By weight or by volume?

[poinlaw]

New guy question. I have worked up a good load using a sliding powder measure that shows 100 gr. on the sliding scale at my selected charge. I weighed the charge on my 5-0-5 powder scale and it weighs 70 gr +-. This is Pyrodex RS, which they say is equivalent to FFg. Having measured smokeless powder charges in centerfire cartridges for decades by weight, I am unused to measuring by volume. I dont even know what a "grain" by volume is. It doesnt matter too much, because I will measure my load by volume and not weigh it. Just wondering what the smokepole protocol is. Thanks.

 

[poinlaw]

Never mind. I just saw my question answered in spades on a similar thread. I've got to learn how to do a thread search. Thanks anyway.

 

[Nobody85]

Yes sir. Always measure black powder by volume. Now some of the nice powders like Swiss are denser, and you can feel the difference in recoil given the same volume charge as other makers. Black powder is much more forgiving than other propellants though, so as long as you play with your load by volume you should be fine.

 

[maillemaker]

Grains is a measure of weight. There are 7000 grains in a pound, thus one grain is 1/7000th of a pound.

If you want consistent and accurate charges of black powder, a precision scale is the way to achieve that. This is not to say that you cannot dispense powder by volume and get very consistent and accurate charges that way also. But volumetric dispensing is prone to changes due to process. The scale is the same every time. If you want to dispense 80 grains of black powder, the only way to be certain you are getting 80 grains is to use a precision scale.

Pyrodex is different. It is designed to be dispensed by equivalent volume of X grains of black powder. So if 80 grains of real black powder fits in a container, then you would use the same container to get an equivalent charge of Pyrodex. But it would not weigh 80 grains, since Pyrodex has a different density than black powder.

 

[hanshi]

A possibly easier way to go about it is to find your load by using a volumetric measure. Once you have the accuracy you want weigh a few of the charges and average them out.

 

[Grenadier1758]

Most of the volumetric measures are quite close in measuring the weight of 2fg black powder. Most volumetric measures of 100 grains of black powder will weigh 100 grains on a weight scale. Usually, the difference is less than 3% and the weight of subsequent measured loads will be consistent.

Pyrodex is about 70% the weight of black powder. I did not do the measurement test with Pyrodex.

My test is getting dated now as I did the measurements on July 20, 2001. My most consistent measure was one from the Hawken Shop and the data follows,

Hawken Shop
Grains	Diameter
100​	0.412​
Measured Depth	Calculated Grains - Vol
1.128​	99.37​
1​	99.5​
2​	100.0​
3​	100.4​
4​	99.0​
5​	100.2​
6​	100.0​
7​	101.1​
8​	100.3​
9​	100.4​
10​	100.6​
Average	100.15​
Std. Dev.	0.58​
Maximum	101.10​
Minimum	99.00​

The measure with the worst performance was one I bought that was also the smallest in diameter of my adjustable measures. I think that had a factor. Even then the difference from maximum to minimum was slightly less than 3 grains. Useful enough for using real black powder.

Gostomsky
Grains	Diameter
100​	0.430​
Measured Depth	Calculated Grains - Vol
2.907​	104.71​
1​	107.6​
2​	107.8​
3​	106.0​
4​	106.0​
5​	106.2​
6​	105.8​
7​	106.8​
8​	106.1​
9​	108.9​
10​	109.0​
Average	107.02​
Std. Dev.	1.23​
Maximum	109.00​
Minimum	105.80​

Could be just a bad look at the markings that I was off by 7 grains.

When developing loads, be sure to use the same measure for all shooting.

 

[new2bp]

Coincidentally, BP is just slightly less dense than water. A 30 carbine case holds 21gr h2o and 20gr BP. Saw a chart (I think somewhere on this site) from an old article/book that showed goex 3Fg "real weight" was within a percent or two of "grains equivalent volume" (ie, "100gr" of goex really did weigh right near 100gr). Chart showed multiple powders, and some were over some were under and some where just the same.

With real BP I'd be confident enough with going with measured-by-weight loads. As you can see with the replacements (Pyrodex, 777 et al) the volume/weight ratio is nowhere near to close and assuming it is could very quickly get you into dangerous territory (with a fixed-barrel gun. a C&B revolver would self-limit to a safe level of Pyrodex simply because the cylinder is only so long and too much powder will make the bullet stick out enough to keep the cylinder from rotating)

 

[DixieTexian]

You can load substitutes by weight as long as you build up a load using volumetric measurements first. After you find a load it likes, fill up your measure and weigh it. You probably need to do that at least ten times. If the weight is consistent, go from there if not, do it some more to average out the variation. From there, you can make up several premeasured loads of slightly varying weights and further fine tune your load for optimal accuracy. The other big catch is that you have to try and be as consistent as possible with the amount of pressure you put on it while seating the ball or bullet. Some powders, like triple seven, have a reputation for being more sensitive to the amount of compression applied. That said, make sure you build up your initial load using a volumetric BP measure. I know it's been mentioned before, but if you use the equivalent weight of a substitute that you use with BP you might be in for a bad time.

 

[dave951]

Guys- here's the truth about volume v weight.

You can use your scale to set your powder measure. That's going by weight. BUT once set, your powder measure uses the VOLUME you set it to. This is for EACH and EVERY powder measure out there besides the self dispensing auto scale types.

IF you're going to use a sub, set your volumetric measure first with real black, then use the sub. The mass of the subs varies considerably relative to the volume when switching to subs v the holy black.

 

[Johnny Tremain]

they say is equivalent to FFg

They Lie

Always by volume