Gunpowder or scale?

rcairflr

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Jul 7, 2013
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134
OK, so the results are in:
After 3 days of 50.05 grains of H335 powder being left open in the garage with a relative humidity of about 50%:

It still weighs 50.05 grains. There was no loss or gain in weight.


I initially suspected a problem with the scale and that is what I still suspect.
 

dkhunt14

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Dec 14, 2008
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462
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selinsgrove pa.
Well I have a Denver TR603D and I calibrate it often. I even set a small RCBS weight on every time I use it just to check it. I even have that weight written in grains on the scale. My charge got heavier over night. In 9 years it was never off. If the humidity when you set the powder in the garage was the same as the powder it wouldn't have changed. Humidity here depending on time of year can be real high or low. Other shooters have also told me that they have seen changes in weight after sitting. Just don't do what the one guy did. Don't try to dry it in the Microwave. His wife wasn't very happy and even though she wasn't home at the time and the fact that he cleaned it up and bought a new microwave, she still knew. Matt
 

Bill Johnson

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Sep 27, 2014
Messages
102
OK, so the results are in:
After 3 days of 50.05 grains of H335 powder being left open in the garage with a relative humidity of about 50%:

It still weighs 50.05 grains. There was no loss or gain in weight.


I initially suspected a problem with the scale and that is what I still suspect.

I suspect your scale is just fine. They don't change with atmospheric conditions whereas powders can and do.
 

nfhjr62

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Apr 17, 2008
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404
Location
Philadelphia Pa.
Did something a little different, left some IMR 4895 in my Lyman scale fore a week, seven days loaded twenty five rounds for my 30/06 match rifle and held the ten ring at 600 yrds. so was there any proplems with the powder.
 

gohring3006

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Mar 17, 2014
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Ohio
Did something a little different, left some IMR 4895 in my Lyman scale fore a week, seven days loaded twenty five rounds for my 30/06 match rifle and held the ten ring at 600 yrds. so was there any proplems with the powder.

This is what I was wondering. I would like to see if there is a velocity change or pressure.....
 

Bill Johnson

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Sep 27, 2014
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102
I've thought about this on more than a few occasions as I spent many years in Florida reloading in the garage. The powder manufacturers have quite an allowable range of moisture content to their powders. This directly affects powder density. But I would think it would not affect the total energy of the charge so that if the moisture content is not so high as to cause degradation of the powder, I suspect the only affect it would have upon ignition is to slow and cool the process slightly. This is all conjecture on my part.

I'd have to go back and look at some old notes but I recall leaving cases charged and open to the atmosphere for 3 days had no appreciable affect on performance, but that was back when the only rifle I had was a 30-30 and a sporterized Springfield. I do know, though, that varying density changes load density which can affect performance but normally will not be seen unless shooting longer ranges, say over 300 yds.

I think the take-away is that powder does gain and lose moisture but should not be an issue to the normal handloader. In the OP's case, leaving the original charges as initially thrown was the right thing to do. What was lost overnight was probably moisture which was replaced with powder.

One last point: We typically read humidity as "relative" which is a ratio of current air moisture content to the maximum it can hold at that temperature. Even if relative humidity is constant over a 24 hour period, absolute, or how much moisture is actually in the air, constantly varies with temp.

I'm a pragmatist, not a scientist so hopefully some of the more learned here will chime in.
 

fmajor

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Oct 8, 2009
Messages
552
Location
USA
I've thought about this on more than a few occasions as I spent many years in Florida reloading in the garage. The powder manufacturers have quite an allowable range of moisture content to their powders. This directly affects powder density. But I would think it would not affect the total energy of the charge so that if the moisture content is not so high as to cause degradation of the powder, I suspect the only affect it would have upon ignition is to slow and cool the process slightly. This is all conjecture on my part.

I'd have to go back and look at some old notes but I recall leaving cases charged and open to the atmosphere for 3 days had no appreciable affect on performance, but that was back when the only rifle I had was a 30-30 and a sporterized Springfield. I do know, though, that varying density changes load density which can affect performance but normally will not be seen unless shooting longer ranges, say over 300 yds.

I think the take-away is that powder does gain and lose moisture but should not be an issue to the normal handloader. In the OP's case, leaving the original charges as initially thrown was the right thing to do. What was lost overnight was probably moisture which was replaced with powder.

One last point: We typically read humidity as "relative" which is a ratio of current air moisture content to the maximum it can hold at that temperature. Even if relative humidity is constant over a 24 hour period, absolute, or how much moisture is actually in the air, constantly varies with temp.

I'm a pragmatist, not a scientist so hopefully some of the more learned here will chime in.

So if there's an appreciable amount of change in the reactivity of a powder charge due to atmospheric conditions, to me the next question(s) would be

1) how long can loaded ammo remain unaffected by humidity/atmospheric conditions?
2) is it, then, prudent to somehow seal our loaded ammo?

Great discussion - tagged!
 

Bill Johnson

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Sep 27, 2014
Messages
102
So if there's an appreciable amount of change in the reactivity of a powder charge due to atmospheric conditions, to me the next question(s) would be

1) how long can loaded ammo remain unaffected by humidity/atmospheric conditions?
2) is it, then, prudent to somehow seal our loaded ammo?

Great discussion - tagged!

It's my experience that there is little change in reactivity, but that testing was very limited and some 30 years ago.
 

feelinducky

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Oct 6, 2010
Messages
408
Thanks for all the replies. My gut tells me there is some type of problem with the reproducibility with my scale. That is hard for me to understand because it is a simple beam scale. I need to just break down and get a new one.
 
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