Load Development in Cold Temps

webs

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Ok so I was looking around and haven't found an answer yet. I know load development is supposed to be done in hotter weather but say you were to do load development with H1000 would you worry to much about the heat? If I find the max load in cold weather and back off a grain or so does one normally see increased pressures in the summer with extreme powders?

I know that some guys keep their cartridges warm when doing cold weather load development. Is this worth it? I believe it will be happening around 20 degrees.
 

Lefty7mmstw

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Ok so I was looking around and haven't found an answer yet. I know load development is supposed to be done in hotter weather but say you were to do load development with H1000 would you worry to much about the heat? If I find the max load in cold weather and back off a grain or so does one normally see increased pressures in the summer with extreme powders?

I know that some guys keep their cartridges warm when doing cold weather load development. Is this worth it? I believe it will be happening around 20 degrees.
I will usually shoot a load in BOTH cold and hot weather before I'm sure it's worth taking afield. I like to see what my stuff is doing at zero (or roundabouts) because the accuracy isn't usually the same as hot weather. The barrel harmonics change a bunch from 0 to 100 degrees and I need to know I'm at useable accuracy at both ends and in between. A load that shoots well at 80 degrees but blows chunks at 10 degrees is useless.
As far as getting a load too hot pressure wise in hot weather when you develop in cold weather; don't shoot for the moon speed/pressure wise and use book data and you will be fine 99% of the time and only a bit warm the rest of the time. Adjust a bit if you are warm; you should have data for lighter charges from load developement. Build a bit of headroom into the load; it's only prudent. Get a big enough rifle to start with.
 
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Mikecr

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I wouldn't buy into the 'extreme' marketing. All powders lite up & vary in burn with different temps. Barrel temps affect the bore and expansions within it. Primer strike is affected with a cold bolt.
Differential expansions of scope mounting with the span of gun heating, causes wondering.
If shooting off bags that are stiffer in cold, the gun might not like that.

In the winter I cycle ammo through pants pockets, and I bring the barrel/action/mounts up to normal temps with foulers before testing. I can fire a bit quicker rate than in summer temps.
 

Lefty7mmstw

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The biggest problem with not letting your gun actually shoot "cold" is the possibility that it will garf when you need if the load won't perform when you've been hiking at zero into a wind and your cold weather gear is frozen to you. You will not be able to get your ammo or rifle up to temp..
 

JackinSD

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I'm with Lefty. I check a hunting load at the extremes and inbetween. If it doesn't work, the fun and search continues. I do use extreme powders and have had great success using them. I want the rounds and my shots to be as close as possible, warm or cold.
 

webs

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Thanks guys. I figured as much. I just got my rifle from the gunsmith. It is a 7mm WSM on a long action with a 28" brux barrel. I am trying to push the 168 gr bergers to 3100 fps. I will start out at 66 gr of H1000 at .050 off the lands. The gunsmith ran a test load of 65 gr of H1000 at .050" off the lands and shot a .40" 3 shot group with shots 5-7. I am waiting until xmas to buy a scope.

Also lefty I know I am getting into the upper realm of the WSM I should have gotten an STW :)
 
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baldoledog

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i like this topic , i think tho it steps out of science and turns into a friendship only time spent will you know what the other will do best friends spent lots of time ( and money ) together
 

webs

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i like this topic , i think tho it steps out of science and turns into a friendship only time spent will you know what the other will do best friends spent lots of time ( and money ) together
Sounds like you hit the turkey a little early this morning! :D
 

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