An article I wrote years ago for a pest controllers magazine.
Here reprinted (and updated) following a memory jog from SHTF prepper.
Basically there are four types of air weapons.
CO2 cartridge powered
Out of the four, Precharged pneumatic PCP is probably the best all-rounder in a climate that is predominately wet with a high humidity, with a temperature swing from +30 to -10 Celsius through the year.
Why is this?
Mostly it’s to do with the properties of gases (air, CO2), second lubes in the cold and finally their mechanisms.
Starting from the worse, CO2 powered.
In every case, CO2 is stored in a highly compressed, usually liquid form.
On firing, that liquid is released and expands rapidly back into gas. “Sort of.”
At ambient temperatures of less than 4 °C / 40 °F, the liquid is stubbornly slow at converting back to gaseous form.
Stubbornly translates to a drastic drop in power as much as 50% if not more in extreme cold temperatures. Even worse the more you fire, that expansion of the gas is chilling down the insides of your weapon. Thus eventually, rapid fire can literally freeze the internals of valve assembly, even on warm days.
You’re probably familiar with gas struts that open car boots (trunks) for you.
Same principle, a tad faster, and when filled with nitrogen (the current fad), are sealed for life and internally corrosion free.
They work well, but in temperature extremes the limiting factor is the same as steel springs, the lube used between the air cylinder wall and the gas ram.
Plus their release is harsh. It’s designed to be fast but when we are talking about working with frozen metals, that harshness and loss of malleability due to the cold, it can cause catastrophic failures.
Personally I like springs, low-tech, reliable, especially when topped off with PTFE washers, but the piston can be slowed by thickened greases and lubes round the spring and air cylinder wall. We’re not talking a lot though and a typical figure of 50 fps is the worse that UK weather will cause.
That will push the POI low BUT if you know that will happen, it’s not exactly rocket science to work out by how much i.e. When pest controlling in winter all I do is read the garden thermometer and I’ve got a simple ‘range card’ taped to the stock for sight adjustment. (low-tech stuff).
I mentioned in the gas ram that the release is harsher and faster than a spring piston but in this case the cold sticky grease or lubes on the spring and gas ram kinda softens the metal shock of a piston smacking against the air port. To me that’s good. Not great but good.
It should be always remembered that both spring and gas never do well without a pellet to create that cushion of air and lessen the final smack of the piston onto the gas port.
In extreme cold, that is a VERY important thing to watch. As mentioned, catastrophic metal failure. That’s never happened to me BUT I have seen it happen.
£300 worth of rifle basically scrapped.
So love your weapon and, in the heat but especially the cold, no dry firing please.
Air at 2000 psi is pretty resilient to cold and the stored air in the reservoir won’t lose a lot of force in the extreme of cold.
However there is the question of the trigger, the hammer, and the all important valve.
As a general rule, grease and a PCP is a definite NO-NO.
Compressed air and non-divers quality lubes can cause explosions.
BUT we’re talking about extremes of cold and what lubes you do use generally don’t do well in minus temperature ranges. Thus hammers can hit valves sluggishly if coated and you will lose power accordingly.
Which leaves ALL OF THE ABOVE with a problem.
What to do about the lubes?
In winter I’ve got a simple rule.
All lubes come out.
I degrease everything and apart from a spray of dry silicon, what wear I’m going to incur is going to be minor compared to the damage costs to a customers premises I could incur by erratic power and the subsequent varying POI’s.
In the main, once degreased and silicon’d, any other loses are caused by frozen condensate. That being caused by the transition from cold to hot and back to cold again as I move around.
Thus I keep the weapons in an insulated sleeve the whole time once I’ve chilled down the weapons. The chilling done by storing them outside before my day starts, in the sleeve with a desiccator inside the bag.
Is that enough?
When shooting I’ve usually got a balaclava on which insulates me from the metal and stock, but I’ve never worked out a way of keeping my breath off the stock and bolt actions. At minus 10 Celsius plus, in a close ambient to dew point scenario, that still causes me major problems with bolt actions.
Something I’ve also noticed with shooters who use composite plastic and aluminium magazines on their air rifles. They simply freeze, some crack, a lot just give up.
The rifle(s) all go through a FULL strip down when back in the warm.
Then onto the shelf to be gently raised back to room temperature.
After that it’s a WD-40 moment and everything gets a full dry tissue wipe down and a refresh of the silicon spray.
The wood stock gets a coat of wax, and into the gun rack it goes.
OTT? Maybe but the 15-year-old plus rifles still shoot true, the actions work as advertised, and they look as good as new.
That it? No because I’ve been talking about air weapons.
Firearms are different, sort of.
Here you have four things to deal with.
- Condensate as usual,
- The mysterious art of the cold bore shot at different temperatures.
- You’ll still have treacle minded lubes and greases
- And as metal parts slide against each other, frozen condensate aka ice that can cause all manner of misfires, feeds, and even exploding gas chambers on semi or auto weapons.
Luckily not all oils, greases, and lubes are the same.
Most have a cold weather variant BUT BE WARNED!
Cold weather variants are usually less effective the hotter the ambient temperature gets or the harder the gun works i.e. it heating up in use, with rapid or even burst fire.
Dry Lubes include PTFE, silicon, moly(bdenum), and graphite (which I don’t like as it can attack metals). As such I classify graphite as a ‘sceptical’ lube!
Wet lubes include mineral and synthetic oils and greases.
What causes most misfires or malfunctions?
Dirt, particulates, aka crap!
The sort of fine material that builds up in slide channels, ejector claws, firing pins, triggers, hammers, levers and controls (safety catch), let alone magazine internals.
That and CONDENSATE aka ice which can literally freeze slides enough to hold them shut too long for any recycle mechanism to cope with.
Then there is ice forming inside a barrel.
The 100% certified simple fix for keeping water out of a barrel is the humble condom.
As for what to do about all this?
I read an article saying “A lubes job is to provide a slippery surface for metals to slide on, and ‘hold’ dirt within it thus keeping it away from important things.”
OK, I sort of get that but dry lube sprays simply don’t let particles cling or clump within the mechanism. The only problem there being all dirt falls downwards into the two places you don’t want that to happen. The magazine or trigger group.
Yet I mainly worked with rifles in woods or open fields, and unless the wind is lifting ground debris, the weapon usually comes out clean at the other end except for what it self generates. But not so in winter when you have to add frozen condensate aka ice.
Thus everything gets degreased and I use a dry spray lube.
Which one? That’s the interesting bit.
Here’s a selection of lubes and the minimum temperature they stop working.
(From MSDS Documents)
Molyslip 40% molybdenum (-20°C)
Chain Spray (-25°C)
WD40 the all round degreasant, lube (silicon) and water-repellent. (-20°C)
Which looks great IF YOU CAN GET THEM OUT OF THE CAN!
Generally speaking anything less than 5 Celsius most aerosols stop working.
The propellants, typically Butane, Propane or even CO2, just don’t like the cold.
So what about non aerosol types.
The material you need Silicon, PTFE or whatever is usually mixed with a dispersant that evaporates leaving a film of what you want.
That dispersant can be Ethanol, Methanol, or Isopropyl Alcohol (IPA) to name a few.
Generally speaking, under 11°C, they simply don’t, or take forever to, evaporate off frozen or near frozen metals.
Life is never easy is it!
Thus any in depth lubing I do is in-house or, opening myself up to ridicule, I take a small tube of molyslip and cotton buds in my cleaning kit.
Thus it is not unknown for me to take time out, field strip, clean actions and re-lube slides.
After all when you discharge a firearm it always produces some sort of muck (usually round the breech, bolt face, or, in the case of a piston gas rod, past those ‘indestructible’ (not) gas seals.
As for the trigger groups and bolts?
I’ve never had one freeze up yet but others have.
Their experience narrowed down to frozen condensate aka ice loaded with debris and the general build up of debris you find using dry lubes.