Caution in the cold

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Cold Trigger Finger, Jan 31, 2019.

  1. Cold Trigger Finger

    Cold Trigger Finger Well-Known Member

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    At the risk of starting something.
    But because I've experienced the results I will share this.
    With this batch of cold temps in the lower 48. Some may want to brave the cold and see how their rifles and other firearms handle the cold. True , Cold . 40 below ambient type temps.
    Rifle barrels, being made from round , steel alloy . they contract in the cold. The colder it gets , the more they contract.
    That contraction / making the interior dimensions smaller. Jacks the pressure WAY UP.
    I imagine most long range hunters and shooters use temp stable powder and often magnum primers to get good ignition and lower SD.
    Which can spell disaster when a load that produces full SAAMI spec pressures with normal ambient dimension s . Is fired in a much smaller chamber and barrel.
    Anyway.
    I just hope everyone is cautious.
     
  2. elkaholic

    elkaholic Well-Known Member

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    That's a good point! I've always wondered when people report some powders have higher pressure in cold weather if it was always the powder or barrel contraction?
     
  3. Canhunter35

    Canhunter35 Well-Known Member

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    I’ve havent seen pressure shooting at -40, but I’ve sure as heck noticed that even varget and h4350 will really drop off in velocity, some where’s around 150fps
     
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  4. KyCarl

    KyCarl Well-Known Member

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    It's best to stay by the fire! Warmer days are coming. It was -5 last night and that's cold for here!
     
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  5. Doublezranch

    Doublezranch Well-Known Member

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    In North Dakota, Long Range rigs stay in the house in the winter. We just finished a stretch of -55 to -60 with the wind chill. These temps aren’t necessary out of the norm, but they only happen every few years. The other thing that happens is those long heavy barrels condensate and sweat like crazy. I’m not a real big fan of watching the condensation drip off a 400-500 barrel.
     
  6. the hunter

    the hunter Well-Known Member

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    So your brass case would contract to?
     
  7. hunter67wa

    hunter67wa Well-Known Member

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    lol you read my mind. went out and shot at 7 degrees the other morning to chrono my rifle and it was fine will shoot it at 80 this summer to check my powder sensitivity. No wind and sunny. Once temp hits 0 its no fun anymore.
     
  8. Ndfarmer

    Ndfarmer Well-Known Member

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    Not saying it can’t happen but I have coyote hunted with 223 and 6mm Ai in -30s and never seen anything. It wasn’t best hunting, dogs lay low when it’s that cold but it’s better than not hunting haha
     
  9. ShtrRdy

    ShtrRdy Well-Known Member

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    Copper and lead would contract too. Do standard chronograph even work properly at below zero temps? My magnetospeed doesn't work properly when the temps are teens to single digit.
     
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  10. hunter67wa

    hunter67wa Well-Known Member

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    My magneto speed worked just fine at 7 degrees
     
  11. johnwm

    johnwm Member

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    This is the best coyote hunting weather imaginable, IMHO. I find they are much more active during these temps; they are burning through calories simply not freezing, and they need food and lots of it. I was out several times over the past couple days during a local temperature of -40C (which is also -40F, it's where the two temp scales intersect). A couple hours at a time is all I can handle; I got a couple shots each morning, scored a few nice dogs. No problems observable, other than being dang cold! Windchill was right at -59C one of those mornings...that's about -74 American degrees. :)

    Last winter I did some shooting in the extreme northern part of my province (Manitoba) at an actual temperature of -59C...thank goodness the wind was uncharacteristically still.

    I honestly think you folks are just looking for an excuse to stay indoors. Your barrel has contracted due to the cold...so has your bullet, and everything else. Can anyone actually produce documentation of a problem caused by this?
     
  12. TGVet

    TGVet Active Member

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    North Dakotan's
    Pray for global warming in winter.
    Pray for global cooling in summer.
    :)
     
  13. Ndfarmer

    Ndfarmer Well-Known Member

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    I seem to have best luck the day after a really cold streak. Johnwm do you have problems with crunchy snow when it’s that cold and zero wind? It’s almost like the sound travels for ever.
     
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  14. tankgijohn72

    tankgijohn72 Well-Known Member

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    Good news! The brass, and copper will contract at a faster rate than the steel. Add clothes. Keep shooting. BTW. Good dedication at -40. My dedication drops around -10.

    https://www.amesweb.info/Materials/Linear-Thermal-Expansion-Coefficient-Metals.aspx


     
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