2f vs 3f volume/weight

[okawbow]

I see posts about people getting the same velocity with lower charges of 3f as compared to 2f.
 
Has anyone done comparisons using weighed charges of 2f and 3f, as opposed to volume measured charges? If so; are the results much different to the volume charges?

It's also been suggested that it's more economical to use 3f as compared to 2f, because one can use smaller charges to get the same velocity. But, is this accurate? After all, a pound of 2f weighs the same as a pound of 3f, but possibly has more volume than the 3f.

What have you found to be the case?

[Frizzen]

I load by actual grain weight so the volume thing doesn't mean anything. You buy powder by weight
not by volume.  Yes about 10% less 3F will give about same velocity as 2F. Accuracy will be what the
gun prefers.

[hanshi]

I try and make my measures to hold a particular weight of powder and then use that measure per volume.  This works out okay but there are weight differences not only between brands of powder but between granulations.  I don't worry about it and just volume measure whatever powder I'm burning and can't tell any difference.  So I guess you can say I measure by weight but it's kind of in the abstract.

[Frizzen]

Actually we all measure by weight.  If you put the volume you  measure out on a scale it would show
you just how much weight in grains you are using. That would be the amount in grain weight your charger
is measuring.

[J Henry]

  I measure by Volume,,,  try this take a table spoon measure of lead shot,,weigh it,,,now take a table spoon of baking powder,weigh it,,,same volume but just a slight difference in weigh....
 The paper that use to come with Pyrodex stated to load FFF 10% less that when you load FF by Volume,,yea yea,  I know pyrodex,,yes, easy to find and it works or has for,,44 years from Florida to Maine.
 Volume is always the same,,weight changes,,,
 Cubic foot of water 62.4 lbs,,,1728 ci,, cubic foot of lead,,, 687 lbs per cubic foot,, same volume.
  The information given here is to explain/show the difference between Volume and Weight,,there is a difference!!!!

[Herb]

I made measures from brass cartridge cases to hold exact weights of several powders.  A measure that holds 100 grains of Goex 2F held 104 grains of Goex 3F (10 of each).   The velocities averaged 1608 and 1652.  Velocities of 100 grains weight of each were 1609 fps and 1663 fps.  I know that doesn't look right, but it is what I got.

[okawbow]

So, it seems that when one uses the same measure of 3f and 2f; he will get more grain weight of 3f and a higher velocity. Obviously some of that higher velocity is because of the higher grain weight, but the same grain weights also produce more velocity for 3f.

I don't weigh my charges, I use an adjustable measure. When set at 90 grains; I notice my .54 with a 48" barrel, kicks harder and cracks louder than the same measure of 2f. The 2f, however, is more accurate, and has less fouling. The difference in impact height is very little at 100 yards.

[Don Steele]

It is absolutely correct that a given volumetric measure will hold more WEIGHT of 3f than of 2f.
It's a small difference, but for those like myself who fixate on small differences...it matters. 

[J Henry]

 SMALL things do matter,, when you load  boost the CUP's
 and LUP's by alot. If small differences made little or no difference,why put all the time into developing a load that works in your rifle?? FFF is more powerful ..less air space,,  like rocks compaired to sand!!!!

[Daryl]

SMALL things do matter,, when you load  boost the CUP's
 and LUP's by alot. If small differences made little or no difference,why put all the time into developing a load that works in your rifle?? FFF is more powerful ..less air space,,  like rocks compaired to sand!!!!

Small differences can make a big difference in accuracy with tight load combinations.  3F, due to it's higher pressures can and will burn patches that 2F doesn't - in some loads and at some speeds.  I'm not sure I get your drift entirely, but many of us try to find the best load for our rifles out of a desire to make them shoot as well as they possibly can, with us at the helm of course.  The more accurate the load, the smaller the size of group you can shoot, no matter your position in shooting it.

[Mad Monk]

When it comes to the weight to volume relationship in black powder life is not all that easy.  Different manufacturers work to different specific standards.

When we discuss the weight of a certain volume of powder the industry refers to this as loading density.  Expressed as grams per cubic centimeter.  Some powder makers work to a tight specification in this while others do not hold the specs that tight.

From work done about 15 years ago.

Goex, at the old Moosic plant, produced our rifle type powder at a loading density range of 0.99 to 1.02 g/cc.  But there were odd lots out of that range.  In thgat range a volume measure set at 100 grains would yield close to 100 grains weight of powder.

The Swiss worked to a different standard.  With their powders one would see a range of 1.06 g/cc to 1.08 g/cc.

Depending on the manufacturer and the powder lots being used you might see lot to lot differences that cancel out the idea that you get more weight of powder in a charger with 3f versus 2f.

This loading density thing is determined mainly during the polishing step in the powder manufacturing process.  As they tumble and "polish" the powder the surfaces of the powder grains are compacted.  Making the grain surfaces dense.  You also wear off sharp corners on the grains and make the grains' surfaces smoother that gives better and tighter grain "nesting" in the measure.  And the longer you tumble it in the polishing barrel the higher the loading density of the finished powder.

The thing about lot to lot variations in loading density was one of the reasons the bp industry spent a lot of time and money in the late 1800's trying to produce powders with perfectly spherical grains of a uniform size.  That would make lot to lot variation very minor.  It also helps to give a more uniform ignition through the charge when the gun is fired.  Uniform ignition and combustion of the charge promotes maximum accuracy by reducing shot to shot variation in muzzle velocities.  Ely once advertised that with their powders they could produce a box of black powder cartridges where the shot to shot variation in the box does not exceed 20 fps.

Mad Monk

[Daryl]

I usually use an adjustable measure for working up accuracy loads for a rifle. When I find "THE" load, I weight that charge that the adjustable measure throws at that setting and make a fixed measure our of brass tubing or ctg. brass to throw that amount - done deal. That measure is attached to that rifle's powder horn.