Air guns and the weather
Can someone give me a quick overview of how temperature effects the accuracy of an air gun please. I was testing my .25 Matador at 9 am this morning around 60 degrees. I had zeroed the gun yesterday in the evening. Today webt out there shot 3 mags full and got frustrated at how horrible the groups were. Then comes noon and the temperature is up to 73 degrees and back on target with the zero I had set yesterday.
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I live in the lovely Pacific NW where the temp and humity bounce around all the time, and I deffinately notice POI shifts. The worst shifts are when shooting in the winter in sub freezing temps and the Cricket has just come out of a nice warm house. You can just watch the poi shift as the gun cools. The POI drops if I remember right. It’s 55 out right now and the Cricket is a tack driver at 45 yards.
As the air cools down it gets denser. The relationship with the pellet BC changes.
When using the ballistic calculator, change the temperature parameter and notice that the POI will change.
This is also true for high humidity, especally at lower temperatures.
This is less noticeble at short range, but it will affect med-long range shooting.
The better the BC of a pellet the less the trajectory is affected by temperature change.
Cheers
Chris
I have the same situation all winter long except my temperature difference is much worse. Only thing I notice is the the colder it is the more pellet drop you have. I already know what to expect on single digit temps. As far as left to right movements it’s hard to say as you are always compensating for wind you don’t really know what zero is. As I stated before in a post it’s a miracle it shoots the way it does the way I use it.
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Bog, lucky you!! You can keep all that shitty weather.
Donny, maybe that down coat you needed for 60, or the shivering, frost-bitten Floridian fingers affected the groups.
It’s not only the gun that might get affected, the scope can have issues. I’ve gone from room temperature (65-70) into the subfreezing and watched the poi shift as the gun cooled. Strangely, the worst affects seem to be as the gun/scope is changing. Once it has stabilized and all the parts are the same temperature, the effect lessens. After about an hour, the problem doesn’t exist, even at 6 degrees F. That’s because I give up and go inside to hug the wood stove.
We’re expecting a sleet, ice rain fest, starting later today…oh joy.
If someone made a good pellet proof feeder they might make a killing on the airgun sites,, Just saying,
LOL…Coda. I know what you mean. It’s hard NOT to take a shot when they’re sitting on the feeder. One legged birds….. :rofl:
I realize this is completely defunct of the discussion at hand except for the sparrow part. 😀 I just lost another all metal $26 feeder to pellets. Even the .177s eventually get them after about 6 months of heavy fire. I just can’t resist a frontal or back side shot most of the time but it goes right through everything. 😆
Cold climate effects most PCP´s a lot. This is due the aluminium parts shrinking faster than steel parts do. When i speak about cold i mean under 5 centigrade and below. If i zero my gun in room temp , around 20 degrees celsius , and go out shooting in the cold lots of weird things happen.
Lol I am guessing your shots were hitting low! Based in this article from Pyramid Air though, it said PCP are not effected by the cold down to zero drgrees. http://www.pyramydair.com/blog/2005/07/how-does-cold-weather-affect-different-airgun-powerplants/
I was still within an inch but this is only 20 yds away. I am used to seeing hole on top of holes. I was ready to take the matador apart and fux it. Recently lowered regulator down to 100 bars and still shooting 920 fps. Will try try again tomorrow morning and see if results are the dane.
All I can say is I was shooting inside about 75 degrees out an open window at 48 yards , Out side temp was around 30 degrees with a mist in the air, NO wind . I was shooting 1/2 inch to 3/4 inch low , Enough to miss a few sparrows,,, IMO I think the moisture in the air had more to do with it than the cold,,,
I did not put paper out to check my POI , just eyeballed where the pellet was hitting.
Also got a few one legged sparrows showing up….
Mike
:suprisedn: Sparrow Olympics?
60 degrees , You must have been freezing, LOL..
All I can say is I was shooting inside about 75 degrees out an open window at 48 yards , Out side temp was around 30 degrees with a mist in the air, NO wind . I was shooting 1/2 inch to 3/4 inch low , Enough to miss a few sparrows,,, IMO I think the moisture in the air had more to do with it than the cold,,,
I did not put paper out to check my POI , just eyeballed where the pellet was hitting.
Also got a few one legged sparrows showing up….
Mike
Donny, I have not experienced this with my cricket. Did post the other day how much pressure drop I experienced due to filling indoors at around 72 degrees, then taking it out to the deer stand with me while sitting and pressure dropped from 230 bar to 200 and even a bit below… I later returned to camp and brought the gun indoors, pressure went back to set pressure of 230 bar…
When shooting though, I did not notice an y poi shift. I was shooting coons and other vermin and not shooting for groups so there could have been some shift, but not enough to miss a coon’s head or a pig’s earhole…
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Having shot from 115 down to -25 below as well as sea level to 7000 feet I can firmly attest that they both affect POI.
However only vertically once rifle acclimated. Going from warm house of 68 to low teens will show up to 1/4″ horizontal shift at 50 as everything cools then slowly settles back to just a horizontal drop in both my Eds.
Scope,mounts, barrel, tank, wood etc.
Groups will resemble the letter ” Y ” but still well within a squirrels eye.
Just plug in current temp and elevation into Chairgun App and go shooting once acclimated.
It’s normally dialed in at 50* and 3500 feet so I don’t have to click in to much for normal hunting ranges.