Humidity absorpsion and powder

[fatelvis]

I pose this question to all of you that are better handloaders than I, and probably shoot at a higher level as well! Lol :
To achieve the most consistent moisture content in your stored powder (over 1-2 years) as you use it, which would be a better practice?
1) Buy an 8lb jug and reseal it tightly after use and shake it thoroughly before each use.
Or...
2) Buy eight 1# cans of the same lot, and use one at a time, leaving the remaining pounds sealed until they're needed.
Or another option?
As always, Thanks!

 

[NorCalMikie]

Buy what you need "at the time", use it up then buy more as needed. I have 10 to 15 year old powder that is still good. Cap goes back on TIGHT. No extra humidity to deal in my area like some other places.

 

[JMayo]

I store inside. I go for price value of 8lbs. It last 1.5 yrs + - .

 

[Dusty Stevens]

Powder does not aBsorb moisture but it does aDsorb moisture so itll change as the humidity does as soon as you open it. So it does not accumulate over time it does change. Dont let it concern you just do whats best for you. I vote 1lb jugs unless you use 8lb in a year

 

[fatelvis]

Powder does not aBsorb moisture but it does aDsorb moisture so itll change as the humidity does as soon as you open it. So it does not accumulate over time it does change. Dont let it concern you just do whats best for you. I vote 1lb jugs unless you use 8lb in a year

I never knew adsorption was a word. I learn things all the time from this site! Thanks

 

[Dusty Stevens]

Think of a towel or a car with water on it. The towel absorbs but the car only adsorbs it on the surface. May be better examples

 

[Webster]

I pose this question to all of you that are better handloaders than I, and probably shoot at a higher level as well! Lol :
To achieve the most consistent moisture content in your stored powder (over 1-2 years) as you use it, which would be a better practice?
1) Buy an 8lb jug and reseal it tightly after use and shake it thoroughly before each use.
Or...
2) Buy eight 1# cans of the same lot, and use one at a time, leaving the remaining pounds sealed until they're needed.
Or another option?
As always, Thanks!

Take about 50 gr of powder and weigh it on an accurate scale. Then put it out in the bright sun on aluminum foil for about an hour and reweigh it. A 1% change is about .5 grains. An article I read said pelletized military nitro cellulose can hold 1-3% moisture under high humidity conditions.. This will give you some idea of whats going on. If you try it let us know the results.

 

[jds holler]

This is precisely the question that makes me wonder if exact charge weight is as important as exact charge volume. jd

 

[dogdude]

1 pd, you can sell 1 pounders easier than 6.5 out of an 8 lb jug.

 

[fatelvis]

This is precisely the question that makes me wonder if exact charge weight is as important as exact charge volume. jd

I’ve also considered the weighing/throwing subject, and which is better for consistency because of the absorption. Am I correct assuming bench rest guys throw their charges? Is this why?

 

[Dusty Stevens]

I’ve also considered the weighing/throwing subject, and which is better for consistency because of the absorption. Am I correct assuming bench rest guys throw their charges? Is this why?

Thats one reason we do. Main thing is speed

 

[ClassCat]

Thats one reason we do. Main thing is speed

Dusty is correct with throwing chargers. If you have a system as i do an RCBS charge master is fast enough to load 12 rounds. Clean and prep 3 cases at a time,the charge master is constantly dropping charges while you are prepping cases and seating bullets. If you get an overthrow (+1/10) use it as a fouler or sighter

 

[Texas10]

This is precisely the question that makes me wonder if exact charge weight is as important as exact charge volume. jd

If the weight changes, why wouldn't the volume change too, in proportion to moisture absorbed? Water has to go somewhere, and it has physical mass.

 

[Dusty Stevens]

If the weight changes, why wouldn't the volume change too, in proportion to moisture absorbed? Water has to go somewhere, and it has physical mass.

Yes. Makes the powder fluffier for a better word. Takes up more space

 

[BoydAllen]

Yes. Makes the powder fluffier for a better word. Takes up more space

Have you seen the excellent article on this subject that was published in PS? IMO it is the best info that is available.

 

[Dusty Stevens]

Have you seen the excellent article on this subject that was published in PS? IMO it is the best info that is available.

no I havent. can you forward me an electronic copy if you have it easily accessable?

 

[BoydAllen]

no I havent. can you forward me an electronic copy if you have it easily accessable?

Check your PMs

 

[muleman69]

8 pounders are a bit unhandy but all the factors should remain the same over time.

 

[Webster]

I’ve also considered the weighing/throwing subject, and which is better for consistency because of the absorption. Am I correct assuming bench rest guys throw their charges? Is this why?

Many ranges just don't have facilities to plug in a 100 scales. At the Super Shoot I see a lot of guys throwing charges then checking them on a small scale like my $50 Hornaday scale. Apparently it works for short range 100 & 200 yard comp. Some guys are reloading under a canopy on a grassy area. With experience they are probably +/- .1 grain. As far as absorption/adsorption maybe the powder stabilizes at some % moisture then it cannot absorb more. Would this make all powder the same? Eventually I will weigh some powder dry it and reweigh.

 

[fatelvis]

Now that I’ve been playing with my chronograph more, I’ve noticed big differences in velocity with older and brand new samples of the same powder. I think the old problem of changing lots of powder might have more to do with the humidity content (old vs. new powder) more than a different lot number from the factory.