Author Topic: Confusing. Powder charge. Weight or Volume? (Read 869 times)

Leadlauncher · « **on:** January 01, 2004, 06:00:26 PM »

G,day & Happy New Year from Down Under. I'm confused with some people telling me that there is a difference in dispensing a powder charge in grains of weight & volume, & that volume is the best way to do it. How can this be? I have never seen anywhere a powder charge in volume? I normally use my Pact dispenser / scale combo. Should I now use my new Redding BR50 instead? Your thoughts would be appreciated. Kind regards.

Donna · « **Reply #1 on:** January 01, 2004, 06:58:59 PM »

Hello Leadlauncher,

In short dont worry about it just keep on doing what your doing, going by weight. Technically a powder thrower throws powder by volume not weight and we measure powder by either volume or weight but if we go by volume we measure that volume according to weight. For any given volume of any type of powder has a given weight and the reverse is also true, for a given weight of any type of powder there is a given volume. So it makes no difference if you throw a given volume or dispense a given weight of powder as long as the two are equal, it is the same thing.

Donna :wink:

Arizona Jake · « **Reply #2 on:** January 02, 2004, 02:56:06 AM »

Leadlauncher:

Donna is correct. Most of us use a powder measure which dispenses a volume of powder. However, there is a very small variation in the weight of the charge thrown from load to load, as the powder in the measure becomes more compact as it settles under its own weight. As the powder level drops after a number of loads have been thrown, less powder is forced by gravity into the charge column of the scale, tending to produce lighter loads. hence, we use the measure to dispense a volumetric load that approximates the desired weight and use the scale to verify the correct weight or to make adjustments. Clear as mud? :wink:

JimInNJ · « **Reply #3 on:** January 02, 2004, 07:00:19 AM »

Were the folks who said volume is the best way to do it perhaps black powder shooters?

- Jim

nomad · « **Reply #4 on:** January 02, 2004, 07:41:29 AM »

Many (most?) of the short-range stool shooters I know load by volume rather than weight. (OK!, The shameful secret is out, I used to be one! It's probably where I got my bad habits.)
The long-range types still weigh AFAIK.
As I always understood it, the theory is that volume is less subject to conditional variations that affect accuracy until small velocity excursions become significant.
Most ATC folks with whom I remain in contact weigh their 600 yd loads and I don't know any 1000 yd shooters who load by volume.
Personally, I doubt that, at our distances, it is necessary to weigh charges. The ram line is apparently right on the edge of the point where normal velocity variations are a problem. Testing in my rifle, I've tried it both ways (remember my past history ;-0 ) and I can't see any vertical that carries over...
(IOW, just to amuse myself, I've shot a few groups on the ram line on the same day using identical components loaded with each method and the group size, on average, was not noticeably different. I do use an old Belding & Mull measure and prefer Ramshot ball powder so my thrown charges don't vary by much. YMMV.)

dave imas · « **Reply #5 on:** January 02, 2004, 12:10:02 PM »

you really are a geek aren't you! between you, dan, chris, and luis there are so many propellers whirling about you create your own wind at a match!

nomad · « **Reply #6 on:** January 02, 2004, 01:21:28 PM »

We geeks prefer to be thought of as serious students of the more esoteric aspects of the game...

dave imas · « **Reply #7 on:** January 02, 2004, 03:06:25 PM »

and there you have it. i had to look esoteric up. without you esoterics, the rest of us would be lost with no way out of the desert.

lucho · « **Reply #8 on:** January 04, 2004, 04:49:20 PM »

Nerd Alert!!!!
Nerd Alert!!!

Weight (m) and volume (v) are related by density(d) where

d=m/v

When we measure charges by volume we assume the density is constant and that

m=d*v or m=constant * v

so for a given volume we get a given weight.

However, density is not really constant. If you shake, bump or operate the handle of your powder througher inconsistantly you can shake more or less powder into the dispensing volume of the througher. This will change the weight of the charge.

It is important to have you dispenser mounted firmly to the bench and use a consistent throwing motion to get good consistent weight.

Next time your throwing charges weigh a charge when the handle moves with a good smooth stroke. The weigh one when the handle get hung up for a second when you cut a grain. I fine the second case yields a heavier charge.

Bla Bla Bla Bla.....

Sorry Dave

dave imas · « **Reply #9 on:** January 06, 2004, 05:52:32 AM »

My dear friend... please don't apologize. it is why we love you so much.
dave