Powder Weight Vs Volume Measure Black Powder Vs. Pyrodex

[ghiapilot]

I have been shooting muzzleloader for about a year and have always just used one of the brass adjustable measures to load. Recently I started reloading rifle cartridges using a RCBS balance to measure the powder.
This afternoon curiosity got the best of me and I wanted to see how accurate the brass measures were vs real weight. I set and filled the brass measure to 50 Grs with Graf & Sons FFFG BP, and to my surprise it actually weighed 50.4 Grs.

So next I filled my balance with Pyrodex 'P' without changing the balance, then pored it in the brass measure.... and it filled up to the ~70 Grn. mark. Repeated with Pyrodex 'RS', same results... ~70 grs. Just to verify, did the same test with the BP and right back to 50 grns.

Long story short, should I be loading (from my brass measure) ~70 Grns of Pyrodex to get an equivalent 50 Grn load of Black Powder?

 

[necchi]

No.
If you read the Pyrodex jug it says "Volume equivalent".
Not weight.

That does not mean that you won't need to change the charge when changing from true BP to any one of the faux powders,,
,the same goes for changing between brands of real BP.
It a good idea to separate in your mind the changes between volume and actual weight. You can use either volume,, or actual weight but there is no comparable "standard" within all the different manufactures that can be used that makes them the same.
Many of us here load CF also,, nitro powders and BP are two different creatures.

This stuff Does Not apply to any of my Traditional Black Powder guns;

 

[Zonie]

A given volume of Pyrodex will weigh about 30 percent less than the same volume of real black powder.

The power in that volume of Pyrodex is about the same as the similar volume of real black powder.

That's because Pyrodex and all of the other synthetic black powders on the market are all designed to be weighed by volume.

The result of this is, because it is sold by the pound, a pound of Pyrodex will give the shooter about 30 percent more shots than black powder would give.

Not all of the synthetic powders weigh the same per cubic inch as Pyrodex but I'm pretty sure they all weigh less than real black powder.

That's why it's important to use a volumetric powder measure when measuring out any muzzleloading powder.

 

[robert reed]

http://www.muzzleloadingforum.com/fusionbb/showtopic.php?tid/223072/

Here Is a link to some previous topics on this question.

 

[coloradoclyde]

I have been shooting muzzleloader for about a year and have always just used one of the brass adjustable measures to load. Recently I started reloading rifle cartridges using a RCBS balance to measure the powder.

I also would suggest re-reading your loading manual from cover to cover until you fully comprehend ALL of it's contents.
Lyman and Speer are both good manuals and I would suggest that you buy them both.

Think Safety!...People who blow up their guns do harm to the industry and us all.

 

[Billnpatti]

As Zonie said, the substitute powders will weigh less then black powder for any given volume. That is because the density of the substitutes is less than the density of black powder. Black powder and all of the substitutes are to be measured by VOLUME not actual weight. A given volume of a substitute will perform generally the same as that same volume of black powder. Having said that, I must point out that in reality, an equal volume of some of the substitutes will actually be about 10% hotter than an equal volume of black powder. For that reason, most people will tell you that if you change from black powder to one of the substitutes, to reduce your volume charge by about 10%.

I am sure that you know this but I will repeat it because you can never hear it too many times....Never shoot modern smokeless powder in a muzzleloading gun of any kind.

Because smokeless powders are a progressive burning powder, small changes, as small as a few tenths of a grain, in the weight of a charge will make big differences in the performance. You are doing the right thing by weighing every charge of smokeless powder that you measure out. But, don't bother weighing black powder charges, volumetric measures are fine for them.

 

[cynthialee]

Volume not weight.

This really threw me off when I got the notes from an old timer when I bought his gun. He had his notes in actual weight of powder. Once I figured that out I was able to shoot the gun as well as he claimed it would.

turns out that by weight 72 grains of Pyrodex weighed is about the same as 100 grains of 2F black in a volume measure

I was loading 72 by volume and getting squat. Took awhile to figure it out that his weight measure was actually 100 in a volumetric measure.

Please if you are gonna shoot BP or substitutes and keep notes to pass on, use volumetric measures not weight.

 

[kh0456]

I found this chart is pretty accurate of actual weights of different powders. However I still use a volume powder throw.
http://www.curtrich.com/BPConversionSheet.htm

 

[crockett]

Ghiapilot: always use a volume measure. You can get an upscale volume measure with a cut off top.
Let's talk a little on this subject....
Every batch of substitute powder will be a little different and that includes the same brand. In other words one run of Pyrodex might be a little different than another run of Pyrodex. The manufacturer then adds filler so that every batch is equal by VOLUME. If you measured these different runs by weight the weight measures might furnish different degrees of power and be less accurate. That's why you always use volume. And...Pyrodex always claims you get 30% more shots with their product than real black powder because the weight per volume is less- a pound of pyrodex represents more shots than a pound of real black powder.
Now...I get the sense from your scale that you feel a more accurate method is to precisely measure every load. You are not alone on this. That is a common assumption.
Most of the champion shooters at Friendship pour at the range and use volume measures. They don't accurately weigh every shot and store in speed loaders, etc. before the event. Volume is perfectly fine.
You might be surprised to hear that some modern cartridge benchrest shooters think a volume measure is better than a weight measure. When you reload a modern cartridge you deal with OAL and you set a certain bullet at a certain depth so the space in which the powder occupies is the same from shot to shot. That is a volume issue. The bench rest shooters that measure by volume argue that having equal volumes of a powder are more important than equal weights (This is with modern cartridges). In any event, I point this out to dispel any worries that measuring by volume is less accurate than measuring by a scale/weight.

 

[Okie Hog]

Did some serious experimenting with weighed charges in scoped inline guns as well as conventional guns. In a few cases weighed charges made smaller five shot groups than volume charges. Any difference was very small.

Conclusion:

Weighing charges ain't worth the trouble.

 

[longcruise]

I guess you got the message by now, VOLUME NOT WEIGHT! :haha:

but, I want to point out an error you made when you did the comparison. You did this;

So next I filled my balance with Pyrodex 'P' without changing the balance, then pored it in the brass measure.... and it filled up to the ~70 Grn. mark. Repeated with Pyrodex 'RS', same results... ~70 grs. Just to verify, did the same test with the BP and right back to 50 grns.

This will not work to draw a comparison. To get a true comparison of the weight vs volume, take your powder measure and fill it to the 50 gr mark with pyro and then weigh it. Then fill the same measure setting with the bp and weigh that. Now, you will have the true comparison and you will find that it works out just as Zonie said.

Here is why it does not work. This will involve an addition to the above experiment. Fill your measure with either bp or pyro at a high setting such as 100 grains and then pour it into the scale pan. Weigh it if you like, but it's weight is not pertinent to this experiment. Now pour the powder from the scale pan back into the powder measure. I'm not going to tell you what you will discover. :haha: I'll leave it to you to tell me. :rotf:

While we are on the subject of weight vs volume, here are the results of some comparisons I did between several powders. I set my RCBS powder dispenser at an arbitrary setting and weight the powder charges of the various powders.

BP Weight Comparisons done by measuring charges dropped from an RCBS measure at an arbitrary setting.

Graf 3f
55.9
55.5
55.5
55.3
-------
55.55

Goex 2f
51.1
51.7
51.3
51.4
-------
51.37

Goex 3f
52.2
52.1
52.5
52.2
--------
52.25

Elephant 2f
60.2
60.4
60.4
60.1
---------
60.27

Swiss 1.5f
55.9
56.1
56.4
56.2
------
56.15






Swiss 2f
57.4
57.2
57.2
57.4
-------
57.30

Pyrodex RS
37.0
37.1
37.5
36.8
-------
37.10

Notice that the Pyro results tell you the same thing that Zonie told you.

 

[ghiapilot]

Thanks you for all the great input! I just wanted to make sure I was on the right track before getting to worked up about loads and compensation between BP and synthetics.

Again thanks for your time and knowledge about this topic, it is greatly appreciated.

 

[crockett]

Just remember the volume is always correct. The specific density/weight of Pyrodex may change very slightly from batch to batch so weighed charges may vary in power but the volume from batch to batch will always yield similar results.
I don't know much about drop tubes but if precision is your goal and volume measuring the method, I'm told drop tubes will increase accuracy.

 

[longcruise]

Most muzzle loaders have a built in drop tube of 22 to 48 inches :haha:

 

[nkbj]

Some day when they run me off and there's a bunch of range time I'm gonna use weighed charges.

 

[longcruise]

I have another experiment that may be considered germane to that. Can't post it from my phone so, later.

 

[Zonie]

Most muzzle loaders have a built in drop tube of 22 to 48 inches :haha:

I agree.

For the BPCR shooters, having a drop tube to load those metal do-dads they use is a great benifit.

For us muzzleloaders, we have the drop tube built right into our rifles and shotguns.

Once again, the muzzleloader triumphs over those new fangled things. :rotf:

 

[coloradoclyde]

A drop tube is a loading tool not a measuring device. :grin:

 

[crockett]

Well, I know nothing about drop tubes but here it goes....I thought with a regular measure you might vary how fast or slow you pour in the charge, if you accidentally jiggle the measure the powder could settle down more and allow more powder to fill your measure. To help smooth things out I thought by pouring through a drop tube all the flakes of powder floating down equally, stacked up equally in the measure, and you got more uniform volumes in the measure. I think that's the idea but I'm not sure. I just try to pour the same from shot to shot and I use the cut off top.

 

[longcruise]

I have heard tell of the Long Range ML crowd using a drop tube inside their barrel to drop the powder into the breech area. I think it may be more about keeping powder granules from sticking to the inside of the barrel and failing to drop all the way into the bottom of the barrel.