Finally had some time to shoot pellets over the chrony to know my gun better. Not sure if this is normal but I noticed my gun shoots hotter after refilling the gun with electric pump, which gives me a higher velocity shot string compared to the shot string with the gun with cooler air that sits over night. The velocity I tuned for is 870 FPS with cool air but jumps to 900 FPS with air refilled by the electric pump. Is this normal even for a regulated gun? Do warmer air do make the gun shoot hotter? If so, what would be the best way to tune the gun? With the cooler air or warmer air. Hope this makes sense.
Shot String with Cold Air Versus Warmed Air
- Thread starter Archdesigner03
- Start date
So yes, cold weather usually makes pcp shoot slower.
I find it’s easier to not retune. As slower fps with pellets will most likely still be a stable shot.
however, shooting over 900fps with pellets often results in bad accuracy.
I find it’s easier to not retune. As slower fps with pellets will most likely still be a stable shot.
however, shooting over 900fps with pellets often results in bad accuracy.
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I'm sure that someone with more knowledge and experience can chime in better, but there are a couple points that I would bring up. The most obvious is that gas expands as it gets warmer, meaning that your tank has more pressure in it when warm. Your regulator shouldn't care about that and should regulate to your proper pressure anyway, so that point is moot.
Another thing to note is that the pressure is less on BOTH sides of the regulator, since the temp is lower, which may reset the regulator. Frozen condensation could also be affecting the accuracy of your regulator.
Finally, my last thought is that you are gaining velocity at the lower temps because the pressure is slightly lower in your plenum, so there is less pressure against the valve and the hammer is able to hold the valve open for a tad longer...meaning that your gun is tuned well.
I would say to tune the gun in the conditions that you will most likely be shooting so that you will get the most consistent results when you need it to work.
Here is another thread on the subject.
https://www.airgunnation.com/topic/temperature-inside-outside-pellet-velocity-change/
Another thing to note is that the pressure is less on BOTH sides of the regulator, since the temp is lower, which may reset the regulator. Frozen condensation could also be affecting the accuracy of your regulator.
Finally, my last thought is that you are gaining velocity at the lower temps because the pressure is slightly lower in your plenum, so there is less pressure against the valve and the hammer is able to hold the valve open for a tad longer...meaning that your gun is tuned well.
I would say to tune the gun in the conditions that you will most likely be shooting so that you will get the most consistent results when you need it to work.
Here is another thread on the subject.
https://www.airgunnation.com/topic/temperature-inside-outside-pellet-velocity-change/
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I am actually gaining velocity with higher temperature. This sounds normal right? I would think the regular would do is job because pressure is pressure. Thanks for the link, reading into it now.
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Yes colder temps will slow your velocity down. Also really thick humid air will mave velocity change.
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It’s common science any thick air cold or hot will be slower. Any thin air cold or hot will be faster. What ever air source you use to fill your guns try to keep it as dry as possible.
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If your gun is regulated, there should be no change. Regs work on pressure so they will still allow the same amount of pressure into your plenum.
Going from room temp to ~20F I lose about 10% tank pressure but my velocity is not any less than it would be on a similar weather day (pressure/humidity) in the summer. Around 10-15fps difference depending on factors.
Going from cold to hot is a bit of a worry, your air will expand in your plenum and in your tank as it warms. So if you filled it outdoors and then stored your gun indoors, be mindful that the pressure will go up. I'm not familiar with how this rising pressure works in the plenum (between reg and valve), but my thinking is that air that has already came out of your reg does not go backwards into the tank if the plenum air expands and goes from say 2,000psi to 2200psi. I usually take 5 dry shots into my pellet trap when I get home from shooting in the cold, just to let the gun settle back down in room temp air.
Going from room temp to ~20F I lose about 10% tank pressure but my velocity is not any less than it would be on a similar weather day (pressure/humidity) in the summer. Around 10-15fps difference depending on factors.
Going from cold to hot is a bit of a worry, your air will expand in your plenum and in your tank as it warms. So if you filled it outdoors and then stored your gun indoors, be mindful that the pressure will go up. I'm not familiar with how this rising pressure works in the plenum (between reg and valve), but my thinking is that air that has already came out of your reg does not go backwards into the tank if the plenum air expands and goes from say 2,000psi to 2200psi. I usually take 5 dry shots into my pellet trap when I get home from shooting in the cold, just to let the gun settle back down in room temp air.
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