Comments on: Tech Tip: Changes in Humidity Can Alter Powder Burn Rates

By: Jay Cutright

Jay Cutright — Wed, 28 Oct 2015 01:45:57 +0000

So what is the best temperature and humidity to keep my powder storage room at to keep the burn rate like it is supposed to be?

By: Guy

Guy — Tue, 27 Oct 2015 22:32:55 +0000

Not knowing the velocity change makes it hard to tell if its a issue or not. I known if you leave the powder out on the scale overnight its not unusual to see a different weight the next day. As they weigh the powder it could more of a difference in weight then burn rate. Just to muddy the situation lol.

By: Thomas

Thomas — Tue, 27 Oct 2015 17:53:33 +0000

Time/exposure/effect is presented via graphs in the book, if I recall correctly.

By: bdale

bdale — Tue, 27 Oct 2015 15:08:47 +0000

If the caps are left on tightly how does it change in moisture content

By: David Lawson

David Lawson — Tue, 27 Oct 2015 05:44:56 +0000

I worked in the chemical industry for over twenty years and was aware of this problem.
As such I have always bought half a kilo at a time and always store in the same spot in a cupboard.

By: Dan W

Dan W — Tue, 27 Oct 2015 00:15:41 +0000

Another question. Lets say a powder starts life from the manufacturer at 10% RH. If that powder is left open and comes up to 50% RH for a time period. This powder then is dried out back down to 10% RH like when it was made. Will it have the same burn rate as it did when it left the factory or is there a humidity/time degradation?

-Dan

By: Bryan Litz

Bryan Litz — Mon, 26 Oct 2015 22:59:45 +0000

This is a VERY interesting and valuable article. I’ve always wondered about this very thing. I’m happy to read this article sourced from a credible ballistician from Norma. We were just speculating about this in the pits today. One further question I have (if Johannson could be called on again); how long does the powder have to be exposed to a different humidity environment to have it’s burn rate affected by humidity? Typically, competition shooters go thru one or two 8 lb jugs of powder a year. Could the 2-3 months (or so) from the time a keg is ‘cracked’ until it’s gone affect it’s burn rate if stored in a different humidity environment; or does it take years for powder to absorb or expel moisture?

Thanks again for a very informative article!

-Bryan