What is temperature limit where you can still shoot PCP?

[Kinetic45]

Although I live on the Texas Gulf Coast where freezing temps only happen a couple of days a year, I've hunted with airguns in Wyoming and in Alaska in winter so had to learn the differences.

1. No petroleum oil lubes that get thick at sub-zero, especially the hammer or trigger mechanism, so I strip it of any and all grease and oil . I used dry lubes (not graphite, graphite absorbs moisture [your bringing it inside right to get condensation on?] and clumps together; also there is a potential corrosion problem with dissimilar metals***, in this case steel and aluminum, which graphite can exacerbate) like dry Moly or silicone spray. I also had very good luck using Hexagonal Boron Nitride (Nickname: White Graphite), desolving it in solvent and applying it to the hammer path where the solvent evaporates and leaves a powder that sticks/coats well and is EXTREMELY slick.

I've had Remoil freeze, but not transmission fliud, Weapon Shield, G96 or FP10... but after trying multiple supposedly arctic rated firearms lubes I found Mobil 1 100% synthetic 5W20 to not congeal at -14 and lubricated well.

Note that Kyrtox (or Ultimox 226) inside the valve is OK at extreme low temp.

Here's a copy paste of something I found back in 2012 and it seems to have been accurate

Alaskan Cold Weather Firearms Lube Test.
Negative 10 to Negative 65 F.

Shooter Choice FP-10..........Works very well in ARs and bolt guns. Good to-50
Terta Gun Lube...........Thicker, works well on crew full auto weapons Tried at 62 below
Mil Issue Arctic Brake Fluid.......Worked well on M-2HB and M-240 at 56 below
G-96 Gun treatment............Comes as a spray, very light, bolts guns to -65
Penn Synthetic Reel Oil P/N 92340..... Very Fluid, Extremely slippery good to -65
Marvel Mystery Oil..... Very fluid, Very slippery good to -40

3 in 1 Oil.......Fairly fluid, somewhat slippery gums at -20
LPS-2.........Fairly Fluid, somewhat slippery gums at -20
Klean-Bore Formula 3....... Some separation, fairly fluid, somewhat slippery

Tri-Flow.......... Separated, does not adhere or film on metal
Break-Free Mil Issue....... 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 below minus 20
Boe Shield T-9.......... Thick Jell, tacky, leaves wax like film
Corrosion X HD......... Thick jell, tacky
Ballistol.............very thick jell. TOTAL Separation
Exxon Elite 20-50 Syn Av Oil.......Very Thick, glue like
AeroShell 15-50 Semi Syn Av Oil.......Very thick, glue like

2. Fill pressures. If I filled inside and went outside where the pressure dropped when cooled off then the FPS at the low pressure was the same as that pressure on a warm day. So if I had 2500 PSI at 0F then it got close to the same FPS at 2500 PSI at 72F, AT THE MUZZLE. So I always topped off at the cold temp to what the rifle was rated for, and if I did shoot at something, shot the rifle down before reentering the warm to prevent excess pressure.

3. Reduced velocity due to denser air so have to compensate I was given this formula by an Ranger sniper and it seems to work: For every 18 degrees drop in temp, velocity falls 25 FPS, Heres a screenshot of how It plugs into Strelok Pro and the app then gives you your velocity at whatever temp you tell it you are shooting at. Of course, this is my gun and the chart only applies to it... you have to shoot yours at a known temperature (have a thermometer with you, not use the weather report or something) and see what FPS you get at your first shot fill pressure. Plug in those values then add up and down from there to fill in the table.

***The issue is galvanic corrosion when aluminum is placed in contact with graphite. The same thing happens when you put steel in contact with aluminum (to a lesser extent). The way to figure out if two items are going to corrode when placed in contact with each other is to consult a galvanic corrosion table. The farther the materials are from each other, the faster the corrosion will take place. Water from condensation or humidity is soaked up by the graphite and becomes the electrolite.

 

[Hubertus]

all my pcp rifles dont need lube in the striker tube. they are running more consistent without any lubrication.

on all other mechanic parts im using nothing or a very small amount of lubing. there is no need for more

 

[Guest]

I'm not so sure I buy this drop in fps as purely a function of air density/temp(rarely tied together in a linear fashion). Loosing 75fps at the muzzle over a 50deg temp shift eludes to a valve and hammer configuration not designed to cope with change. Or maybe your Ranger buddy was reffering to high energy rounds and the extent of thier balistic abilities, not so much pellets or the anemic slugs used along side them. You don't mention chronographing the gun to achieve your numbers either. Or what brand of gun or round being shot. It may also be your stock/gun frame shifting that causes the extreme drop in poi. Or the scope, or it's mounts. So you see I'm not attacking you but trying to fill the holes of your post to better understand your stated results.



As for lube in a PCP im with Hubertus. Polish your moving surfaces and leave it at that. If you insist on Krytox or Ultimox for your springer understand that its function is to stay slicker than snot down to 2k(space). This means it's more effective the colder it gets. Not great if you're looking for consistency over a varying temp range. This I've learned from seasoned, Championship level FT springer shooters. 

 

[oldman70]

I'm going to try wrapping my bottle guns this year with hand warmers this year to get more shots.it might help with moister also and leave my scuba tanks in warm truck.

 

[Kinetic45]

I'm not so sure I buy this drop in fps as purely a function of air density/temp(rarely tied together in a linear fashion). Loosing 75fps at the muzzle over a 50deg temp shift eludes to a valve and hammer configuration not designed to cope with change. Or maybe your Ranger buddy was reffering to high energy rounds and the extent of thier balistic abilities, not so much pellets or the anemic slugs used along side them. You don't mention chronographing the gun to achieve your numbers either. Or what brand of gun or round being shot. It may also be your stock/gun frame shifting that causes the extreme drop in poi. Or the scope, or it's mounts. So you see I'm not attacking you but trying to fill the holes of your post to better understand your stated results.



As for lube in a PCP im with Hubertus. Polish your moving surfaces and leave it at that. If you insist on Krytox or Ultimox for your springer understand that its function is to stay slicker than snot down to 2k(space). This means it's more effective the colder it gets. Not great if you're looking for consistency over a varying temp range. This I've learned from seasoned, Championship level FT springer shooters. 

The screenshot is for my .357 Slayer and the test was done at 78F, measured with a thermometer at the time of the test and ten shots on tether shot over a Prochrono. The information on air density vs how fast bullets slow down is well known but usually it is seen as a function of altitude. In basic terms, as your altitude increases, the density of the air the bullet must travel through decreases, thereby reducing the drag on the bullet. Generally, the higher the altitude, the less the bullet will drop. BUT, TEMPERATURE also changes air density and cold denser air creates more drag on a bullet, causing the trajectory to arc more downward., Lowering POI.

I'd already almost done an encyclopedia post, I thought it was getting too long so Yes, I didn't put everything down I could have

Also, no Springer's in my house, just big bore PCPs so lubrication of break guns wasn't ever anything that crossed my mind.

 

[jdanvers]

lol . . . the shooter in the video @previous page appears to be in much better shape than the video guy. The video guy constantly sounding out of breath. The shooter -- cool as a cucumber. 

 

[Robg7734]

How does the cold of winter affect the operation of the weapon, at what temperature is it safe to shoot to prevent the weapon from breaking?



Coldness, of course, reduces pressure and reduces power, but for example, a hammer, regulator, springs or o-rings could break due to cold?

It's really doesn't. I live in Iowa. During the winter, the manometer on my guns will show a drop of pressure around 10 bar n a really cold day. But it goes back to normal after warming the guns up or firing a few shots.

 

[Loff]

It's really doesn't. I live in Iowa. During the winter, the manometer on my guns will show a drop of pressure around 10 bar n a really cold day. But it goes back to normal after warming the guns up or firing a few shots.

Yesterday, I took out my FX and pressure in tank dropped 30bar, 180 to 150. Temp change was from +20 C (68F) to -11 C (12.2F). 480cc CF bottle.
Pressure drop is one thing but You can't hold your hand out of the glove no more than 3-5 minutes. But there is always shooter gloves available.

 

[bigHUN]

Early January 2022 I got cold ... at my gunclub we have some wood stoves in every sheds, but in-and-outs to -20C, I got bleeding from bladder overnight. Emergency Services picked me up and was sitting in Hospital ER for two days with blood clotting ...Covid time and they had no directions how to handle life treating situations (Canadian liberal rules). Finally got a surgery and visiting the Hospital every 3-4 months for a cameraman to check.
It is not only a gun you shall be worried about when it is cold.

 

[Loff]

Early January 2022 I got cold ... at my gunclub we have some wood stoves in every sheds, but in-and-outs to -20C, I got bleeding from bladder overnight. Emergency Services picked me up and was sitting in Hospital ER for two days with blood clotting ...Covid time and they had no directions how to handle life treating situations (Canadian liberal rules). Finally got a surgery and visiting the Hospital every 3-4 months for a cameraman to check.
It is not only a gun you shall be worried about when it is cold.

Yep! You can buy new gun but no new health!

 

[Jbrownfi]

I drop a lil FPS when I chrono but it’s nowhere close to as drastic as mentioned above. I have however noticed slower fill rates, it’s gets close to filling then hesitates after a couple second or two it’s back to normal. I tend to shoot faster than most people so that could be more the issue, I’m use to send em as fast as ya can get on target. I’d imagine with different metals and everything shrinking up when it’s cold the parts don’t want to move as easily or nearly as fast. I’ve learned to listen for the bottle to tell me when it’s full vs look at the gauge.

 

[jmohme]

Yesterday, I took out my FX and pressure in tank dropped 30bar, 180 to 150. Temp change was from +20 C (68F) to -11 C (12.2F). 480cc CF bottle.
Pressure drop is one thing but You can't hold your hand out of the glove no more than 3-5 minutes. But there is always shooter gloves available.

View attachment 414000

Love the picture, but in all honesty, if it looked like that outside I would move to Texas.........Oh wait, I already did!
I sometimes miss the snow, but then I recall the cold.

 

[bf1956]

I kind of feel like the authority on this subject, being from Southwest Montana. We seem to deal with this problem for about 10 months out of the year. Cold weather affects everything in a detrimental way. Higher ft/lbs, bigger projectiles, anything that requires more air, will be affected more. To add insult to injury, it gets worse the colder it gets. I start to see problems around 45F. I can hunt and shoot pretty accurately but can tell the projectiles have slowed and air consumption is a lot more. At 25F parts are straining and i would definitely not fire off several rounds in rapid succession as some kind of breakage is sure to occur. I could only imagine what kind of wind chill temps are going on inside one of these rifles as air passes around frozen o rings, dissimilar metals expanding and contracting at different rates, or lubes that no longer lube at that temp. We shot a match at Hamilton in March 2017. The temp averaged around 14 degrees, There were some ok scores, but it seemed everyone was disgusted as every rifle (even the springers) were not performing the way they should have been. They will operate, but will fail eventually. Period. I have tried hand warmers on the bottles, made little neoprene jackets for everything to no avail.

I worked 34 years Ironworking construction...in the cold here. We used industrial air compressors that we spent most of the day trying to clear frozen condensation from supposedly dry air....Ha, not at those temps. The humidity is a lot higher in cold weather - typically around 70-95%, so even though you are supplying the rifle with dry air from your tank, as soon as there is any pressure drop or temperature change, condensation will occur and there is nothing you can do about it. Thankfully, i retired and don't have to deal with that. I don't try to shoot my rifles out in the cold too often either, unless of course we get a surge of coyotes or zombies (believe me, it happens here). Nowdays, i spend winters hoping someone from someplace warm will invite me to go shoot with them

. Hope this helps, I gotta go warm up now.

Regards,

The Big Guy from The Big Sky

Iron workers know, it's tough trade but I still love it although haven't done it for along time now. It's like,Man how did we endure? Best time in my many trades.

 

[Loff]

Love the picture, but in all honesty, if it looked like that outside I would move to Texas.........Oh wait, I already did!
I sometimes miss the snow, but then I recall the cold.

Snow is still here and it has been over a week now that the temperature is around -20°C (-4°F). Not much fun. Heavy equipment is stiff, diesel fuel starts to clog up fuel filters, etc.
Today I made a joke to my wife that we have to move to USA Texas

 

[scottblair]

In my limited experience, as I'm currently experimenting with shooting in the cold so I know where my first shot will be when hunting, it effects everything as ironman just said. I found that fill pressures need to be adjusted accordingly, as the 3600 PSI fill from when it was indoors will drop down, (significantly effecting the first shot of unregulated airguns) and when you bring the gun indoors it will build up pressure so that first indoor shot could be adversely effected too. I have yet to find an issue with the o-rings. But internal icing could be an issue, but only within certain perimeters.

Also, depending on the temperature, there is a lot of condensation and/or frosting to the outside of the moderator because it is where the air first expands past the barrel. I wipe it down good before putting it in the case at the range and because both the case and gun have been sitting out in the cold I don't open it up a few hours after home. This allows the inside of the case to warm slowly and keeps the lack of blast of warm air from causing quick condensation. When I do open it I wipe it down and let both sit by circulating air to blow dry anything before putting them away.

This is very true. Let cold guns warm up slowly. I bring them from outside into my basement where the temp stays around 50° during mid winter.

 

[Berserkeley Mike]

Ask a nerd a question, get a nerd answer:

PCP airguns run off compressed air. At the pressures in the bottle, the air is in Supercritical Phase, meaning it behaves kind of like a gas even though it is at liquid density, which is good for consistent performance. Compare that with CO2, which behaves very well when it is warm, above 31C (80-something F), but fussy and weaker the colder it gets from that.
There is a chart showing the relationship between pressure, temperature and the phase of air, called a Phase Diagram; look at the first figure on this page:

Air - Properties at Gas-Liquid Equilibrium Conditions

Properties of air change along the boiling and condensation curves (temperature and pressure between triple point and critical point conditions). An air phase diagram included.

www.engineeringtoolbox.com

Air behaves Supercritical above around 40 bar and -140C (-220F?), and fortunately even though at high pressures gasses tend to become liqiuds and liquids become solids, above -140C air will be supercritical up to around 400 bar. So you might have trouble running your PCP on Titan, but nowhere on Earth should the gas cause troubles.

 

[tnt68]

Ask a nerd a question, get a nerd answer:

PCP airguns run off compressed air. At the pressures in the bottle, the air is in Supercritical Phase, meaning it behaves kind of like a gas even though it is at liquid density, which is good for consistent performance. Compare that with CO2, which behaves very well when it is warm, above 31C (80-something F), but fussy and weaker the colder it gets from that.
There is a chart showing the relationship between pressure, temperature and the phase of air, called a Phase Diagram; look at the first figure on this page:

Air - Properties at Gas-Liquid Equilibrium Conditions

Properties of air change along the boiling and condensation curves (temperature and pressure between triple point and critical point conditions). An air phase diagram included.

www.engineeringtoolbox.com

Air behaves Supercritical above around 40 bar and -140C (-220F?), and fortunately even though at high pressures gasses tend to become liqiuds and liquids become solids, above -140C air will be supercritical up to aroung 400 bar. So you might have trouble running your PCP on Titan, but nowhere on Earth should the gas cause troubles.

Thanks for the link...
Maybe this page gives some answers:https://www.engineeringtoolbox.com/air-temperature-pressure-density-d_771.html