So I took my RAW in .22 out for some target practice and it was shooting about 3/4” high at forty yards where I have it zeroed. It surprised me because I’ve had almost no trouble with that on this gun. I zeroed it and shot 48 rounds through it and until I got done it was shooting low. The weather has went from being in the 80s to high in the 50s the last three days. I did some checking and my pellets were going about 15-20 fps slower than they had been which didn’t really surprise me. My question is is that enough to change my zero that far in forty yards or is the temperature change effecting my scope? I keep my gun in the house where it’s about 75 degrees and it’s about 50 outside. The scope is an Athlon Cronus Gen 2 if that helps. I’m just trying to make sure I know what’s causing the change. I’m assuming it’s mostly the speed difference but that seems a bit much. I’m curious what you experienced ones think.
POI change with temperature
- Thread starter Zach
- Start date
Colder air is more dense so pellets will move slower and air will mover slightly slower through the internal ports. oils and greases become thicker but other than that I can’t understand what’s happening, RAW’s are rock solid and do not suffer from parts expanding/ contracting at different rates due to temperatures changes. I have shot mine in -15c with no issues.
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That’s good to know. I am almost wondering if it’s affecting the scope or if something else is happening that I haven’t figured out yet.
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The only thing I've found is a pressure change on the shot due to the air expanding or compressing due to the temp change. But the change has to be relatively large between where I was and where I am. In cold weather I've been able to minimize it by not cocking the rifle until I'm about to shoot it when pesting.
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I haven’t had much experience with that. Will temperature change effect a scope that much? It was 5 clicks which is .5 mil on this scope if I have it right.
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Yep… check out a couple threads very recently posted https://www.airgunnation.com/threads/scope-temperature-shift-fixes.1298422/page-2#post-1582830
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I have a similar combo as you, shooting a RAW with an ARES BTR scope. I have no noticeable POI shift between 50 - 100 degrees with this combo (one of the reasons that i like it so much!). However, this is shooting .177cal and only up to 55 yards. .22cal at longer differences may show the effects of temp shift more???
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That’s good to know. I’m going to keep checking it out. Last night and this morning it didn’t seem to be affecting it like it was a couple days ago. So either it wasn’t the temperature or the new scope is getting settled in or it’s me which is very possible.
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In my experience the cold seems to affect the gun more, and the heat seems to affect the scope more. I don’t even shoot if it’s below 25F. Too many small parts and o-rings that can fail as they’re in a more “brittle” state. If not immediately, then sooner than they otherwise would have. And in the heat I wrap a white t-shirt around my scope to keep the sun from expanding the metal enough to shift my POI.
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As everyone has said, cold temperature shifts effects the scope a lot. As far as your particular brand of scope goes, they are known to have parallax adjustment issues that will throw the shot off. I had an Athlon Helos 6-24×50 that I was always chasing the zero on. It had eventually discovered the parallax adjustment parts stick inside. It was discovered in the cold because it acted up more noticably then when internals or the grease was cold, and would audibly clunk in freezing weather. I sent it in to them and they replaced it, as it is a common issue.
I shoot a lot in the cold, oftentimes well below freezing. I let the gun acclimate to the cold temperature on the bench before shooting it. Also, if a particular gun was only shot in the summer then I will probably have to zero it a little in the cold.
I shoot a lot in the cold, oftentimes well below freezing. I let the gun acclimate to the cold temperature on the bench before shooting it. Also, if a particular gun was only shot in the summer then I will probably have to zero it a little in the cold.
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That’s good to know about the parallax issue because the cooler temperature seems to be affecting that as well. I can easily adjusting zero for colder weather but some of the time it seems I have to adjust every time I go from the house to my range. I emailed them and they said to send it in and they would check it out so I guess that’s what I’m gonna do.
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Temperature, air pressure, and humidity level all affect POI The amount can vary depending on pellet weight, pellet configuration, and muzzle velocity. Its just physics 101. Anything that creates drag will impact POI. More drag, lower POI; less drag higher POI. It is always a good idea to check your zero when any of the above variables change.
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