FFFg Density?

[Steve Swartz]

What is the density of Goex FFFg or where could I look it up?

I need to know how much powder (in grains) is needed to completely fill my "patent chamber" (0.06 in3).

So if I just knew what the grains per cubic inch were of black powder . . .

Steve in North Texas

 

[Joel/Calgary]

The densities that I've seen posted vary by brand, granulation, and lot/batch somewhat, but most modern firearms powders (as opposed to fireworks or blasting powder) were close to the density of water, 1.0g/cc. IIRC, they're more often less (down to maybe 0.96/cc) than over (up to maybe 1.03g/cc). You could look up the conversions for grams to grains and cubic centimeters (or mililiters) to cubic inches, or use the density of water to calculate it. I'd look them up, but it's late and I've gotta get to bed.

Joel

 

[arcticap]

See chart #2:
[url] http://www.curtrich.com/BPConversionSheet.htm[/url]

 

[Grenadier1758]

The conversion that I have come up with is based on an old rule of thumb that you have 10 grains of black powder for every 1/4" of depth of a 29/64" drill bit.

This does hold true for GOEX powders of a couple of years past. Most modern volume based powder measures are consistent with this volume for GOEX black powder.

So to answer your question for GOEX black powder there are 248.05 grains / cubic in.

In most of my measurements of the weights of powders thrown by these measures there is no significant difference in weight of fffg GOEX or ffg GOEX.

Elephant was 10% heavier. I need to make an update to my measurements.

 

[Steve Swartz]

Thanks all.

After much finagling looks like my ~0.06 or so cubic inches is very close to a milliliter (makes sense- pedersoli gun!).

And it looks like a milliliter holds right around 15 gr of FFFg.

I crunched this several different ways with data from different websites and applied my trusty CRC manual . . . and it all came out fairly consistent.

O.K., so given that it takes around 15 gr of powder to fill my chamber . . .

. . . would I need a load of at least 15 gr for optimum consistency?

The mfgr recommends 12 gr load- but this is leaving an airspace over the powder and does not allow the ball to compress the load firmly.

Bad mojo?

Steve in North Texas

 

[arcticap]

The pistol might require 15 grain charges but maybe not because it has anything to do with airspace, but velocity.
There will always be some airspace somewhere under the ball, the powder chamber may have slightly less capacity over time due to fouling, and its size may serve to inhibit powder contamination.
Maybe the size of the Carlton's powder chamber is even designed to eliminate powder compression as a variable.
I recall reading about an accuracy test involving .22LR cartridges and whether it made any accuracy difference where the powder in the case was located, i.e.- under the base of the bullet or more directly in front of the rimfire primer. The experiment involved raising the gun from a lowered position and test firing (to promote powder placement under the bullet), and then lowering the gun from a muzzle up position and test firing (to promote powder placement closer to the primer).
Despite the relatively large ratio of airspace in a .22LR case, there wasn't any noticiable difference in accuracy.
Maybe testing will reveal some accuracy differences between the different powder charges in your pistol, but the reasons would still be open to interpretation, especially without a machine rest, scope etc...
Testing everything is fun... :hatsoff:

 

[paulvallandigham]

It may not make a difference in a .22 LR casing, but it does in a .38 spl. casing. placement of the powder seems to be the one explantion for some of the ruptured casings and cylinder walls on revolvers, that has withstood testing, using verified small amounts of bullseye.Its believed that the high pressures are a result of two pressure waves hitting each other, when the powder is out against the bottom of the bullet, and burns, producing one wave that now heads back toward the base of the casing. At the same time, the primer also prduces a shock wave that is racing toward the base of the bullet. The two meet in the middle, and act as an overload, bursting the casing, and usually the chamber. When the powder and primer are together, they produce one pressure wave that is going towards the base of the bullet, and pushing the bullet down the barrel. This doesn't happen in these casings when you use a bulkier powder that fills the case batter.

In a BP gun, a little air space can go a long waay, depending on caliber, and the powder charge used.

I recommend seating a ball in all flintlocks so that it just touches the powder charge, so that there is loose air in and around the granules of powder behind the ball, and the powder is not compressed.That practice produces the lowest SDV. In Percussion guns, you get the lowest SDV doing the OPPOSITE. Compress the powder in a cap and ball gun. The more consistent the compression, the better the SDV. I also recommend using FFg powder in flintlocks, regardless of caliber, while using FFFg in all percussion guns, regardless of caliber. The larger granule of powder burns quicker over all in flintlocks, because the extra air between the granules helps internal ignition. In Percussion guns, the small sized granules pack together better, and the percussion cap burns a hole right through the entire powder charge, to ignite the whole thing off fast, and consistently. Hence, the smaller SDV.