Temperature Stability in Powders

Greetings all,
I was re reading some old Handloader mags the other night. This is something I do from time to time to pick up something that is relevant to what I am up to or regretfully more common these days have forgotten. Anyway I found an article by John Barsness on his testing of velocity differences with various powders and cartridges at minus 18 degrees C and 21 degrees C. His testing was done with both the cartridges and air temp at those levels. Perhaps unsurprisingly the ADI powders scored well and the wooden spoon went to milsurp 4831 with a loss of close to 150 fps. Some powders also changed their 100 yard zero for both elevation and windage with the results varying by cartridge and powder.
So if you were wondering what to do on some of those cold clear and calm winter mornings coming up you could do some testing. Let me know how you get on, I will be keeping warm inside.
Regards Grandpamac.

Stick to ADI powders, and keep harvesting deer as far away as you can see them

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Greetings,
I have been doing the first bit for some time but at 76 in two weeks I am having some difficulty with the second.
GPM.

Nort hemisphere temp stability data always seems to look at the impact of extreme cold. Not so relevant for us if it’s below 0 F.

What I have found that is of significance is temp stability in the 35-42 C range. Not unusual in summer to have ammo at this temp due to ambient temp, sun exposure, hot chambers when on the range or in the field.

Some reloader powders in particular RL22 will produce variations up to an extra 150 fps in a .25/06, .270 loading.
Obviously accuracy and precision depart the room.


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Originally Posted by 7mmsaum

Stick to ADI powders, and keep harvesting deer as far away as you can see them

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that recovery looks treacherous.