Ok so if I keep my Impact in the truck this winter for some pesting and rabbit hunting will the temp changes do any damage to it? How bad will point of impact be affected?
Freezing and below temps
- Thread starter Revin
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Just let your gun acclimate to the outside temperature. Your POI will change in cold weather. Just verify by checking your zero in your actual shooting conditions. My rig in winter.
No damage but don’t be surprised if the pressure drops 10 to 25 bar. Especially if you fill it inside where the temp is warm. POI will most likely drop because cold air is denser and creates more drag on the pellet. The colder the air, the more drop in air pressure and POI.
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I will take my RedWolf out hunting when it is WELL below zero, talking in the -30 or more! The bottle pressure will drop by quite a bit, but everything will still work. Depending on the lubricant you use on the rifle things may get gummy or sticky. Most lubricant cant will seize up when exposed to extreme cold. Though I have had zero issues with the Wolf, my EdGuns and other rifles. They function just fine.
Be aware though that if you top off your cylinder in the cold, and then move the gun into a warm house...... you run the risk of blowing a seal or burst disk! It is typically better to not top off the gun until it has been in the house for a few hours.
Be aware though that if you top off your cylinder in the cold, and then move the gun into a warm house...... you run the risk of blowing a seal or burst disk! It is typically better to not top off the gun until it has been in the house for a few hours.
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In my experience, the pellet (or slug) speed decreases as temperature goes down. Shooting .30 cal JSB 44.75 from an FX Bobcat, tuned for about 880 fps when temp is 75 to 80, the gun shoots at least 20 fps slower when temp is around 50 degrees... Its jsut something that needs to be accounted for when hunting in places where you might start the day at 45 to 50, and end up the day at 80 to 85 degrees...
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Regulator with the plastic (Delrin) piston?
If so, its coefficient of linear expansion is much higher than the regulator body. Meaning it shrinks more as the temperature falls. Shorter piston means it has to travel further to shut off the flow of air. More travel means it has to compress the spring stack more. More compression of the spring stack is achieved at higher pressure. End result: higher setpoint.
The leg bone is connected to the knee bone...
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@L.Leon A picture is worth a thousand words. Nice photos!
@woogie_man I’m definitely interested in your experience shooting airguns in sub-zero temps. Please create post about it.
@Revin When it’s cold outside (>25 degrees F) I tend try to set my rifle outside for about 30 minutes before hitting the woods. When camping before going to bed I have set a rifle on top of a soft case or some sort of fabric (like folded clothes) so that it isn’t just sitting on the tent floor. I may drape something across the top of it or simply place it in an open soft case. I had an incident one night where I was awakened abruptly, rolled over, and grabbed an air gun when a yote started howling outside in proximity to my tent. So ease of access is desired for the unexpected. I’ve also left a rifle in the truck in a case in cool temps over night and didn’t have any noticeable issues. In fact I don’t think I’ve had any issues (other than what’s been mentioned about a drop in reservoir pressure) during or after taking my Evol or EDgun out into freezing temps (20s - low 30s) or light snow to hunt. I like what @Centercut mentioned about a drop in velocity in varying temps. That’s something I haven’t made a point to record.
To find out how your POI is affected try shooting from the same distance, say 25 yards, at various temperatures and record you holds or clicks at each temperature reading to obtain an idea of what sort of adjustments will be necessary during the time of year where temps swing widely from morning to evening or day to night. Hope this helps some.
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Interesting.
Living where I am in high plains of eastern Colorado generally humidity doesn’t vary much unless it’s actually raining or snowing.
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By experience I’ve learned that I won’t even bother shooting if it’s below 20 degrees. Things get all screwy.
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Be aware though that if you top off your cylinder in the cold, and then move the gun into a warm house...... you run the risk of blowing a seal or burst disk! It is typically better to not top off the gun until it has been in the house for a few hours.
Great advise !
Great advise !
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If you only feed your gun Nitrogen there is almost NO pressure change due to temperature variations
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Thanks for all the replies guys, this is the kind of info im looking for and it comes from experience you all have. Keep it coming I'm listening.
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PV=nRT
Nitrogen’s pressure will rise and fall just like air. The benefit of nitrogen is that it is bottled for industrial use to have almost no moisture in it.
The myth of it being less susceptible to pressure change seems to have been born out of marketing claims regarding inflating tires.
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As the temperature drops, so does the gaseous nitrogen pressure per physics laws. However, high purity nitrogen gas produced by gas generators contains less moisture and fewer impurities than air, making it more stable with less erratic pressure changes with temperature drops.
this is about 1 psi per 10 degrees temp drop, very much lower than your wet and Co2 loaded Air
this is about 1 psi per 10 degrees temp drop, very much lower than your wet and Co2 loaded Air
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