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Thread: Temperature and POI?

  1. #1
    Sharp Shooter
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    Default Temperature and POI?

    My side wheel has finally arrived so I can now set it up.
    With their being a bit of snow on the berg it was naturally cold at home and it got me thinking, how much does the cold affect the POI?
    A bit of reading proved that CO2 is very much affected.
    The same article (Pyramid Air if I remember correctly) stated Spring guns are too affected, but to a lesser degree, but it gave no hard facts or numbers.
    I would assume that the the greases do stiffen up and springs being metal might harden a touch?
    I saw a scope in the for sale section a while back with a fishtank thermometer on it, so temp must play a role.

    Does anybody have any knowledge on how much a Springer would be affected by temperature?

    My main reason is I am not keen on spending a cold morning ranging and shooting if the click chart is then out when warmer weather comes round.
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  3. #3
    Sharp Shooter
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    Thank you, how do you remember each article in the forum?
    I did a search and I couldn't find that.
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  4. #4
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    Simplify your your search terms. Example: temperature springer - the thread I linked to was the first hit in search results.
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  5. #5
    SAFTAA FT Colours '15
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    You're not going to like me for this, but there are (at least) 3 things happening to cause "The Shift"

    There's the shift with springers due to temperature, which CK pointed you to.

    Then there's a shift caused by density altitude, which the esteemed Piet Breedt describes here : I finally cracked it! - POI shift. ~ Air Rifle SA Forums

    Then your scope ranging may (but in reality will probably) experience a shift as the temperature changes. That's the reason for people putting fishtank thermometers on their scopes. Some shooters have worked out what happens to their scopes in different temperatures and have "solved" it by using pointers that have multiple pins where each pin is used for different temperatures. IME, on the whole, scopes tend to range short (i.e. target is at 48m but the scope says 46m) in cold temperatures, but YMMV.
    Have a look at these : https://www.maestro-design.co.uk/por...cope-pointers You may work out that your scope ranges short below 15, exactly on from 16 to 32, and ranges long from 33. The top pin then becomes your "hot" ranging pin, the middle one your "normal" ranging pin and the bottom one your "cold" ranging pin.

    The unpleasant truth of it all is that there's no way to work out what is going to happen in different conditions without first ranging & shooting in those conditions.
    Last edited by Mark_F; 15-05-17 at 12:13. Reason: Added maestro pointer
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  6. #6
    SAFTAA FT Colours '15
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    Oh, and then there are other factors which affect ranging:
    - People who don't have perfect vision (such as me) tend to need different glasses prescriptions as their "eyeball problem" (whatever the opticians call it) moves over time. This move can take as short as a week or as long as a year.
    - Your blood sugar level effects your vision
    - The colour of the target (and contrast to its surroundings) causes subtle changes in how you see things
    - The amount of light (direct sunlight vs in shadow) changes how you see things
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  7. #7
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    So in a nutshell, you need to be OCD in order to make the Protea Team

    Thanks Mark, so basically to go from a good FT shot to a great FT shot it comes down to experience.
    Knowing how that specific setup operates in different conditions, weather (pun intended) it be wind, temp, altitude etc.
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  8. #8
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    Quote Originally Posted by SnowBeast View Post
    So in a nutshell, you need to be OCD in order to make the Protea Team
    Next level OCD: Internally heated HW100 ~ Air Rifle SA Forums
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  9. #9
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    Quote Originally Posted by Citizen K View Post
    Here I am thinking I will just ask my Mom to sew me a gun bag of a couple layers blanket material and canvas on the outside and a European has invented an actual gun heater. Amazing.
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