Discussion in 'Blackpowder' started by Tallbald, Feb 11, 2015.
In the end though it is the WEIGHT that would matter if you were trying to get the last little bit out of your gun. Which is why serious match black powder cartridge and MLAIC competitors do not measure their powder by volume. They weigh out each and every charge.
It's really no different from smokeless loading. Benchrest shooters and others serious about accuracy weigh EVERY charge to something more accurate than a tenth of a grain. The rest of us find a Lee dipper or set a powder measure to supply a volume that is close enough to the desired weight and live with the slight variation that goes with using a volume measure.
Volume cc: 6.67
Volume grains: 100
Goex FFG: 104.6
Jim Shockey Gold: 88.3
Hodgen Tripple Seven: 77.2
Pyrodex P: 76.0
By looking at 100 grains it is easily converted to percentage. I weigh all of my black powder charges to get the best consistent accuracy. Thanks for the response.
Nobody establishes the accuracy of their equipment, which, after all, is of utmost importance. Was the volume measure used to create the Cutrich.com conversion chart accurate to 4 decimal places as suggested by his data? We don't even know if it was accurate to 2 places; he doesn't provide any error data for any of his measurements, volume or weight.
The only reason for measuring charges, using either volume or weight as a metric, is to ensure consistency. Comparing your measurements with other people's data is essentially nonsense unless you know your equipment and theirs produce the same errors.
Must be wintertime. Somebody throw another log on the fire. And while you're up....
There IS NO SUCH THING as volumetric grains. Grains is a measure of weight, not volume. The volume equivalent is just something that black powder folks made up and use as a convenient way to measure our powder out in the field.
So right off the first line where it says 100 gns of Goex FFFg weighs 101.1gns is wrong. By definition 100gns/weight of black powder is 100gns/volume.
Now what he SHOULD have done is measured the volume in CC's for 100gns of each of the popular brands of black powder to arrive at an average which would then be used to equate to 100gns/volume. That would be something useful.
Again there is no recognition in science or engineering of any sort of volumetric measure called "grains". So it's clearly something we BP'ers made up way back in the past. It's simply not a standard of any sort other than the link to being the volume for100gns/weight of black powder.
The fact that the volume for 100gns/weight of the different brands and grades varies a little is something that the old timers apparently glossed over. Or they would use different 100gn/volume measures as required to drop 100gns/weight for various brands or grades as they came to use them.
The Hogdon 25th Edition reloading manual lists Pyrodex equivalent to BP counterparts by weight. It also lists load data for Pyrodex in cartridges. This is before 777, but I would suspect that new Hogdon load data manual would have less confusing cartridge load data like the old one.
The grain is from the avoirdupois system of weights and measurements that was a British system from before Henry the VIII's time, and is used in US still today. It's one of the smallest measurements in our system. (grains, ounces, pounds, tons and etc). (Not Metric)
The “grain” also happens to be the same in avoirdupois, troy, and apothecaries UNITS OF MASS.
The measures we use for our powder are volume measures. Period!! They can be used to measure the volume of anything you might put in them. The Words (Powder Measure) are used to sell the measure to a specific croud. All of you. But the measure itself has nothing at all to do with the weight of Black Powder.
These volume measures we use for our powder are used and marked the same way that our cup and oz's are.
1 cup = 8 oz. or 3500 grains.
Now it doesn't take to much to realize that 1 cup of feathers won't weigh 8 oz. Or 1 cup of lead won't weigh 8 0z. But they will both ocupy the same space.
The same thing goes for our powder measure. I could set it at 100 grains and fill it with ground feathers or lead bb's and neither will even come close to 100 grains because both have greatly different densities. But again they will both ocupy the same space.
So being a person can put things of different densitys such as above in the measures, What standard was used to make them? For sure it wasn't lead or feathers, or gun powder for it all has different densities as well.
WATER!! It is the only substance in the world that always has the same density since the beginning of time and anywhere in the world.
The weight of distilled water at the temperature of 62 Fahrenheit the barometer being at thirty inches Is the standard used by the world. This includes US and metric measurements.
To make a 1 cup measure you would weigh out 8 oz. distilled water or 3500 grains if you like then make your container hold that amount. Mark the measure 8 oz. or 1 cup
To make a 100 grain powder measure weigh out 100 grains of distilled water and make your measure hold that amount. Mark the measure 100 gr.
The measure above was made for our system but it could be made with metric marks on them too. water weighed the same but metric weights. milligram, drams or cc if you like.
distilled water weight is also used to make Our gallon and all our other weights and measurements. Even our bushell.
This water standard makes all volume measures to be the same anywhere in the world.
The reason we use a volume measure for black powder is that it is the only way to compare powders performance between brands or even lots from the same brand. Velocities, fowling, pressures and etc.
It is also the only way to acurately write down or tell someone how much powder a certian case will take to seat the bullet properly. If we used weights every brand of powder might sit at different heights in the case because of density, moisture content or ingredients used to make it. It would also be useless to compare different powders by a certian weight.
Someone here posted the advertised weight of a cartridge powder from way back. And said there was now way to get that amount in a modern case. But that weight was only for that specific powder at that time. Powder company's have always experimented with densities, moisture content and even ingredients so there would be no way to compare then to now. If those company's would have printed volume instead of grain weight on their box we would be able to compare.
(The “grain” is the same in avoirdupois, troy, and apothecaries units of mass.)
1 grain = 1/7,000 pound = 1/437.5 ounce
1 dram = 1/256 pound = 1/16 ounce
16 drams = 1 ounce or 437½ grains
1 milligram = 0.015 grain
1 grain = 64.798 91 milligrams (exactly)
1 ounce, avoirdupois = 437.5 grains (exactly)
1 gram = 15.432 grains or 0.035 ounce, avoirdupois
1 pound, avoirdupois = 7000 grains (exactly) or 453.59237 grams (exactly) or 256 drams or 16 oz.
A quick simple google search found these.....
What you posted implies that there is such a thing as an official volumetric measure for "grains". But this just doesn't pan out when we go looking around to find such a thing.
I see cases in these papers where water is being weighed in grains. But they are all being used to weigh a mass of water which is then used to determine other measures or values. I may have missed something but no where to I see anything that suggests that volumes listed in grains are used for anything directly.
The old dead guys at the factory used a scale to weigh the powder charges...
Sharps spent a page in their 1875 catalog detailing how to use an apothecary scale and translate apothecaries into grains weight...
It started as grains of wheat but was found to be inaccurate and changed to water weight. It's to much for me to explain so read this carefully. you will have to scroll up a page or so from the opening page to start from the beginning.
So that leaves us with the idea that the measures are sized to nominally deliver the stated weight of black powder and that it has nothing to do with water.
All conventional powder measures from the brass tubes used for black powder to an RCBS smokeless powder measure use volume as a representation of weight. In modern smokeless application, one calibrates the volume to ensure it consistently throws the same weight, but it is measured by volume. With black powder, the assumption is that there is sufficient uniformity of granulation and and insufficient difference in power between brands that a nominal volume will work for all. That the volume is based originally on weight must be understood but then may be regarded as surplus knowledge to need, unless one is of the opinion that exact uniformity of charge is required for each shot, as in BPCR competition, in which case, weighing is to be preferred to a less accurate volumetric representation of weight. The bickering over whether one should use volume or weight is unnecessarily Jesuitical. One is using weight in either case so the choice is between approximation (volumetric measures of black powder) or precision (weighing). For most applications, a volumetric representation of weight will produce sufficient uniformity of charge. If insufficient for one's purpose or taste, by all means, weigh.
This falls down for substitutes like T7 which are more uniformly grained, smaller grained and, thus, packs more densely. The .85 x BP charge accounts for the fact that a greater weight of T7 per given volume is achieved than for black powder.
In any event, hardly a matter for heated partisanship.
The issue arises when some poor newcomer comes looking for guidance from some search link. If poor or wrong practices and beliefs are allowed to be stated in strong terms with no rebuttal then it leads some poor guy into similar mistakes.
I'm often proven wrong and that's fine. I know enough to know that I'll never know it all. And that recognized mistakes are a way of learning.
Yes, we poor uneducated black powder shooters use the word 'grain' to describe a volume measurement, something the world's governments do not endorse (which some folks would consider sufficient reason by itself). I suppose it will lead to complete ruin in the next couple hundred years (since it hasn't in the last couple hundred).
In the mean time,
with the possible exception of all the elements in the periodic table...
Not a big deal, but there's a ton of misunderstanding about it all.
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