Daily Bulletin article regarding humidity and powder performance.

[Tommie]

http://bulletin.accurateshooter.com/2020/02/how-powder-moisture-content-affects-pressure-and-speed/
I’ve often wondered about the effect of humidity and powder performance. Maybe I missed it in the article, but during the before and after tests was the powder measured by weight or volume? Seems obvious that water “saturated” powder weighs more. If this is the case then wouldn’t measuring by weight result in more actual gunpowder being present in the dried powder test lot? And the next question is - does moisture content actually affect powder performance?

 

[T-shooter]

Would be interesting to take a loaded case (powder only), weigh it, and put it outside someplace protected on a really humid day out of the sun, and weight it again in a few hours or the next day.

I heard all kinds of stories about primers. I took a couple and soaked them in water for a few days being sure there were no air pockets. Blew the water out by mouth, stuck them in a couple cases and they fired fine.

 

[T-shooter]

Maybe you can use desiccant packs in power to absorb the moisture. May help, couldn't hurt.

 

[Bc'z]

http://bulletin.accurateshooter.com/2020/02/how-powder-moisture-content-affects-pressure-and-speed/
I’ve often wondered about the effect of humidity and powder performance. Maybe I missed it in the article, but during the before and after tests was the powder measured by weight or volume? Seems obvious that water “saturated” powder weighs more. If this is the case then wouldn’t measuring by weight result in more actual gunpowder being present in the dried powder test lot? And the next question is - does moisture content actually affect powder performance?

Questions
How much weight difference between dry and wet charge?
If your loading, shooting and tuning through the seasons dose it matter the amount of moisture content in the powder?
Wouldn't ambient humidity have more of an effect on performance due to air density?

Sorry to answer questions with more questions.
B

 

[ACF]

When you "dry" the powder, how do you know that the weight loss wasn't comprised of trapped solvent from the manufacturing process?????

Chris

 

[The boogalorian]

Is it safe to assume that the powder is unaffected until the container is opened for the first time?

 

[243winxb]

From link

The powder charge and bullet were of course the same in both sets of cartridges.)

If same powder charge by weight, dry powder would increase pressure and velocity. Dry powder= more powder.

But link doesnt make it clear.

Some powders are made using water. Then dried. http://www.firearmsid.com/Feature Articles/McCord_gunpowder/

I have checked 3 different powders, old vs new, different lots. The new lot by volume has been heavier so far.

I feel powder gets lighter over time, after opening. More testing needed.

Military test show and Hodgdon will tell us to work up a new loading when changing lot numbers of the same powder.