Density of black powder compared to water?

[Darto]

I have read it is about 85%.

Take this chart:
http://kwk.us/cases.html

Shows brass cartridge cases and the amount of water in grains of weight that each will hold.

Is it reasonable to say that the grains of weight of black powder filling those same cases would run about 85% of the listed values for water?

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REFERENCE:

Here is where I got the 85% number...
Here: http://www.thehighroad.org/archive/index.php/t-273817.html


In this long thread two guys wrote something that I kind of interpret as BP weighs about 85% of water, volume for volume. They wrote:

" Basically, the grains by volume measurement stems from an era when people did not have access to scales and, needed an easy way to measure powder in the field. It was derived by finding the volume of, say, 100 grains of water and then using that same volume of powder and calling it 100 grains by volume.

What you end up with is a sort of bulk measurement using specific gravity (bulk specific gravity). Most people equate specific gravity with density, but that is only a happy coincidence. Specific gravity is the weight of a substance compared with the weight of an equal volume of water. It just happens that density comes close, sometimes.

The volume grain is best likened (as before) to a convenience measurement. It was conceived in a day when one could not actually weigh charges out. Can you imagine trying to weigh 65 grains of musket powder in the heat of battle? What one does is to weigh out the needed number of powder grains by weighing out the same number of grains of water and then using the same volume of powder as the water, and that is all there is to it. It is best described as using the bulk specific gravity as a measuring tool. It is simpler to do than to write about.

Once you have derived the number, it probably will be consistent for that lot of powder, but the next time you buy powder, it will probably change a little. I use 0.85 as a practical approximation, and it only really makes a big difference if one is shooting a large volume of powder. However, even 17 grains of FFFg, a load for my 1862 Police, measured by weight, approximates 20 grains by volume, which
is still just fine. "

 

[coloradoclyde]

The volume grain is best likened (as before) to a convenience measurement. It was conceived in a day when one could not actually weigh charges out. Can you imagine trying to weigh 65 grains of musket powder in the heat of battle? What one does is to weigh out the needed number of powder grains by weighing out the same number of grains of water and then using the same volume of powder as the water, and that is all there is to it. It is best described as using the bulk specific gravity as a measuring tool. It is simpler to do than to write about.

:shocked2: ..You lost me!....
If one has the ability to weigh water.....one has the ability to weigh powder....

 

[George]

Equal volumes of water and powder weigh the same. If you make a fixed measure to hold a certain weight of water, it will hold exactly that same weight of powder. I've checked this more than once with my digital scale, and it holds true for 3F and 2F, at least.

Spence

 

[necchi]

Darto, your comparing apples and oranges,, modern CF volume charts and 150yr old powder discrepancies.
But they both have to do with powder right?
Don't over think it.
Modern black powder making is much more consistent and CF folks are looking for tiny variations in cartridges to get that last point or two in a bench match.

 

[AZbpBurner]

Equal volumes of water and powder weigh the same. If you make a fixed measure to hold a certain weight of water, it will hold exactly that same weight of powder. I've checked this more than once with my digital scale, and it holds true for 3F and 2F, at least.

Spence

I was skeptical, so I tried it for myself. I found that 2 ml H20 weighed 30.1 Gr. and 2 ml Goex 3F BP weighs 29.0 Gr.

Close enough for me :thumbsup: . I didn't to any multiple sample averages - just one each sample in pre weighed 2 ml centrafuge tubes.

 

[TNGhost]

"Is it reasonable to say that the grains of weight of black powder filling those same cases would run about 85% of the listed values for water?"

That would depend on the preparation of the powder. You kinda answered your own question, when you mentioned lot to lot, maker to maker differences. Moisture content, geometry(grain size) and even recipe component percentage(though not terribly significant) all have a bearing. Is it enough difference to make any practical difference? I guess that depends on the original purpose that gave rise to your question.

As far as the case water weight/volume, it is no more than a convenient reference for the comparison of case volumes in cartridge guns. Loaders/reloaders use it to get an idea of the properties of different loadings, from case to case.

For instance the chart you reference shows 5.6x50R and .219 Zipper to both hold 34 grains of water, so you would expect them to behave ballistically similar with the same powder load, all else being equal. It is a little more complicated than that, case design, chamber, etc. are going to have a bearing, which is why it is just a reference point. You'll notice even the "hyphenated"(ie. 45-70) black powder cartridges vary from their standard loading, when it comes to grains of water weight. Some more some less, even when projectile seating depth is taken into account.

In muzzleloading it was/is a "close enough" volumetric measuring device, that could be used anywhere, with any available black powder and be close enough. Hence a reference point here as well.

Its not so much an aspect of not having a scale, as it is having a reference point that was suitable for loading in the field, with what was available. In the case of muzzleloading, that it was such a good reference point, is the reason that black powder loads, to this day, are given volumetrically.

 

[tenngun]

Don't have a fine scale, but did find out years a go that one pint will hold a pound of powder. I stored some in old antifreeze gallon containers. Eight pounds in a one gallon container. About the same as water. Often old powder was sold by the pint.

 

[Patocazador]

Don't you have anything better to do with your time?

 

[ZUG]

How funny a comment :rotf: -- I like it :bow: . Much the same can be said as to a lot of the questions asked here at times :haha: .

 

[Golfswithwolves]

Don't have a fine scale, but did find out years a go that one pint will hold a pound of powder. I stored some in old antifreeze gallon containers. Eight pounds in a one gallon container. About the same as water. Often old powder was sold by the pint.

I've always heard about water that "A pint's a pound the world around." Seems to be the same with powder by Mr. tenngun's measure.