Cold weather load development

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by cornchuck, Dec 15, 2011.

  1. cornchuck

    cornchuck Well-Known Member

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    I usually have time in the winter where I would like to go to the range. But it is sometimes too cold to go. But my hunting blind is big enough to fit over the range bench and I can even put my Buddy heater in there too.

    I would like to do more load development this winter. How much difference will see in my point of impacts from cold weather to warmer weather? I know that some powders are temp sensitive but how much of a difference will I see? Should I wait until warmer weather to finish my loads?

    Jason
     
  2. AJ Peacock

    AJ Peacock Well-Known Member

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    As long as you keep your bullets a little warmer, you are fine. BUT, a hot day in the summer and you will see higher pressures. A trick I use during the winter is to toss a couple hand warmers in an ammo box with some cardboard as insulation. If you keep your ammo in there, it will stay a little warmer and will be closer to typical fall weather, instead of deep freeze weather. If you are working up loads for a December hunt in Saskatchewan, let them get cold :D

    You can do the opposite in the heat of summer, by keeping the ammo in a cooler with a couple bottles of ice water.

    AJ
     

  3. Mikecr

    Mikecr Well-Known Member

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    For cold bore load development(once you get there), you will need the conditions that you actually hunt under. There is more than just ammo temps. Barrel and stock temps matter as well. Then there can also be stability changes with your bullets in denser air. Well, this depending on your margin there.

    Just throwin some factors out there.
    I don't develop loads for hot shooting -in cold weather.
     
  4. rscott5028

    rscott5028 Well-Known Member

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    I prefer doing the bulk of load development in pleasant conditions.

    But, as already stated, it behooves you to confirm your dope under actual hunting conditions including altitude, temperature, rests/shooting position, etc.

    And from a safety perspective, you should be careful about developing hot loads in cold conditions and then shooting them when the weather gets hot.

    -- richard
     
  5. phorwath

    phorwath Well-Known Member

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    I think barrel temp is pertinent issue also. When I chronograph loads at variable temperatures in the effort to determine MV variation versus temperature, I sometimes load the rifle and place it in the freezer overnight to collect an ~0F MV reading. Pull it out of the freezer and then fire across the chronographs within 30 seconds of pulling the rifle from the freezer - before too much condensation forms on the rifle barrel and bore.

    Beyond that specific matter, some powders are clearly more temperature sensitive than others, based on the chronographing I've conducted across the 75F to 0F temperature range.
     
  6. LouBoyd

    LouBoyd Well-Known Member

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    The temperature of the rifle will make a small difference but it's the powder and primer temperature at the time of ignition that matters most. The effects of the atmosphere's temperature are easier to calculate than than measure. You can get zero degrees Centigrade with just an ice chest with a slurry of ice and water with the ammo in ziplock bags and carry it to the range. Shoot within a few seconds of taking the ammo out of the ice water and bag. The test is for proper ignition more than for trajectory. Drop is best checked in actual cold weather with sighter shots. It's also practical to use body heat to keep ammo well above ambient temperature until it's time to shoot. Thats an advantage of detachable magazines.
     
    Last edited: Dec 17, 2011