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Powder burn rates

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Rifletom
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Re: Powder burn rates

Post by Rifletom » Tue Mar 23, 2021 9:33 am

Vaquero wrote:
Mon Mar 22, 2021 10:03 pm
Rifletom wrote:
Sun Mar 21, 2021 8:51 pm
Hmm. I'd hazard a guess that the labs doing the testing, Speer, Lyman, Hornady etc, probably had different "lab conditions", whatever that might have been. Powder manufacturers probably keep said information close to the vest. Trying to figure all that out will be something of an adventure. It's why I cross reference powder manuf website data with manuals. Been safe so far, but I don't load hot for anything. Baffling, I know, but, there it is.
Ditto Tom's answer, with one expectation, my Marlin 308 MX.
It is the only firearm that is loaded to a near max load with either CFE 223 or LVR and 170 gr. JSP's by, Speer or Sierra.
But these loads were worked up, and it is where it is the most accurate.

RP
Yeah, some loads just like being near or at max to perform the best. My 30-30 with W 748 may be my only exception.
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220
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Re: Powder burn rates

Post by 220 » Tue Mar 23, 2021 3:36 pm

You need to keep in mind that the burn rate of powder batch to batch can and does vary.
It is the reason manufactures recommend reducing loads back to starting levels and working up every time you move to a new batch of powder.

The difference in charts is very easy to understand when you take batch to batch variation into account.
Powders can easily swap position depending on the batches being tested.
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220
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Re: Powder burn rates

Post by 220 » Wed Mar 24, 2021 8:10 am

Did a little searching after my previous post as 4% variation rang a bell as the industry standard.
Couldnt find much but a couple of articles did state what I thought I could remember that being 4% is the allowable batch variation for powders.
Still not sure is the 4% is plus/minus from standard or total spread either way it explains most of what has been discussed.
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