View Full Version : By Volume vs By Weight
March 17, 2012, 10:49 PM
Ok, I'm sorry if this has been beaten to death but I'm curious. I was playing in the reloading room today. I got out my flask w/30gr spout and measure set at 30 grs. Now when I dump powder from the 30gr spout and from the measure on the scale I get 20.3grs +- with FFg and 21grs +- with FFFg. Does this sound right. The reason I'm asking is I am playing around with some deer antler That I have and I'm trying to make a 90grs by volume measure with it. So do I convert the by volume to by weight and ream out the antler accordingly or just go with the by volume brass measure an get the 90grs in the antler that way. I want the antler to be as accurate as possible. Or am I thinking WAY to deep on this one??
March 17, 2012, 10:54 PM
30 grains of real black ought to be the same weighed or measured. None of the subs will.
March 17, 2012, 11:44 PM
The OP doesn’t make sense apart from the fact that from a horn/spout the variations experienced are expected. I could understand the question if there was a bigger difference, which there would be say, between 2F and 3f.
Several things need to be considered.
BP us USUALLY measured by volume. It stands to reason that you can get more 3f powder into a given volume than 2f when both are measured by volume. But the 3f weight will be greater.
While the above is in theory, but also in reality, is true, one ultimately comes upon the paradox of ‘diminishing returns’.
The bottom line is that one achieves the performance desired for the granulation size of the powder. A change in the ‘f’ number will effect performance. An increase of compression, whether more or less, will effect performance.
I can certainly understand how one can ASSUME that BP whether measured by weight or volume would be the same, but that is not the case.
March 17, 2012, 11:52 PM
Sorry I made a mistake in the post. The first one I measured was pyrodex FFg and then Pyrodex FFFg. This antler will be a 90gr rifle measure, So I need to not even worry about the FFFg. I was just curious about the weight. But I'm going to keep hollowing this antler out till I can get the 90grs from the brass measure in there.
March 18, 2012, 01:18 AM
Not to worry about the OP. Totally understandable.
Depending on your own personal requirements just consider the following. Then go for it.
The ‘F’ rating is only an indication of the size of the granule. This in itself if a rather large variable. So an ‘F’ rating between one manufacturer and another may well be different. The amount of compression exerted upon a specific ‘F’ rating from the same manufacturer will also effect performance.
Since we are in the BP arena instead of the smokeless, a whole set of variables need to be considered if one wants the ultimate in performance.
I could go on for pages and pages, but hopefully you get the idea.
March 18, 2012, 01:44 AM
Seems like you are muzzleloading.In Black Powder Cartridge (or anytime using Black) it is critical that there is no air space in the load.Regardless of weight,we want to fill the volume.
Muzzle loader,you just seat the ball on top of the powder.
Where I found my optimum max load was by paying attention to how many shot I could fire without having to swab my bore..just using a lubed patch.
Its like finding rich vs lean in a gas engine.
Too much powder,and after 3 or 4 shots you really have a hard time with the last 6 in of ramming.
Back off a little,and you will be able to shoot 10 or so without swabbing.
That is with Black.I never tried the substitutes
March 18, 2012, 02:28 AM
I got out my flask w/30gr spout and measure set at 30 grs. Now when I dump powder from the 30gr spout and from the measure on the scale I get 20.3grs +- with FFg and 21grs +- with FFFg. Does this sound right.
I initially thought that you were using Pyrodex and that's exactly the right weight for that volume according to conversion chart #1 linked below. It shows that 30 grains of Goex ffg equals 20.5 grains of Pyrodex RS by weight.
March 18, 2012, 02:28 AM
You are right. Airspace is what the issue is here.
But we are not talking about air space between the powder and the bullet. We are talking about the airspace between the individual granules of the powder themselves and effects compression of a particular granular size has on the desired effect.
March 18, 2012, 03:25 AM
Thank you Articap for posting the link to that chart, its saved in my favorites and printed out. Good stuff
March 18, 2012, 05:40 AM
Another factor to be considered (or not) is that the volume/weight relationship - even in powders of the same granulation - may well change with manufacturer. A given volume of Swiss FFg will often weigh more than the same volume of Goex FFg, as much as 10% more.
Y'know....we read so often about "you don't measure BP charges by weight; you measure by volume." or some such that one easily gets the impression that something bad will happen if you weigh charges. Of course, nothing bad will happen, though it is difficult to do in the field with a muzzleloader (unless one brings prepared loads). When I am shooting my BP target pistol, I am using weighed charges every time. When I drop powder into 45-70 cases, the measure has been calibrated with a scale.
Another idea that may well be a myth is the "no airspace allowed". Makes sense in muzzleloaders.....but in cartridges? Aside from a negative effect on consistent velocity, why should airspace be any more of an issue with BP than with smokeless?
Just askin', not arguin'.
March 18, 2012, 06:45 AM
The chart provided by arcticap is handy and shows that the fake powders are less dense than real black. A given load of black is to be substituted with the same volume of Pyrodex, etc., not the same weight.
The concern with airspace over a black powder load is the risk that the burning powder mass will hit the base of the bullet like an obstruction and ring-bulge the barrel.
I have always wondered why the Scheutzen shooters don't ring barrels with their breech seated bullets and wadded powder only cartridges behind them. The answer seems to be that they do, just that the ring is where it does not affect accuracy of the breech seated bullet or extraction of the brass. Not every time, but in some cases.
I also wonder about the Swiss Federal .41 and its Wild System ramrod with shoulder to stop the bullet about .10" over the standard powder charge. I don't guess a ring would be noticed there, either.
March 18, 2012, 10:28 AM
I am playing around with some deer antler
I see you are really getting into this Buckskinner stuff and that's great. I have made mine out of antler as well but lately I make them out of horn as they are easier to work with. I go by volume with the use of a calibrated powder measure that has a cut-off spout on top. I've see some M/L guys tap their measures down and top off, before pouring and not sure what this does, especially when they would pour into another measure. .... ;)
Might make a minor suggestion; If you like that 90grns. as your max, thats fine and I put a brass cross pin at a 70grns lower level. I then scribe my lower level on the outside of the horn tip. .... :)
Keep in mind that a RPB is very forgiving and a few grains off, either way, makes little difference. ... :cool:
Be Safe !!!
March 27, 2012, 09:19 AM
I have posted at least 50 times about this subject so here goes another one. Black powder was always weighed in the early days of cartridge shooting. Don't believe that, then find the old boxes and see what they say. They will have something like these cartridges were loaded with 28 grains of powder.
It does not say black because it was just called gun powder.
The 44-40, 38-40, 45-70, 45-90, 45-110 and many others are telling you how much powder they contain by "WEIGHT" not volume. For those who don't know, the back number refers to the amount of powder in that ammo. fThe original 45 Colt round was known to be loaded with 40 grains of powder.
The Buffalo hunters would make them a powder flask or dipper by weighing the charge and finding the correct size spout or cup that held that amount.
Black powder for the most part will show a difference in loads once you have used an amount that is either -+ 5 grains.
People all the time like to compare Swiss against our Goex and say it's a better powder because it's faster for one thing. This is true but for a reason.
Compare the two under a microscope and you will find that the Swiss and all other foreign made powders are much smaller in grain size which burns faster. The Swiss 2F is about the same as Goex 3F and so on down the line.
The advent of the term, "LOAD BY VOLUME" did not come about until the first production of Pyrodex came available for sale. The reason is that Pyrodex and all other subs are much hotter than the real BP and therefore the same or equal in volume will give you the same results.
Some people today say that they are BP shooters when they are shooting the subs and this is not true.
The subs don't produce the fire, flames, sparks and loud "BOOM" given off by the real Black Powder.
If you read the older BP books and manuals you will find the loads are given in grains and not volume. Read the T/C loading manuals from the 70's and see what they say.
Somehow someone during the time of Pyrodex said you load by volume and another person picked it up and printed that BP guns are loaded by volume.
I'm like Elmer Keith on this one as "I WAS THERE" working in a gun store and remember when the salesman came in with this new powder that was going to change the BP shooting world.
What it did was to blow up and kill the inventor.
Before you post a you don't know of what you speak, do some good research.
I even have my original T/C manual that list all loads with weighed charges.
One quick note that every BP shooter and as far as that goes all reloaders should know is that different lots of the same powder may give different charges. Measure and keep lot numbers together. Enjoy your shooting David
March 27, 2012, 10:47 AM
May have been answered, I didn't read all the posts.
The volume measure for Pyrodex is an equvilant for black powder by weight. While measures do vary they are close. Don't mess with actual weight as you could overload. Stick with the measure. I make a lot of measures from antler, wood, etc. Try to use a drill bit about the same diameter as on your brass measure and drill to same depth. If you get more than you want, a little wax dribbled into the bottom will reduce the volume to where you want it.
March 28, 2012, 06:30 AM
If you use Pyrodex or anything other than black powder and you are drilling out a deer antler for a powder measure, just remember that you will have to calibrate that powder measure by weighing the charges of black powder that that measure throws, not Pyrodex.
You can also weigh the amount of water that the measure holds, water's density is very close to the density of black powder.
If you want 30 grains, you can also pick up an empty .223 case and use it as a powder measure.
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