Article on the effects of moisture content of powder- Aug. PS

I read it. It was very good article. I was told by Ron Reiber at Hodgdon that moisture was a factor is velocity and accuracy.
It explained the reasons pretty well. Here in the northeast it does make sense to know just how much it effects the given loads. It was worth reading.
 
I agree with Gerry. Here in Maine it is not unusual to have over 60% humidity in my reloading area during the wet seasons (April -July & Oct - Dec ), then down to 10% during the winter. The article was very enlightening and well worth reading.

Dick
 
Good question, as well as where did it start at the beginning of the match? I think that the article represents some excellent work that leads to a whole bunch of questions, that are as yet unanswered. IMO it presented some new information that I thought might set some wheels to turning.
Boyd
 
Moisture in air and the powder measure is not air tight. Amount of time the powder is exposed to the air.
 
Not really. I'm sure it was tested at hodgdon. I won't doubt there testing facilitys.
The article agreed to the information i had received at Hodgdon
 
The energy density of gunpowder is about 4 megajoules per kilogram. The heat of vaporization of water is about 2.3 megajoules per kilogram. These numbers are close, scientifically speaking. Thus it only makes sense that adding water to gunpowder has an effect on muzzle velocity. Energy spent in vaporizing the water cannot be utilized to accelerate the bullet. Dry firewood burns hotter than wet firewood. Nice article. Wish PS had more of these.

Cheers,
Keith
 
Why did our fighters in WWII use water injection when they had an enemy on their backsides?
Why did a KC 135 use water injection to get off the ground with max fuel load?
I'm not educated in physics but I'm wondering if not all is lost when the water changes states.
Larry
 
llboers said:
Why did our fighters in WWII use water injection when they had an enemy on their backsides?
Why did a KC 135 use water injection to get off the ground with max fuel load?
I'm not educated in physics but I'm wondering if not all is lost when the water changes states.
Larry
Click to expand...
Larry the use of Water Injection was to eliminate Detonation in the combustion chamber during WIDE OPEN THROTTLE situations.

Clarence
 
The Norma reloading manual has lots of data on the moisture content of their powders complete with test data.

It is well worth the money for this alone.

Glenn
 
Good article; very interesting. However, I think there are many parts to the equation and when looking at moisture content you have to look at the material make-up and its properties in relation to the whole.

Ken
 
It is not so much that the article provides "Do this, and your groups will get smaller." directions, but that it is thought provoking, and points out that the magnitude of the velocity differences between different moisture contents is significant, and probably more than anyone would have imagined.

Some time back, Jim Borden told me of preloading for a big match, in batches, over a period of time in which the humidity took some extreme swings. At the beginning of each loading session, he established what weight, would produce the desired velocity. The extreme spread of these charge weights, from batch to batch, which all produced the same velocity, was 1.5 gr. When he shot test groups with ammunition that was pulled from all the lots, it grouped well. Food fro thought....

At Visalia, during matches that take place in hot weather, there is a considerable temperature and humidity change through the day, so not only are velocities impacted by a significant increase in temperature, but there may be some contribution to velocity change from powder drying in the measure, and if, as Jim, and others contend, tune is velocity specific....I say may, because that test has yet to be run. As I said, food for thought.
 
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