Powder sensitivity over heat variation .308 11 powders

https://www.wlcastleman.com/equip/shoot/t308/index.htm
This is a link to a powder test done ( in the US naturally)
Where you see Varget read AR2208
Where you see H4895 read AR2206H
Where you see IMR8208 XBR read AR BM8208

With a lot of people changing powders due to their favourite flavour being hard to get, this may help a few not to get too excited about loads developed in the summer versus being shot in the winter.

Usually you only get test data on one type of powder, this guy went to a lot of trouble and got the data for 11 powders!

The data is from 2022 so pretty relevant for 2023 still. if you go to his home page he has done research on .223 with 9 powders as well, but I havent read that.

Fascinating! Thks

Great information thanks. Always been a fan of 2208.

I ended up with some VV but ouch $126 hurt for 1pnd of it. It's OK performance but I feel less likely now to bother with RL. You can never find it anyway but the results of this test surprised me. Given RL is so popular here.

Thanks for sharing!

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Originally Posted by T.FOYE

I feel less likely now to bother with RL. You can never find it anyway but the results of this test surprised me. Given RL is so popular here.

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Old RL powders, 15, 17, 22, 25 are more temp sensitive than the newer 15.5, 16, 23, 26,

RL16 is less sensitive than 2209, AR-Comp is a RL powder & less sensitive than 08

ADI powders are cheaper here & usually more readily available

It does say 'generated off quickload' which is to say: old information from the vaccum of an excel spreadsheet.'

One important thing not tested was how these powders went while exposed to real world humidity. What sucked in water and then produced lower MV?

Quote:

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Originally Posted by T.FOYE

It does say 'generated off quickload' which is to say: old information from the vaccum of an excel spreadsheet.'

One important thing not tested was how these powders went while exposed to real world humidity. What sucked in water and then produced lower MV?

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I think humidity tests are a whole other level. Once a bottle has been opened it begins to aclimate to its environment. Such a test wouldn't be able to take relative age exposure into account.
Recording RH (relative humidity) levels during reloading sessions might go some way towards understanding it. And I think that as powder ages it's potency changes, this is in part (to my mind) why we must check powder lots for variance.