Volumetric equivalent standards for grain weight

[In Over My Head]

There was a very interesting thread recently regarding "drams equivalent" shotgun loads, trying to determine equivalency to so many drams of what granulation powder. (It seems to have been decided that is is equivalent to drams of FFg.)

Now I'm wondering if there is an accepted volume measure equivalent to "grains by volume".

In other words: Just supposing that "grains by volume" might also be based on FFg, is there a specific, modern measure of volume (ounces, Cubic inches, CCs, milliliters, etc.) in which we can express the volume of so many grains of FFg?

Practical purpose: If I were drilling a cavity in an antler tip, seeking to have a cavity of 40 "grains by volume" of powder, how can I determine the size of the cavity mathematically or with a known volume of some common substance besides black powder? It just seems strange using an explosive as measuring tool, especially when the corelation between the weight and the volume of any particular lot of FFg powder I might choose is probably highly variable to begin with.

In the Dixie catalog I see a list of the "grains volume" of common cartridge cases so that they can be used as measures, so I might back into a volume standard by measuring the volume of various cartridges I have around and comparing that to Dixie's chart. But I suspect that this method will give results that are even less exact than what are probably just convenient approximations in the first place.

 

[roundball]

The actual source reference might be in manuals like a Lyman BP Handbook, but I've read and accept that the standard is BP 2f...ie: 100grns volume measure of 2F real BP weighs 100grns weight.

I'll dig for a source tonight if I can remember it when I get home...know I read it in some credible source years ago...might have been in a Hodgdon reloading manual which had a section in it devoted to Pyrodex when it first came out...explained it's relationship to real BP, etc

 

[Zonie]

After checking a couple of reference books and hitting a dead end, I measured two different adjustable powder measures at 5 different settings and then calculated the volumes for each setting.

The results were were in close agreement which tells me that either the answer is the right one, or that the makers of these measures were using the same book for a powder volume value.

The answer I got for the average of all of the measurements was.

10 grains = .039 cubic inches.

Actually, the larger measure (the kind with the rotating funnel cap) agreed at each sitting that the volume for 10 grains was .040 cubic inches.

The smaller measure varied from .040 to .038 cu/in depending on the setting. It's variation brought the total average down to the .039 value.

Hope this helps.
zonie

 

[roundball]

The actual source reference might be in manuals like a Lyman BP Handbook, but I've read and accept that the standard is BP 2f...ie: 100grns volume measure of 2F real BP weighs 100grns weight.

I'll dig for a source tonight if I can remember it when I get home...know I read it in some credible source years ago...might have been in a Hodgdon reloading manual which had a section in it devoted to Pyrodex when it first came out...explained it's relationship to real BP, etc

Yes, it was Hodgdon's Load Data Manual #26...a whole section on Pyrodex RS as a BP 2F equivalent...has a chart of BP weights and the corresponding weights of Pyrodex RS (2F)...and the entire scale of BP from 10grns to 200grns in 10 grn increments, the weight matches the volume.

ie: 100grns volume measure of 2F BP weighs 100grns actual weight

[100grns volume measure of Pyrodex RS (2F) = 75grns weight]

 

[AJFedak]

I find this relationship interesting. But I was wondering how the 100 grains volume is taken. I know BPC shooters used drop tubes to settle the powder in their cases vs. just "dip'n pour". It seems there would different quantity of powder even though it is measured as 100 grs volume and therefore the weight would be different. But the philosophy there is just filling with as much black powder and still be able to seat the bullet.

 

[In Over My Head]

Thanks for the effort, Zonie! And you too, roundball.

So the hunch that "grains volume" coresponds at FFg was apparently a good one.

It seems practical to have a cubic equivalent to use while fiddling at the workbench rather than keeping a little pile of blackpowder on the bench as a measuring device. I will confirm volume with FFg weight for safety sake, but I like having a more practical volumetric value to work from initially.

Thanks!

 

[roundball]

"...I was wondering how the 100 grains volume is taken..."

My guess would be if/when it was officially established as a baseline reference, it would have been volume measured and weighed as precisely, consistently as possible, and it's has survived at least a couple centuries of opportunities to be challenged, proven incorrect, etc.

Fast forward, and it almost doesn't matter today...if I want to use a 100grn charge for example, and use a 100grn volume measure, and fill it the same way every time...even if my way ends up with only 95grns, or as much as 105grns, etc...as long as I do it the same way every time, "that's my 100grn charge" if you get my meaning...my rifle won't know it's only 95grns and so on.

 

[In Over My Head]

"if I want to use a 100grn charge for example, and use a 100grn volume measure, and fill it the same way every time...even if my way ends up with only 95grns, or as much as 105grns,"

Yes. But that brings us full circle to my original question: How big, in some quantifiable standard, IS a 100grn volume measure?

Right now it seems like a 100grn volume measure might be 0.4 cubic inches, but I wonder if the "industry" hasn't actually established this somewhere at some time. (If powder measure manufacturers can be said to represent an "industry". :hmm: )

 

[roundball]

Right now it seems like a 100grn volume measure might be 0.4 cubic inches, but I wonder if the "industry" hasn't actually established this somewhere at some time.

Fair question...seems like they would have driven that stake in the ground at some point in time...finding a credible source reference is usually the difficult part

 

[CoyoteJoe]

I think you are seeking a degree of precision which belies the use of any volume measure. It just is not a precise method. Fill your measure a dozen times, weighing each time and you likely will get a dozen different weights. Pouring and filling technique will likely cause more variation than the average difference between the densities of Fg, 2f,3f or 4f powders. Then too, when setting an adjustable measure one is likely to miss the mark by a grain or two. But it is really a moot point because a grain or two more or less will make no measurable difference in the accuracy of your rifle. As a starting point, why not choose a drill bit which matches the ID of your adjustable measure and drill to the same depth as your measure when set to the desired charge? It's going to be a "cut and try" process no matter what.

 

[In Over My Head]

Coyote Joe,

Thanks for the reply, but I think you are missing the point.

If I just repeat what I think I measure the volume of someones measure to be I am just heaping imprecision on top of imprecision. Like, if you worked in a bottle factory and had to make a new mold for one pint bottles, would you just find a pint bottle in the trash and try to duplicate the volume of that particular bottle or would you find out exactly what the cubic volume (Redundant, I know!) of a pint is supposed to be and work towards the established standard?

I'm not trying to measure charges to some new level of precision, but I am wondering if I were to carve a measure for a given volume of powder, what is the standard for that volume.

If I start by measuring the volume of another measure to the best of my ability (Which seems to be all I've found to go on, anyway!) Then I am heaping my measurement error on top of the previous manufacturing error and adding my own manufacturing error into my product.

Does that matter if I am just making a measure for my own use? Probably not. Does it matter if I attempt to carve a measure for you and represent it as being a measure of X grains volume? Yes, I think so.

It's like cutting a hundred studs for a new wall: Would there be a different result if I marked each cut with a tape measure before cutting as compared to just marking each new cut with the stud I had just cut? You knows there'd be a difference between the first and last stud if I wasn't measuring to a set standard (tape measure)! So, I seek a standard volumetric measure of "grains volume".

 

[Joel/Calgary]

I'm at work and don't have my reverences handy, and don't have time to do the calculations to check, but....

To come at this from another direction, I'm fairly sure I recall the Mad Monk mentioning, in a discussion powder densities, that most modern powder measures are calibrated for an aggregate density of 1.0g/cc, i.e. the same as water. This should be easy enough to check. If it is correct, then just convert the grains to grams (1gram = 15.43grains) and you have the volume in cc (or ml), or you can convert the grains to pounds or ounces and calculate the volume of that weight of water in cubic inches.

I also recall someone mentioning a common drill bit size that was useful for making powder measures because each 1/4" of hole gave 10gr capacity, but I cannot recall the bit size. Maybe someone else can, or can figure it out.

Back to work,
Joel

 

[paulvallandigham]

Claude: Don't make this any harder than it is. use a powder scale- the same one you have to measure smokeless powder-- and measure out the desired load on the scale. Then make your measure so it will hold that amount of powder, obviously by volume. Then, it doesn't matter if you are shooting 1Fg, 2Fg, 3Fg or whatever. The volume measure you make will contain that amount of powder when you use the same powder that you weighed. Change powder? Remeasure and make a new volume measure. If you buy an adjustable powder measure instead, weigh the volume of powder that you get from the scale on the particular measure. If the weighed charge is more or less than what you want, then make a note, or make a mark on the measure scale, and adjust the measure to that mark, and try again. If you are shooting small amounts of black powder in a small caliber revolver, or pistol, you need to be very careful about being consistent with the amount of powder actually thrown. Some shooter weigh each powder charge out and place the load in a tube to take to the range or field. The " Pre- measured charges " then are used to reload the gun. They tend to give a lot of consistency that you cannot get using a volume measure. And, on the opposite side of the scale, the guys with the huge, large caliber bench guns used in " slug gun competitions", will often weigh their powder charges-- very heft charges-- before going to the range, so they have the consistency they need to shoot small groups at obscene distances.

If weighing powder, and then making a volume measure works for most everyone else, it should work well for you, too. Because of a slightly related question asked on the forum last year, I took out my balance beam scale and measured several volume measures out of my adjustable powder measure on my scale to get an average, and then did the same thing using a large diameter " DIpper " measure I have for my fowler, and shotgun. I found the average powder charge to be much closer to actual weight, using my adjustable powder measure, than with the dipper measure. I tried it with both FFg and FFFg powder to see if using different granule sizes made any difference. There was a difference, but not enough to change the result. The setting on the dipper was more ' off " than the setting on the adjustable powder measure. Being larger in diameter, I had expected the dipper to throw the better charge, and that it would be more consistent. It wasn't. I spent another hour changing my pouring, and tapping techniques until I got tired of weighing powder charges and ended it all.

 

[In Over My Head]

Joel,

Converting:

1 c.c. = 15.43 "grains volume"
1 c.c. = .061023744 cubic inch
15.43 "grains volume" = .06123744 cubic inch
1 "grain volume" = .003955 cubic inch

That is right in there with what Zonie came up with!

I think this is a very workable conclusion for my purposes and I am pleased that this discussion has reached very close to the same answer through different paths.

Thanks, all!

 

[Slamfire]

The Lee dipper kit, had the volumetric capacity of each dipper listed, along with a list of powders and the weight each dipper would throw, level full. Black powder was included, I'm assuming FFg, as there was only one weight per dipper. Someday I may run across my kit.

 

[roundball]

The Lee dipper kit, had the volumetric capacity of each dipper listed, along with a list of powders and the weight each dipper would throw, level full. Black powder was included, I'm assuming FFg, as there was only one weight per dipper. Someday I may run across my kit.

Great set of various conversion charts:[url] http://www.curtrich.com/BPConversionSheet.htm[/url]

Lee Dipper Chart[url] http://leeprecision.com/cgi-data/instruct/Dippers.pdf[/url]

 

[Slamfire]

Hey how 'bout that they've upgraded the chart sometime in the last 35 or 40 years. :grin:

 

[CoyoteJoe]

Coyote Joe,

Thanks for the reply, but I think you are missing the point.


[/quote

Well, no, I think you missed my point, which is that it will be a cut-and-try process. When making a horn or antler tip measure I drill short, measure a charge or two and WEIGH them, then deepen the measure a bit and try again. If I knew exactly how many cubic centimeters I needed I would still have to cut-and-try to reach that exact volume. That would just add an additional element with no benefit to the final product. I have a powder scale and adjustable powder measures, I do not have any way to measure cubic centimeters nor cubic inches of volume, much less how deep to run a twist drill to obtain that volume.
If you come up with such a measure it will work only with a liquid. When measuring a granular solid, much depends on the shape of the cavity. A deep cavity of small diameter, such as our common adjustable powder measure, will not give the same weight per cubic centimeter, as a large diameter, short measure, such as a shotgun powder dipper, even though they may hold the same volume of liquid.
As previously mentioned, Lee makes a set of dippers with a chart showing the supposed weight thrown by each dipper but the numbers seem rather suspect. For the[url] 4.0cc[/url] dipper they list as follows; 55.7 gr of fg, 58.8 gr of 2f, 63.7 gr of 3f and 59.6 gr of 4f. Seems rather odd that the 3f weight is so much greater then either 2f or 4f. So even with the dippers and chart you still need a scale if you wish to know exactly what you have. :grin:

 

[In Over My Head]

Coyote Joe:

Okay, in a logical sense you are perfectly correct. :thumbsup:

But in my mind it still seems appropriate to find a dimensional standard to refer to so I have two inputs to verify each other (volume and powder sample).

Different minds work differently. For instance, when I tried to learn to play the guitar I started by making little labels that showed the numeric frequency of every note made be each string at each fret and applied them along each fret. I figured I'd perceive some mathematical relationships to chords and harmonies! :youcrazy:

Okay, that didn't work at all, but it's the way my mind works - I'm VERY left brained!