Pressure signs in reloads

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Pressure signs in reloads

Postby Hopalong » Thu Sep 27, 2018 9:29 am

So, I'm working up loads for a new gun, a Henry All Weather in 44 mag. Loaded up a few at the lower end of what the Speer manual recommended and was surprised by the degree of primer flattening. So I poked around on the interweb and found this great article on the progression of pressure signs.

https://www.primalrights.com/library/articles/understanding-pressure
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Re: Pressure signs in reloads

Postby plant_one » Mon Oct 01, 2018 10:11 am

thats a fantastic article.
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Re: Pressure signs in reloads

Postby Hoot » Mon Oct 01, 2018 8:58 pm

I also liked the article about using cheap white rice in a vibratory tumbler. I love the cleaning action using Harbor Freight walnut media but for removing sizing lube, who wants to contaminate their walnut? At about 33 cents a pound in 50 pound bags, who cares if it gets contaminated with lube after cleaning a few batches? Great idea and I'm not using the walnut media much these days now that I have a wet pin tumbling setup. No pun intended but definitely food for thought.

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In Theory, there is no difference between theory and practice. In Practice, there is.
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Re: Pressure signs in reloads

Postby cwlongshot » Tue Oct 02, 2018 5:41 am

Hopalong wrote:So, I'm working up loads for a new gun, a Henry All Weather in 44 mag. Loaded up a few at the lower end of what the Speer manual recommended and was surprised by the degree of primer flattening. So I poked around on the interweb and found this great article on the progression of pressure signs.

https://www.primalrights.com/library/articles/understanding-pressure
Every good manual has a section on "reading" pressures. Primers alone are a VERY POOR choice for pressures..

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Re: Pressure signs in reloads

Postby plant_one » Tue Oct 02, 2018 10:14 am

i agree that they're not the best sign of reading pressure, but thankfully the article addresses issues beyond just reading primers - including but not limited to...

extractor swipes
extractor printing
ejector imprints/rings
pierced primers
case head separation
neck splits
primer pocket expansion
blown primers
primer flattening
primer cratering
heavy bolt lift


as well as a couple examples of false positives of pressure signs - as well as a perfect example of a false negative (the 46gr example)


as it relates to the 450 bushmaster - we've got a known proof point of case head growth as one of the best ways to read pressure signs in this caliber, but it also takes some relatively precise speciality tools to measure it.

so i think that while its not the end-all-to-be-all on reading pressure, this article can be immensely helpful to those who are relatively new into the reloading hobby - and possibly even some of us who have been around the block a few calibers :)
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