Listed temperature ranges of various lubes tested -
Break-Free CLP -40 to +475 degrees F
Corrosion X -30 to +350 degrees F
Tetra Gun grease -100 to +750 degrees F
TW-25B -90 to +450 degrees F
Militec-1 -75 to +715 degrees F
G96 Gun Treatment -50 to +350 degrees F
George will have to enlighten me as to the listed temp range of Weapon Shield.
The funny thing about these temp ranges is that most if not all WILL NOT match your results in actual use. Break-Free CLP has caused functioning problems with some troops in Alaska in -30 degree F temps, for instance. Sometimes manufacturers will list the pour point as the lowest temp rating, sometimes they use some other method, but very rarely will they actually test their products on actual firearms. There are of course variables like the amount used, etc. that play a big effect with some products at a low temperature.
I stuffed several lubes into a deep freeze and left them there for two days, to see what effect -5 degrees F would have on these lubes.
G96 Gun Treatment - no change in viscosity.
Rem-Oil - no change in viscosity.
Weapon Shield CLP - thickened up some, but still pourable.
Militec-1 - thickened up quite a bit.
Mobil 1 0W-40 - no change in viscosity.
Corrosion-X - thickened up a small amount.
Mpro7/Hoppes Elite gun oil - thickened up a small amount.
Break-Free CLP - no change in viscosity.
Ballistol - thickened up some, but still pourable.
All of these lubes would work fine at zero degrees F provided you used them sparingly i.e. a thin coat. If you want something that will not change in consistency at all down to -40F I would go with G96 Gun Treatment.
High performance products like Weapon Shield and Militec-1 require only a very thin application to be effective, and can almost be wiped dry, except where more protection from corrosion is required. This compensates for the changes in viscosity to an extent, and it can be pointed out that a very thin coat of these lubes will probably work better than a heavy coat of Rem Oil or other lube that is a very thin petroleum based product.
I tried Ballistol, Mobil 1, and Weapon Shield out on two Glock pistols, cleaning and lubing them, then placing the pistols in my freezer for 24 hours. All three lubes worked perfectly - the pistols fed and functioned fine.
The biggest surprise for me was how Mobil 1 did not thicken at all. It held its viscosity better than Militec-1, which I thought would never happen. That's the second time I've been impressed with motor oil.
In the tests done back in 1996 by the RCMP, they found Eezox, G96 Gun Treatment, FP-10, and TW-25B to be the best lubes for low temperatures. I have no doubt these products would still work well, and I imagine that Weapon Shield would be on the list if tested by the RCMP today, as it would no doubt be a better performer than the older FP-10.
The biggest problem that occurs is when you take your weapons from a very cold environment to a very warm one, without an acclimation period. It is best to leave cold weapons outside when possible. The condensation will turn to ice and slush and this is what normally causes malfunctions in my experience. Just because the lube doesn't freeze doesn't mean the water inside the weapon won't.
Just my thoughts,
Clay