AR-15 - Extreme Cold Weather Tips?


June 7, 2010, 12:43 AM
Hi All,

I've been thinking about getting an AR-15, mainly because I've never had one and they look like fun, but the one thing I'm concerned about is how they hold up in extreme cold weather - I was out hunting with some guys last winter, it was about 20 below, and both of their ARs malfunctioned pretty hardcore right when a nice coyote showed up 50 yards in front of us. Neither one of them was able to fire - not sure what the complication was, but both had chambered rounds, safeties off, etc. the ARs just wouldn't fire when they pulled the trigger...

Although we never got any closure on what the problem was, I'm wondering what you AR owners think about using them in extreme cold - are there specific maintenance steps you can take to reduce the likelihood of a problem with them when it gets extremely cold out?


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June 7, 2010, 01:06 AM
Any issues with cold weather malfunctions would be due to using too much lube that gels at low temps or maybe letting snow and ice inside the gun by not closing the ejection port when not in use.

Tim the student
June 7, 2010, 01:12 AM
I think FFMedic nailed it.

I've never shot one that cold, but I have shot around zero with no issues. Shot an M1 at about -10 (IIRC) with no issues either.

June 7, 2010, 05:50 AM
I believe the US Military has or had a special lubrication for extreme cold weather, called LAW.

June 7, 2010, 07:41 AM
don't know what the complication was w/ those rifles... i can say that i have taken mine on a few sub-zero hunts and have not had a problem.

June 7, 2010, 08:59 AM
were they able to pull the trigger and the hammer didn't fall?

June 7, 2010, 10:06 AM
If the hammer didn't fall then a frozen trigger group would be the culprit. If the hammer fell then a frozen firing pin would be the culprit. The military does have a special lube for them LAW. I've shot them in -30 (Alaska) with LAW and they never had a problem. I've heard stories about German Mausers freezing on the eastern front in WW2 and the Russian Mosin didn't supposedly because the Russians cut the gun lube with gas or diesel but they may have just went dry as that would seem logical with a bolt gun. If you have the right low temp lube you should have no problem.

June 7, 2010, 12:14 PM
Hi All,

Thanks for the info. Taliv, 45B - yes, they were able to pull the trigger but the hammer didn't fall, that was exactly what happened. I should note that I'm not trying to make an example of the AR, I was shooting a bolt rifle and could only fire one round - the cartridge actually froze in the barrel and I couldn't extract it. That was a pretty easy problem to diagnose though because I had dropped that round in the snow getting out of the truck, then handled it and put it back in the gun without thinking - the case was wet so the consequence should have been obvious if I'd been paying attention.

June 7, 2010, 01:07 PM
Lube becomes a problem when its that cold. You need to use very little lube, and whatever it is, it has to be synthetic. Synthetics tend to flow better when its that cold.

The Swiss's solution is to use no lube, says right in the K31 manual to clean off all the lube and keep the action dry if its that cold.

June 7, 2010, 01:22 PM
Clean all the old lube out of the trigger group with solvent.

Re-lube with Remington Dry-Lube spray.

Problems solved.

As for the cartridge "frozen" in the chamber of your bolt action after you fired it due to it being wet when you chambered it?

I don't know what happened, but that wasn't it.
I would suspect a high-pressure event due to snow or ice in the barrel.
But whatever, the heat from firing would have melted the ice in the chamber and the empty case could not have been "frozen" in the chamber.


Mr. T
June 7, 2010, 01:32 PM
It would be my hypothesis that the firing pin froze up due to too much lube left in the bolt group. Some people think that you have to run an AR sloppy wet; that works great in warm climates, but not so good in sub zero temps. You can run an AR dry(er), especially in hunting like conditions versus combat.

Float Pilot
June 7, 2010, 03:09 PM
Up here in Alaska the AR series of rifles are well known for being a tad touchy in mid winter. The military issue LAW (light arctic weight) lube is a joke compared to other stuff on the market.
The coldest I have operated an M-16A1, A2 and M-4 was around 56 below zero (F) at Fort Greeley. I tried operating a Colt AR-15 at 76 Below Zero at Fort Yukon, but it failed.
Part of the problem is that different metals and plastics contract at different rates during extreme cold temps. So coming out of a house or vehicle at those temps makes all sorts of weird things happen.

Here are some cold temp experiments I conducted a year back.. Using a Stag AR 6.8x43mm rifle, left for 6 hours outside. I have also used some of these at temps colder than 50 below zero on military weapons.

This is only at 20 below zero (F) which is not bad at all.....
In order of how well they worked....

Shooters Choice FP-10...............................Fluid and slippery, adheres to parts during firing

Tetra Gun Lube.........................................Slippery yet gooey. become thick at cold temps... does not flow into small cracks and holes. Great for full auto weapons.

G96 gun treatment spray..........................Very thin, leave a light film. better for bolt action rifles.

Penn Synthetic Reel Oil P/N 92340 Very Fluid, Extremely slippery

Marvel Mystery Oil Very fluid, Very slippery

Arctic Brake Fluid (Syn)...........................Same as MMO, worked well on M2 50 cal.

3 in 1 Oil Fairly fluid, somewhat slippery
LPS-2 Fairly Fluid, somewhat slippery
Klean-Bore Formula 3 Some separation, fairly fluid, somewhat slippery
Tri-Flow Separated, does not adhere or film on metal
Break-Free Separated, somewhat tacky and semi syrup like
Mil-Tech Thick, somewhat tacky, syrup like
Outers Gun Oil Very thick syrup. Tacky
Mil spec MIL4-46000c Lube Oil Separated, some was in thick jell state.
Rem Oil Thick jell, tacky
Boe Shield T-9 Thick Jell, tacky
Corrosion X HD Thick jell, tacky
Ballistol very thick jell. Separation
Exxon Elite 20-50 Syn Av Oil Very Thick, glue like
AeroShell 15-50 Semi Syn Av Oil Very thick, glue like

Shadow 7D
June 7, 2010, 04:20 PM
been there my self, and Greeley is a windy bitch, wasn't as bad as Fairbanks but
if the rifle is hot/cold, you can build up condensation in the firing pin channel
and in the butt stock spring tube.

That is a best guess, because I found that wiping those corrected FTF

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