weighting in on volume

[Zonie]

...On a long rifle, the ball is slowing down before it leaves the barrel. Something about the air pressure ahead of the ball, and the pressure behind the ball starts to equal out....

A number of years ago, Dixie Gunworks did an experiment with a .40 caliber barrel to see what shortening it would do to the muzzle velocity.

They started with a 40 inch long barrel and fired a number of different powder loads using DuPont 3Fg powder under a patched roundball. They recorded the muzzle velocity for each length and load.

With the lightest powder load of 38 grains they got the following:

40" barrel = 1551 fps avg
38" barrel = 1567 fps avg
36" barrel = 1543 fps avg
34" barrel = 1493 fps avg

Note that with the shorter 38 inch barrel the velocity was a bit higher than it was with the 40 inch barrel.
This tends to support that the barrel friction was slowing down the ball during that last 2 inches.

The 36" and all shorter barrels lost velocity when compared with the 38 inch barrel.

Going to the 47 grain and heavier powder charges, this slowing down because the powders gas pressure ran out of energy does not show up.

40" barrel = 1770 fps
38" barrel = 1747 fps
36" barrel = 1735 fps
34" barrel = 1610 fps

 

[hunts4deer]

Amazing! Zonie, Thanks for Posting.

Makes me wonder how much powder is needed to not see any slowdown in a 56 inch 12 gauge barrel (Hudson Valley Fowling Piece)...

 

[csitas]

I can't help my self here. I'm 74, and I guess come from the old school. I was always taught that you measure powder by volume. After you attain your volume , who cares how you duplicate it. It has always been preached, Do everything exactly the same .Soooo, If you must weigh, have at it till your content.Get there a pinch at a time THOUGH.

 

[hanshi]

I'm a volume measurer, too. I might weigh the charge eventually just to see; but I still don't change anything.

 

[sonnyboy]

Do they make an adjustable measure for 3f powder accuracy throwing, or is the world geared up for 2f powder measurement???. My adjustable measure has a smooth side which I can make a corrected (closer throw) measurement. The 50-60-70-80 calibrations are a waste to even try to throw accurate amounts.............sonny

 

[Kansas Jake]

Sonnyboy, muzzleloader shooters almost always measure the black powder or appropriate substitute by volume and not by weight. So, 50 grains of 3f is the same volume as 50 grains of 2f etc. I have sometimes split the 50-60 etc grain calibrations to make 5 grain adjustments. One could also eye ball to smaller differences. For me, most of the time 5 grain intervals works fine in working up a load in larger (50+ caliber) guns. I may make smaller adjustments for small caliber stuff.

 

[Grenadier1758]

Do they make an adjustable measure for 3f powder accuracy throwing, or is the world geared up for 2f powder measurement???. My adjustable measure has a smooth side which I can make a corrected (closer throw) measurement. The 50-60-70-80 calibrations are a waste to even try to throw accurate amounts.............sonny

The tiny difference in volume between 50 grains of 3fg to 2fg isn't going to make any difference in performance. Black powder is not that sensitive to the small variations in weight from one measurement to the next.

You do want to use the same measure for your volume measurements as there can be quite a difference between measures. I have seen up to 5 to 10% difference.

The synthetic black powder substitutes are designed to perform to similar volumes of real black powder.

 

[SDSmlf]

When measuring BP charges consistency will be your friend. Different volumetric powder measures will result in slightly different charges. Find a measure you like and stick with it as you develop your best load. Use it the same way every time - for example, do you tap it to settle the powder?; do you level off the charge by eye or pass a knife edge over it (possibly your measure has a funnel type attachment that levels)?; etc. The actual exact charge weight isn’t as important as it being reasonably consistent from shot to shot. Plus these measures are not calibrated nor held to NIST standards.

 

[Alice1885]

If you want a consistent powder measure, that measures by volume find you an old Belding & Mull powder measure. They are the most consistent out there. Heck the Schutzen guys use them so if they are good enough for them, they are plenty good naf fur us. You won't be disappointed I gurantee it.
Alice 1885

 

[Grenadier1758]

If your most accurate load is 65 grains of 3fg (volume) in your measure, what real difference does it make if that volume of 3fg weighs 63.5 grains or 66 grains on a weight scale? Or that that volume of 2fg will weigh 63 grains? If that volume gives the best performance for target or hunting, use that volume measure always.

Now I can see an instance where you have a super performing load of 65 grains volume that weighs 64.7 grains on your weight scale and you want to pre measure 25 loads for an important match, then use the weight scale to sole out those loads.

A few years ago I ran measurements of 10 volume measures. Most were fairly close to the 2fg weight. 3fg weighed a grain or 2 more at 100 grains setting. The deviation from one measurement to another was about a grain if I was careful and consistent in using the volume measure.

The conclusion I reached was to pick one measure and use that one.

 

[ADK Bigfoot]

I weigh all my charges for match shooting. I use 3F and 2F powder, depending on rifle/fowler being shot. I develop a load based on the most consistent results I get with a specific load. Then I make a powder measure that consistently throws that weight of powder. Deer horn, elk horn, bone, brass, it does not matter. They all throw the same WEIGHT of powder.

If I use a black powder SUBSTITUTE, it throws the same VOLUME of powder as the weighed charge. That is what VOLUME EQUIVALENT means.

At a recent match, I had each of the shooters tell me what load they used. Then I took a sample of each of their thrown charges and weighed them. All shooting 3F black, GOEX, SWISS, or other. Most of their thrown charges, based on the markings on their measures, were WAY OFF. They were amazed at what charges they were actually shooting.

GOEX 3F is not the same as SWISS 3f is not the same as PYRODEX RS is not the same as TRIPPLE 7 (777). You have no idea what you are shooting unless you weigh your charges of Black Powder and then convert to Volume Equivalent of substitutes. And with Triple 7 (777) or SWISS, a reduction in loads may be advised.

Most store-bough measures I have seen/used are not even close to accurate weight-wise, and must be calibrated against an accurate scale. Otherwise, you are just guessing.

ADK BIGFOOT

 

[longcruise]

The belief that the volume markings on measures are meant to match the weight of a particular granulation of powder is completely erroneous. I'm afraid our hobby is plagued with these types of "facts" that are often based on someone's assumptions or speculations.

As ADK points out above, every brand of powder has it's own ratio of actual weight to volume. I have compared multiple brands of powder weights thrown from the same measure and the variations are substantial. And, comparing the velocities of those same powders you migh expect the heavier (by weight) charges would generate higher velocity but once again, it is not borne out.

Next time you shoot targets, try shooting nine shots at a target at 50 yards. On the first three shoot your best accuracy charge and mark them on the target. Then shoot three at 5% less than the accuracy charge and mark those. Next, three at 5% more than the accuracy charge and mark those. Then post a picture of the group along with your thoughts on the results.

That's your mission should you choose to accept it! this post will not self destruct in five seconds cause it just ain't possible.

 

[nkbj]

There's some guns you want to weigh for


(I'm right proud of my box)

and some that don't matter.

 

[longcruise]

That's a nice box. For pistols?

 

[45man]

Well, with around 66 years of BP shooting, there is nothing I have not tested. So I have to say my experience was different and weighed charges always did worse for me. It does not matter how much a measure holds at the mark since the load work is still done with it. Consistency is the key. Even modern BR shooters have found the brass case airspace varies so they load the same 5 cases at the bench without a scale. They tweak a powder measure for conditions.
BP does not explode as the coatings and grain size control burn and it burns progressive the length of the barrel. It just leaves more ash. Too much powder for the barrel can exit the muzzle and we have had plugs of powder exit to burn in the grass. Powder that does not burn adds to ball weight and recoil. That will also reduce velocity so adding more and more powder works in reverse. I don't know about modern subs but Pyrodex works just like BP, too much is no good. Chronograph tests proved it.
I have every BP here, Kick, Elephant, Swiss, Goex, Clear shot, Pyrodex and 777. All in every grain size too and all work different. But every one is a volume equivalent to load and not weighed.

 

[mlshooter]

Here is a web page which gives the densities and packed weight of a number of powders:
http://ctmuzzleloaders.com/ctml_experiments/bp_burning/bp_burning.html

 

[Pete G]

Some members of the Long Range Muzzle Loader discussion list undertook some basic testing in 2001 to assess the Effects of Temperature, Humidity, and Barometric Pressure on Moisture content of Black Powder. You might find them of interest.

His mind is made up, don't confuse it with facts.

 

[mlshooter]

Unfortunately, the link seems to be broken...

 

[DAKurth1]

When measuring BP charges consistency will be your friend. Different volumetric powder measures will result in slightly different charges. Find a measure you like and stick with it as you develop your best load. Use it the same way every time - for example, do you tap it to settle the powder?; do you level off the charge by eye or pass a knife edge over it (possibly your measure has a funnel type attachment that levels)?; etc. The actual exact charge weight isn’t as important as it being reasonably consistent from shot to shot. Plus these measures are not calibrated nor held to NIST standards.

I agree with SDSmlf, consistency in filling your powder measure is imperative.
I’m fairly certain that in every container of 2f, regardless of manufacturer, there exists some amount of 3f and 4f.
Unless you sieve every batch of powder you are going to load with, you have no idea of exactly what burn rate you are going to get out of every thrown charge.
I simply measure by volume for my muzzleloaders and by weight for my BPCR cartridges!

 

[nkbj]

That's a nice box. For pistols?

It's for target rifles. A bottles will hold 150 grains, way more than I ever pour down a barrel.