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View Full Version : Is it wrong to first measure BP then weigh from there


6666
June 12, 2010, 10:40 PM
Given that Black Powder should be measured not weighed when loading.

would it be wrong to do this procedure?

If you took a can of BP, given that hopefully all the powder in that one can was manufactured the same, and you first MEASURED about 5-6 charges
and weighed each one, to get an average.

Would it be wrong to then just weigh the same charge for the rest of the tin, maybe doing a test measure and weigh every now and then ??

or should you just keep using the measure ?

the rifleer
June 13, 2010, 12:07 AM
Well i dont know why that would hurt, but that seems awfully time consuming. I dont think that you could have enough of a variance to hurt anything as long as you measured correctly and weighed it exactly the same every single time.

arcticap
June 13, 2010, 02:35 AM
The measurement of volumetric grains of ffg black powder is supposed to be equal to the weight grain measurement of ffg black powder.
So it's never really wrong to weigh black powder charges if someone wanted to be that exact.
However there are different types of black powder that have a big difference in volume and potency. For instance, homemade black powder usually isn't compressed anywhere near as much as commercial black powder is [if at all] and therefore equal weights of it wouldn't even fit into the same cartridge case or revolver chamber.
And also all of the substitute powders are manufactured to have relatively equal potency to black powder by volume and not by weight.
The exception is 777 which needs to be reduced by 15% volume.
So then volumetric grains of any powder is easier to measure out in the field and at the range in the traditional way by using a powder flask, with a calibrated or metering spout, a powder measure, a powder scoop or such.
Lead shot is also usually measured in the field by volume the same way by using the same powder measure and not by using a scale. The traditional rule of thumb has always been to use equal [volume] amounts of shot and powder. And in actual practice using that method works really well.
Here's a conversion sheet that shows conversion weights for the various substitute powders:

http://www.curtrich.com/BPConversionSheet.htm

Smokin_Gun
June 13, 2010, 03:08 AM
Down range it wouldn't really matter a bit...weighing will jus' take time away from trigger squeezin'...iifin ya fallow me.

Ya don't need to...but try it once so it won't be buggin' ya. Volumetric mesasurements no matter what you use... a dipper in CCs, an incremented measurer, a shell case, antler or steer horn tips...the repeatability makes the shot groups tight and accurate...even though a grain by volume weighs 1 grain on a scale...weight doesn't remain equal to volume when using BP Substitutes.
;)

Pahoo
June 13, 2010, 09:41 AM
6666
Well covered and even though it is not wrong, there would be no real gain. Your call. :)


Be safe !!!

Doc Hoy
June 13, 2010, 09:58 AM
The various flask spouts and measures are supposed to be accurate from a weight standpoint. By that, I mean that a thirty grain CVA spout should give you a volume of BP that weighs 30 grains notwithstanding the weight/energy ratio of the various different powders.

It might be interesting to measure out the volume of powder from the device that you personally use, then weigh it to see how close it is. I have read on this forum that these spouts are not terrible accurate.

I have personally never tried this. I use the same spout for the volume(weight) I want and get consistent loads. I just assume that the weight is accurate and that may not be a good idea.

Once you find a volume that gives the performance you like from a speed and accuracy standpoint, the weight is not really important.

jhenry
June 13, 2010, 10:23 AM
For any normal shooting, and in fact for your more standard competitions, volumetric measure is just fine. You should however, tap the side of the measure a set number of times to settle it uniformly, then card the top (when competing). It does make a difference in uniformity which you can check yourself using a scale.

That being said, there are just loads of blackpowder bench shooters, and chunk gun shooters, who pre-weigh their charges and keep them in containers at the match. When you start getting to that level it may be of some benefit, but I would wager even then, a properly thrown charge would not be distinguishable from a weighed one, all other things being equal.

kwhi43@kc.rr.com
June 13, 2010, 11:36 AM
I use a "Lee" powder measure and it throws right to the 1/10 of a grain. I
weighted 10 charges on my scale and they were all the same. When I change
lots of powder I always go back and re-weigh and make adjustments because
a different lot of powder will weigh a little less or more. I always want to use
the excact amount of 17.5 grs. for the same veolicty of 1200 fps. Some guys
I shoot with bring their powder with them in pre-weight little bottles. Most of
the slug gun shooters I see, weigh their charges on a scale as they load their
rifles. Here is my set-up

http://i119.photobucket.com/albums/o127/prizzel/0005_filtered.jpg

B.L.E.
June 13, 2010, 10:46 PM
There is nothing wrong with measuring black powder by weight using a scale as long as you use real black powder.

The reason you see the warnings about measuring by volume and not weight is that most black powder substitutes are quite a bit less dense than real black powder and the listed loads are understood to be by volume, not by weight. If you weigh Pyrodex instead of measuring it by volume, you will get a serious overload.

Rifleman1776
June 14, 2010, 07:12 AM
The weight will vary with make of powder and granulation.
You are gaining nothing by weighing. Real bp is not consistent enough to guarantee the same results shot to shot even if you weigh to a 1/10 of a grain.
Measuring is fast and safe. You will gain nothing by screwing around with a centuries old system.