Optimum % of moisture in powders

[MikeRu]

This is from the Hodgdon FAQ site, recommended to store at 50-65% RH, too dry can give more static electricity, single base is more hygroscopic (attracts water) whereas double base is more resistant (more plastic-like due to the added nitroglycerin).

FAQ – Hodgdon Powder Company

hodgdonpowderco.com

 

[Ahhnother8]

Yes, it matters greatly. These hygrometers are quite useful.

Amazon.com

 

[Fast14riot]

@Keith Glasscock did a video about this not long ago. I don't remember if it was public or subscribed content, but maybe he'll chime in.

 

[Capt. Oblivious]

I have all my "opened" powders stored in large sealed containers with Potassium Carbonate (K2CO3), the potassium carbonate maintains a humidity level of around 43-46% and the powder stays very consistent. To dry powder out just leave it in your dispenser for a week or 3, the dryer the powder the faster it burns.

 

[Codyway]

 

[neckturner]

Is there an optimum percentage of moisture when loading or even storage of powder? IS THERE SUCH A THING

In addition to what has been said, most of your questions, and practical outcomes, are addressed by Litz in his "Modern Advancements in Long Range Shooting", volume 3, chapter 7. Great series, recommended reading. Vol III: https://thescienceofaccuracy.com/product/modern-advancements-long-range-shooting-3/

 

[Mulligan]

View attachment 1629981View attachment 1629982

It is interesting that the dual based powder I referred to in one of my posts above was VV-N530. As it turned out it lost the least amount of weight and had the lowest increase in velocity.

CW

 

[Webster]

Sort of,

What I am saying is this.

The powders I tested, were about 80% normalized in 15 min. (By the way, I did test a dual-based powder just to see how it would react, and It changed the least of all the powders I tested).
I do not know they would respond in say a 75% RH environment?
What I can say it they dry out fast in the arid climate of the intermountain west.

CW

Did you determine how fast dry powder would pick up moisture wt. once it's exposed to room humidity?

 

[F Class John]

This is a good read on the subject with some good testing that was done.

How does humidity affect powder?

You may have heard about a relationship between humidity and bullet velocity either in a book, on a reloading forum, or from a crusty benchrest shooter right after saying they get better ES/SD&#821…

chronoplotter.com

 

[Mulligan]

Did you determine how fast dry powder would pick up moisture wt. once it's exposed to room humidity?

Sort of......
The single base powders had about a 15-20 min response time to 80% normalized, both ways. I say sort of because I did not run the same powders through all the same paces in a moisture environment. We do not get wetting events very often here in the desert southwest (8.5" moisture a year here). I plan to do this test this spring.
The dual base powder (N-530) that I tested was a touch slower.

In wildland fire speak, we call that timelag. i.e. a one hour timelag fuel model will normalize to the environment in about one hour.

Using that jargon, single based powders are about a 15min time lag or 1/4 hour timelag fuel.

CW