Maintaining Critical-Need Reliability under Extreme Cold Conditions

January 18, 2019 By Allan Jones

As you read this, you may be well into preparing for winter hunts. When considering cold-weather gear like shelter, clothing, and footwear, do you include your firearms and their related gear? Will severe cold affect them? Now is a good time to ask that question.

Whether while hunting or in a self-defense situation, your firearm must work flawlessly. Gunmakers build for maximum harsh-condition reliability, but the bottom line is you are responsible for maintaining critical-need reliability when it is frigid outside.

My first exposure to cold weather issues with firearms developed in my early years at the Dallas Crime Lab. Even Dallas, Texas, could experience bitterly cold January days. Being accustomed to warmer weather, police officers too often misjudged the effect of cold on their firearms and ammo.

One visiting officer requested a routine mechanical check of a back-up S&W revolver he kept under the seat of his personal vehicle. The thermometer on the outside of the lab building never recorded higher than 22 degrees Fahrenheit that day.

My first clue to a serious issue occurred while he unloaded the sidearm. The thumb latch was sluggish, and he had trouble swinging out the cylinder and ejecting the live rounds. When I was handed the revolver, it was ice-cold. With some difficulty I cocked the empty revolver and snapped. The hammer took a full second to fall—think “one, one-thousand.” The hammer fell so slowly that it could not have set off the most sensitive primer.

The officer was gobsmacked. He asked what was wrong, and I suggested that removing the sideplate would reveal a wad of stiff grease. I was right. The interior was packed in grease having the consistency of peanut butter. The officer’s response was that it made the action smoother. Maybe, but not at 20 degrees F.

We scooped out the grease and flushed everything with a spray solvent and used a stiff parts brush to finish the job. We left the revolver lubricant-free, and it ran smoothly even after we chilled it in the lab’s freezer to duplicate the conditions under his car seat that morning.

Oils and grease can work against you in extremely cold weather.

I think a well-designed firearm should be able to work flawlessly without lubricant in the internal mechanism, and a number of major gunmakers seem to feel the same way. Back in my carrying days, I would set aside time around Thanksgiving to disassemble my Colt Government Model all the way and remove any trace of grease or lube that may have accumulated. I didn’t over-oil, so there was seldom much to remove, but sometimes I’d find old lubricant hiding in spaces that a routine field-strip cleaning would not reveal.

Some people seem concerned that a new gun must be lubricated, thinking those new parts aren’t yet accustomed to rubbing against each other. I say the best way to avoid lube in that situation is to take the firearm out and shoot it before relying on it. It’s little different from break-in procedures that carmakers once recommended—but a lot more fun. If you run 200 to 300 rounds of factory ammo through a new, quality handgun, the moving parts will make friends with each other pretty quickly. One wise old Smith & Wesson armorer I knew called it “marrying the parts.”

If you believe you must lubricate a firearm headed for cold conditions, consider a dry lubricant. Graphite is the classic dry product but newer ones using molybdenum disulphide (MoS₂) are excellent. Some are suspended in a solvent for neater application. For years I’ve used only Dri-Slide, a suspension of MoS₂ and graphite in a quick-evaporating solvent, on my lightweight Colt Commander. I reasoned that a steel pistol slide running on aluminum frame rails could use a little help. I dribble a little Dri-Slide on a fine-tipped paintbrush and lightly paint the slide and frame rails.

In temperate weather I use light machine oil when needed, applied very stingily with the application pin fitted to a wonderful surplus tool: the U.S. GI Oiler. No big drops that way. Lacking a GI Oiler or similar gadget, you can use any metal or wooden rod. Dip the tip in oil, shake off any excess, and then touch the rod to the part needing lube. That’s all you need. I never touch the oil container directly to the part needing oil.

What about ammunition? Most smokeless propellants will produce reduced pressure and velocity at low temperatures. Research that Sierra Bullets performed came up with a very rough approximation that you lose 1 fps of velocity for every degree the thermometer drops from the reference temperature. For example, a load achieving 2,900 fps at 70 degrees F should post about 2,880 fps at 50 degrees. However, some of their actual data points out 0 degrees F showed reductions up to 200 fps, which is more than enough to affect bullet drop.

Tests at CCI-Speer concluded standard primers worked well to about 20 degrees F but suggested reworking the loads with magnum primers if you know the temperature will be below that. At terribly low temperatures a cold cartridge may not work at all. I spent time with officers from the Royal Newfoundland Constabulary who said they tried testing 5.56mm rifles outdoors at about -40 degrees F and bullets traveled only about 50 to 75 feet, and the snow was covered in partially burned propellant!

Don’t forget your “tech.” Gun sights with illuminated reticles, rangefinders, GPS devices, phones, and radios all rely on batteries that are notoriously cold-sensitive. In the event that cold zaps your batteries, have a back-up plan. Make sure you can still use the sights if the reticle illumination stops working. Other items will fare better if carried under your coat where your body heat helps keep them closer to optimal working range. Carry your spares someplace warm, too.

Remember, if gunmakers wanted us to pack firearms with lubricant, they’d have installed grease Zerks!