On Humidity and Powder

[44MAG#1]

In reference to Unique Hotter post.

Just an insignificant test by insignificant me today on humidity and powder weight.
This morning I took a hopper of A2400 and did a little test.
I threw 10 charges in my scale pan twice. It weighed 140.0 grains.
I then took the powder and poured it into a paper plate and set it outside IN THE SUN.
At 10:30 AM the temp was 70 degrees with a humidity of 60 percent.
I checked it often and kept it stirred so all the powder would get the same treatment.
I left it for 4 hours. About half that time was in direct sun and half in the shade.
At 2:30 the temperature was 84 degrees and 40 percent humidity
I then put the powder back in the hopper and went through the same preparatory preparations as the first time I did the first 10 throws and this time ten throws weighed 139.1 grains.
The first ten before putting it outside at 140.0 grains averages 14.0 grains.
The second ten after being outside at 139.1 averaged 13.91 grains.
Now this is an insignificant test by a more than insignificant person.
While this proves nothing to those in the know. Please be gentle with me as you criticize me and my little test
Take it as you will.

[TD1886]

In reference to Unique Hotter post.

Just an insignificant test by insignificant me today on humidity and powder weight.
This morning I took a hopper of A2400 and did a little test.
I threw 10 charges in my scale pan twice. It weighed 140.0 grains.
I then took the powder and poured it into a paper plate and set it outside IN THE SUN.
At 10:30 AM the temp was 70 degrees with a humidity of 60 percent.
I checked it often and kept it stirred so all the powder would get the same treatment.
I left it for 4 hours. About half that time was in direct sun and half in the shade.
At 2:30 the temperature was 84 degrees and 40 percent humidity
I then put the powder back in the hopper and went through the same preparatory preparations as the first time I did the first 10 throws and this time ten throws weighed 139.1 grains.
The first ten before putting it outside at 140.0 grains averages 14.0 grains.
The second ten after being outside at 139.1 averaged 13.91 grains.
Now this is an insignificant test by a more than insignificant person.
While this proves nothing to those in the know. Please be gentle with me as you criticize me and my little test
Take it as you will.

Well you proved that the powder weighs less the drier it is.

[44MAG#1]

Well you proved that the powder weighs less the drier it is.

Did we have any doubt?

[Recycled bullet]

If the powder was left in the sun for a week, then how much would be the change in density?

[44MAG#1]

If the powder was left in the sun for a week, then how much would be the change in density?

Don't know. I will leave that up to some other experimenter that is more significant than me.
More than likely not as much as if it were left in the sun for 2 weeks.

[john.k]

I bought a big jug of powder ,and the blow mould jug was imperfect around the screw thread .....powder could spill ,and air certainly get in.........I rang the makers (ADI) mainly to give them a heads up on the container fail.............anyhoo,big drama ,return the whole lot ,dont use it etc ..........however ,there was no mention of any replacement ,or maybe a truckload of free samples ......so I just kept it and used it all up.

[charlie b]

This does bring up an interesting test that could be done.

Moisture level in the loaded cartridge vs velocity. You'd need a good way to measure humidity and the cartridges would need to be sealed once loaded.

Control of humidity could be done with something like a humidor.

Determine the humidity level for your 'control'. Weigh the powder at that level and load some up. Then take some of those same loads and put in high humidity. Let stabilize, weigh again (they should weigh a bit more now) and load. Another batch should be weighed after being in the high humidity and then loaded. To be a more precise test all of this should be done at a fairly constant temperature. About ten loads of each should be sufficient to see the effect, if any.

So you have three batches. One, control humidity level. Two, weighed at control level and 'soaked'. Three, weighed at 'soaked' level.

Could also do this with two different charges, one with a fairly low load density and one with a fairly high load density.

Test engineering is fun stuff!!!

[no, I won't be doing this ]

PS shooting should all be done at a constant temp, not one batch in the morning and another in the afternoon. Box of ammo should not be in direct sunlight, etc, etc. And, yes, the temp of the gun/barrel/chamber should be controlled and/or monitored.

[44MAG#1]

This does bring up an interesting test that could be done.

Moisture level in the loaded cartridge vs velocity. You'd need a good way to measure humidity and the cartridges would need to be sealed once loaded.

Control of humidity could be done with something like a humidor.

Determine the humidity level for your 'control'. Weigh the powder at that level and load some up. Then take some of those same loads and put in high humidity. Let stabilize, weigh again (they should weigh a bit more now) and load. Another batch should be weighed after being in the high humidity and then loaded. To be a more precise test all of this should be done at a fairly constant temperature. About ten loads of each should be sufficient to see the effect, if any.

Could also do this with two different charges, one with a fairly low load density and one with a fairly high load density.

Test engineering is fun stuff!!!

[no, I won't be doing this ]

I won't be doing it either.
I am 70. And they won't be anything done or tested that will ever be good enough for some.
Just like chronographing loads and posting that result/results.

[MostlyLeverGuns]

Long, long ago, Elmer Keith discussed powder changing due to humidity. He advised that after developing a load and setting the volumetric measure, that VOLUME should be used, rather than weight for further loading of that powder/bullet/primer/case combination.

[Bent Ramrod]

There are residual solvents (diethyl ether and acetone) that remain in smokeless powders even after they are extruded and cut. The nitrocellulose forms a colloid in these solvents that starts as a thick soup and goes through a gel-like state to a moldable plastic as most of the solvents are removed and recovered in the manufacturing process.

You can smell this sometimes when you open a new can. The smell gradually goes away the longer the powder is kept, but as evaporation comes from surfaces, there is still a little incorporated into the interior of the granules. Probably your sun exposure just brought more solvent residue to the surface and evaporated it, reducing the weight.

If you leave it long enough in the sun, or in a hot environment, the nitrate groups on the nitrocellulose start to decompose. If enough of this decomposition happens, the stabilizers are overwhelmed and the acidic byproducts start decomposing the powder, giving off more gases and acidic residues, and further reducing the weight.

[Larry Gibson]

This does bring up an interesting test that could be done.

Moisture level in the loaded cartridge vs velocity. You'd need a good way to measure humidity and the cartridges would need to be sealed once loaded.

Control of humidity could be done with something like a humidor.

Determine the humidity level for your 'control'. Weigh the powder at that level and load some up. Then take some of those same loads and put in high humidity. Let stabilize, weigh again (they should weigh a bit more now) and load. Another batch should be weighed after being in the high humidity and then loaded. To be a more precise test all of this should be done at a fairly constant temperature. About ten loads of each should be sufficient to see the effect, if any.

So you have three batches. One, control humidity level. Two, weighed at control level and 'soaked'. Three, weighed at 'soaked' level.

Could also do this with two different charges, one with a fairly low load density and one with a fairly high load density.

Test engineering is fun stuff!!!

[no, I won't be doing this ]

PS shooting should all be done at a constant temp, not one batch in the morning and another in the afternoon. Box of ammo should not be in direct sunlight, etc, etc. And, yes, the temp of the gun/barrel/chamber should be controlled and/or monitored.

If we read this article we find Bryan Litz conducted a very similar experiment.

https://chronoplotter.com/2021/08/19...-affect-powder

Granted, not with Unique but with a much slower brining extruded powder. He does show the velocity and pressure differences. A similar experiment could be done using Unique.

[44MAG#1]

Long, long ago, Elmer Keith discussed powder changing due to humidity. He advised that after developing a load and setting the volumetric measure, that VOLUME should be used, rather than weight for further loading of that powder/bullet/primer/case combination.

I would think that the chemical composition of powder would have been improved since Keith wrote that.
Who knows though? Maybe not.

[44MAG#1]

There are residual solvents (diethyl ether and acetone) that remain in smokeless powders even after they are extruded and cut. The nitrocellulose forms a colloid in these solvents that starts as a thick soup and goes through a gel-like state to a moldable plastic as most of the solvents are removed and recovered in the manufacturing process.

You can smell this sometimes when you open a new can. The smell gradually goes away the longer the powder is kept, but as evaporation comes from surfaces, there is still a little incorporated into the interior of the granules. Probably your sun exposure just brought more solvent residue to the surface and evaporated it, reducing the weight.

If you leave it long enough in the sun, or in a hot environment, the nitrate groups on the nitrocellulose start to decompose. If enough of this decomposition happens, the stabilizers are overwhelmed and the acidic byproducts start decomposing the powder, giving off more gases and acidic residues, and further reducing the weight.

I am still going to use the powder I used.

[charlie b]

If we read this article we find Bryan Litz conducted a very similar experiment.

https://chronoplotter.com/2021/08/19...-affect-powder

Granted, not with Unique but with a much slower brining extruded powder. He does show the velocity and pressure differences. A similar experiment could be done using Unique.

Now that's my kind of testing

[44MAG#1]

Now that's my kind of testing

I wish I had the get up and go that some have.
My get up and go has done got up and gone.
Glad there are some that do test in a through and well thought out way.
Thanks to all of them for doing such a great job.

[Larry Gibson]

What are we to do about humidity in powder?

Good question, but in reality 99.99% of shooters are going to be able or want to do anything about it. As long as the loads we use are at or below SAAMI standards [as are most max loads in current manuals these days] a change in humidity will not have enough effect to be dangerous to firearm or person. The difference will be found in "discrepancies" in chronographed results test to test and perhaps a change of zero or accuracy. Enough to cause a discussion but, in reality, of little concern to the vast majority of reloaders.

[TD1886]

44Mag#1, we will have to start calling you WeatherMag#1!! LOL just kidding you. This humidity thing has been going on since we invented powder. Hey, remember the old say "keep your powder dry"? On a more serious not I was always amazed that a glass jar didn't keep powdered anything as dry as metal containers. I mean just how does moisture get through the glass? Or in reality is it the moisture that already is in the powder escapes and we see it on the inside of the glass?

[44MAG#1]

44Mag#1, we will have to start calling you WeatherMag#1!! LOL just kidding you. This humidity thing has been going on since we invented powder. Hey, remember the old say "keep your powder dry"? On a more serious not I was always amazed that a glass jar didn't keep powdered anything as dry as metal containers. I mean just how does moisture get through the glass? Or in reality is it the moisture that already is in the powder escapes and we see it on the inside of the glass?

Well, let's not worry about it.
Just another bump in the road of reloading on top of many, many , many , many ,many other bumps and pot holes etc. etc. etc. etc there is on the journey
Mountains out of mole hills. Straining at a gnat and swallowing a camel thing.

[Tim357]

Long, long ago, Elmer Keith discussed powder changing due to humidity. He advised that after developing a load and setting the volumetric measure, that VOLUME should be used, rather than weight for further loading of that powder/bullet/primer/case combination.

This. This right here.

[44MAG#1]

This. This right here.

I am not going to buy 4
or 5 powder measures.