makes common guns unreliable at -30F.
The magic number in chemistry and
physics for cold weather operations is -40F...the world starts taking on bizarre
properties right around this temp, which is about what the battle of Chosin Reservoir was fought at (-37F).
In our R&D in developing our gun lubes, we tested over 80 lubes commonly used on guns on the market, including cold-temp testing. The only common gun lubes on the market besides our Winter Balm that seem to work in temps below -30F are *milspec* CLPs (the only place they shine, and they still fail out at -35F), RemOil, Gun Butter’s oil, and Geissele's lubes. In particular, G's grease is the only grease on the market besides ours we consider safe to stake your life on in having on an AR below -10F. 0w20 motor oils and ATF are good in ARs and 9mms down to about -20F, plus or minus 10 degrees on any given gun design and ammo selection. 10w30 is safe down to about -10F, +/- 10 degrees. Automotive greases and virtually all other NLGI#2 greases shut reliable guns down in temps as warm as 20F. Most "gun greases" are repackaged industrial greases in this grade, regardless of temp claims - don't trust your life to this.
Our Winter Balm is good down to -65F in carbine-gassed ARs, and -55F in Sig 226s in 9mm, which are our standardized testing platforms. When we publish temp numbers for our lubes, it's very conservative - a suppressed SBR will be reliable with the Winter Balm at around -80F, although we don't advertise this. Similarly, we rate our Black Rifle Balm, which was engineered for the intensities of DI ARs, as having a low-temp limit of 0F, to guarantee that no matter what it is put on, it will be reliable down to 0F - but it is completely reliable in down to -20F in carbine-gassed ARs, and -10/-15F in Sig 226s. The difference in engineering greases that are reliable in guns at -20F, vs -65F, is about the difference in technical complexity between putting a man on the moon, and colonizing Mars.
GUN PERFORMANCE AND OPERATIONS IN COLD WEATHER
One of the realities of guns, is that every gun design has its own unique performance in cold weather. The more friction surface it has, and the less power it’s cycling under, the less reliable a design will be with any given lube. A Glock in 10mm will be the most reliable design, while a 9mm 1911 will be the least reliable, just by design and applied energy. Now add to this that every lube has its own unique cold-weather tipping point to adhesion as well. This is critical for any shooter to understand, in making decisions on what lubes to use, in relation to the guns and ammo you're running.
Especially for military, law enforcement, and hunting applications, the following info is additionally important:
Leave guns secure outside - warm/cold/warm creates condensation, that turns into frost and ice that shuts actions down.
Avoid breathing on action for similar reasons. A range day or active shooting are fine, but extended observation or foxhole time can cause frost formation. The AR design significantly mitigates this problem, but stock charging handles, upper/lower seam, and open dust covers can all allow breath moisture to cause internal buildup of frost. As sealing lubricants, our Winter Balm significantly prevents this as well between and around friction surfaces, but it still has its limitations. Lay a cloth over action area if breath will be on the guns for extended time. Same after shooting - the cloth will both help keep the gun warmer longer, and help minimize frost condensation.
Moleskin on stocks is a skin-saver. And on any other place where exposed skin may contact a weapon’s materials. Or other gear, esp metal.
Scope caps save lives - prevents snow occlusion from maneuver/accidents, and for the preferable see-through types, is more resistant to frost formation. This is of critical importance in relation to breath-frost as well. These caps are also easily wipeable with gloved fingers, with less concern about scratches.
In temps colder than about -25F, and especially below -40F, allow the first few shots to warm the gun, firing with 10-20 seconds between if possible, to allow gun materials to warm up slowly. Some materials will be more brittle than others, and extreme differential heating, or simply being too brittle from cold to handle much violence of cycling, can cause part breakages.