What Type of Risk of Damage Does Extreme Heat Pose To PCP Airguns?

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Ezana4CE

Ezana4CE

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Jan 15, 2021
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When I say “extreme heat” I mean 100F and higher. What type of damage can these temperatures pose to a PCP airgun? I have several black airguns and they get hot at shooting table or mounted atop a tripod after being situated in moderate heat (82F - 90F) and sunlight for 20-45 mins or more. Besides perching beneath a tent or shade tree, should I be concerned by the damage that extreme heat can pose to internal PCP components?
 
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It's usually 86°-90°F in my area. I once left my Daystate Huntsman Regal inside my truck in a hard case for 2 weeks out of pure laziness. I noticed it was leaking after I took it out. One of the o-rings gave out. They say that on average, the inside of a vehicle can reach over 40°F hotter than the outside temperature after 1 hour. I won't be making that same mistake again.
 
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Good question , My guns get so hot the metal is very hot to touch, I do not leave them out on the table when I am done shooting , I bring them in and then take them back out when I want to shoot more,, I do not think the heat is good on the O rings , It can be as high as 118 degrees at my table when I am shooting ,
 
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Calculations show it's a potential increase in air volume of %14 (at 60c/140f). Assuming fill temp is 20c/68f... Which in my experience it would be higher, just because the air is heating up as it fills the gun. Factor in that rubber (seals) get softer when heated....

Just another argument for not filling your guns to the maximum pressure rating.

That said, I'd try to avoid prolonged heat exposure, just off of general principal. I'm sure it's fine for what you're doing. Just don't leave them out there. I doubt any manufacturer factored in baking their guns.
 
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The only issues I'm aware of are:

1) Running the airgun in and out of an air-conditioned room. That would cause rapid heat cycles and water condensation inside the gun (but none in your air supply provided it was dry to begin with). This could lead to rust issues.

2) Similarly, if you have o-rings separating dissimilar materials, or even if they don't get uniform experience of the heat cycles you might put some premature wear on some of your o-rings.

I guess if you run your airgun way past it's rated pressure levels, i.e. into "close to failure range" pressure levels, you could have further problems. But I'm assuming you're more or less treating your gun with basic respect.
 
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Was headed out to Co 2 weeks ago from here in Las Vegas. My two SCBA tanks (filled to 4200psi) both blew their o-rings after maybe an hour in the bed of a black truck standing upright. Ambient temp was 105 F. Scary at first until I realized what it was then just a matter of the the proper swear words and all was well...albeit down in air supply. Temps DO drive pressures up a LOT.
Chris
 
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Hard to know, I doubt there is much change in the elasticity of the given components. I think it's a matter of pressures rising beyond what o-rings, poppets and such can hold. In the case of my two SCBA tanks, both of them had thier O-rings blown outside of the tank. At first I didn't know what the black rubber was around the neck of the valve. Completely destroyed o-rings.
It would be an interesting experiment (though I'm not gonna be the guinea pig) to see just how high the pressure goes in a pressure vessel exposed to such changes in temps. Long story short, don't leave your pride and joy out in the sun.

Chris
 
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@ChrisS Seems like sound logic. I’m one to put a field gun to the test, but not without first asking others when I wonder or have suspicions. So far I’ve concluded that I wouldn’t fill my gun to max pressure and take it out into extreme heat. Nor would I want to bring a freshly topped off SCBA tank out in it. I’ve seen the pressure rise in vessels that I’ve taken out and left in the cart or on the table while shooting in high heat. That’s part of why I was also concerned about other components like the poppet and regulator. If the plastic becomes more brittle from heating and cooling during the warmer part of the season, I’d hate to have a hammer smack the poppet (think of a gun tuned to shoot moderate to heavy slugs) and drive the metal through it because poor materials that can’t take the stress of drastically changing temperatures were used. I know it’s speculation, but poppets aren’t cheap if you don’t make them yourself.
 
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It's plenty hot where I live right now, actual temperature in the high 90s with high humidity. I think we only dipped to 80 last night. AC getting a workout. So when I decide to brave it and shoot a little the gun temperature goes up about 20 degrees F. I've checked velocity but the guns I shoot are regulated and I did not see a change in velocity. But while shooting my best 30 yard challenge target last week (my first 200) I noticed the POI had shifted very slightly right - like 1/8th inch. It happened on the 16th shot. I took a break after shot 12 and went inside but left the gun outside. So it had set in close to 100 F temperature about half an hour at that point. I adjusted my POA for the last 4 shots and shot all Xs. So maybe temperature can affect things a little? Like the scope? Or possibly there was a slight wind come up? It was 4 shots which shifted consistently right by about 1/8th inch followed by four shots where I adjusted my point of aim left to compensate and the last 4 were all in the center. So a consistent shift over 8 shots.
 
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JimD said:
It's plenty hot where I live right now, actual temperature in the high 90s with high humidity. I think we only dipped to 80 last night. AC getting a workout. So when I decide to brave it and shoot a little the gun temperature goes up about 20 degrees F. I've checked velocity but the guns I shoot are regulated and I did not see a change in velocity. But while shooting my best 30 yard challenge target last week (my first 200) I noticed the POI had shifted very slightly right - like 1/8th inch. It happened on the 16th shot. I took a break after shot 12 and went inside but left the gun outside. So it had set in close to 100 F temperature about half an hour at that point. I adjusted my POA for the last 4 shots and shot all Xs. So maybe temperature can affect things a little? Like the scope? Or possibly there was a slight wind come up? It was 4 shots which shifted consistently right by about 1/8th inch followed by four shots where I adjusted my point of aim left to compensate and the last 4 were all in the center. So a consistent shift over 8 shots.
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When you have a bunch of dissimilar materials with different rates of expansion/contraction for the same temperature, coupled with different shapes, things are going to move. The block expands, the barrel and shroud move, the scope mounts shift. Honestly, I'm surprised they are as stable as they are.
 
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JimD said:
It's plenty hot where I live right now, actual temperature in the high 90s with high humidity. I think we only dipped to 80 last night. AC getting a workout. So when I decide to brave it and shoot a little the gun temperature goes up about 20 degrees F. I've checked velocity but the guns I shoot are regulated and I did not see a change in velocity. But while shooting my best 30 yard challenge target last week (my first 200) I noticed the POI had shifted very slightly right - like 1/8th inch. It happened on the 16th shot. I took a break after shot 12 and went inside but left the gun outside. So it had set in close to 100 F temperature about half an hour at that point. I adjusted my POA for the last 4 shots and shot all Xs. So maybe temperature can affect things a little? Like the scope? Or possibly there was a slight wind come up? It was 4 shots which shifted consistently right by about 1/8th inch followed by four shots where I adjusted my point of aim left to compensate and the last 4 were all in the center. So a consistent shift over 8 shots.
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All of my 30Y air rifles have ‘slight’ POI shifts shooting 24 bulls. I can’t recall too many cards where I did not get one, two or three POI shifts while shooting the 24 target bulls. I try and get a very precise ZERO at 30 yards, then I “TRY” to not readjust my zero again for wind shifts or other unexplained POI shifts. In other words, I’m trusting my zero.

The reason I do this, is because I end up chasing my 30Y zero when I constantly try to refine a zero,; which might in fact be near perfect. Then I think the wind is moving my pellet and I am not sure why I am getting POI shifts. Is it the wind, is it me, is it my gun?

I think you can go crazy chasing/ readjusting your zero for this challenge. 😀
 
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I agree tommy. Once I am pretty sure my zero is set I do not change it. But if several (like 4) are off a little in a particular direction I may shift my point of aim (POA) a little, A single shot I am very confident is me. Two I start to wonder and think about an adjustment to my POA. But 4 is too much for me to ignore. If I find myself tweaking the scope on the first few cells of a target it normally means I quit that target and save it for future sight ins. Once I get several Xs in a row I don't mess with the scope - but might shift POA slightly. The first four and the last 4 of the subject target were Xs.

My other guns are not as accurate and I don't make adjustments because it typically works out badly for me. I chase the POI around. But my best gun I trust and if I trust myself enough to change my POA a little if it's several shots in a row. I don't even like to change the scope for a fairly consistent wind drift. I prefer just to hold off a little.
 
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