Powder measure kit scoops inconsistent with the included chart?


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upjeeper
May 4, 2009, 01:37 PM
I've got a set of powder measuring scoops (Lee I think).

The problem is the chart says an "039 scoop" should be 4.8 grains of 700x, but that scoop weighs out to something like 8-9 grains where an "020 scoop" weighs out to close to 4.8 grains.

Any idea what the discrepency is? I assume when I load I should go by weight of the powder. (it's new powder BTW)

Thanks much!

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CTSigLover
May 4, 2009, 02:09 PM
Powder is always referenced by weight, not volume, a grain is a unit of weight... but powder is often dispensed by volume... there in lies the rub!

Where things get tricky is that most powder measures (not scales) measure by volume in cc's. To convert between weight (grains) and volume (cc) you need to cast your mind back to high school chemistry where they taught you that density equals mass (we will use mass and weight interchangeably... I know they are not the same... but they are close enough for our purposes) divided by volume.

Once you know the density of a powder, you can easily convert back and forth between weight and volume.

Where do you find the density of powders you ask? You look at the file which I have attached wherein you will find density, and its inverse "bulk" for most major powders.

While volume and weight are proportionally related through density, WEIGHT ALWAYS TRUMPS VOLUME WHEN DETERMINING CHARGE. That is why you check every few powder drops on your scale to ensure that the volumetric measure is throwing the proper WEIGHT.

Now, on to your question... I have used the Lee dippers in the past, and they are marked with their volumetric measurement in cc's. The dipper marked 0.7 holds 0.7 cc's of powder, which should have a specific weight given that powder's density. If you are getting large discrepancies, between what a given volume of powder should weigh, and what it does weight, you have to isolate and examine each variable. Is the volume actually what you think it is? Is the powder density correct? Is your scale working properly.

Let's look at an example using Alliant's Unique...

The powder density chart shows that Unique's density is 9.158 grains/cc, so if you use a Lee Dipper that holds 0.7 cc's, you weight should be 9.158*0.7 = 6.41. If we look at the Lee Dipper chart, we see that indeed a 0.7cc scoop of Unique should weight 6.4 grains. It works in reverse too... imagine you were using a volumetric measure, and you wanted to use 3.5 grains of Unique in some loading, where should you set your volumetric measure? Simply divide 3.5 grains by 9.158 grains/cc. Units of grains cancel each other, and you are left with 0.38218 cc's. Check your work, whats 0.38218 multiplied by 9.158 grains /cc? Yep, 3.5 grains. Keep the dimensional analysis straight, and you can't go too far wrong... but ALWAYS CONFIRM VOLUMETRIC MEASUREMENTS WITH A GOOD SCALE!

Hope this helps... remember volume may be easier when loading ammo in bulk, but charge weight is the gospel.

Good Luck

loadedround
May 4, 2009, 02:25 PM
In using the Lee scoops, I would imagine that developing the same technique on each scoop would be essential to getting actual weights. I now that using bushings in shootshell loading requires the same motion repeatedly to get the same powder drop. Another poster mentioned powder density, it is also possible that if you are using an older powder and it had absorbed moisture and therefore changed it's density(read weight). Just my thoughts. :)

rcmodel
May 4, 2009, 02:40 PM
Sounds to me like you have a set of the old Lee companies powder dippers.

They don't play well with the new Lee companies powder dipper charts.

The old companies dippers had meaningless numbers.
The new current Lee companies dippers are marked in CC's capacity.

rc

Mal H
May 4, 2009, 02:51 PM
Powder measure kit scoops inconsistent with the included chart?Frankly, I would have been more surprised if the scoops were consistent with the chart!

I have a set of the Lee dippers and use them all the time, except for measuring out powder loads according to their charts. If you can get very consistent with the method of filling the dippers, they aren't bad, but they won't give you the weight of powder that Lee says they should - I'll pretty much guarantee that. So you get a good scooping routine, measure several scoops for the actual weight using a scale, then you're good to go for some relatively fast reloading for plinking or casual target work.

rcmodel
May 4, 2009, 02:56 PM
"039 scoop" should be 4.8 grains of 700x, but that scoop weighs out to something like 8-9 grainsThing that concerns me is, he getting a double charge of 700X!!!!

Yikes!!! :what:

I'd be tossing the dippers & the chart in the nearest trash can!

rc

Walkalong
May 4, 2009, 02:58 PM
At least he weighed it, and did not blindly trust the chart. Smart fellow. A double charge of 700X would ruin your day.

rcmodel
May 4, 2009, 02:59 PM
+1

Very Smart!

rc

Otto
May 4, 2009, 03:23 PM
I've got a set of powder measuring scoops (Lee I think).

Good, now throw them in the dumpster....

upjeeper
May 4, 2009, 05:14 PM
man, some good info here!! thanks guys

rcmodel - you're exactly correct. They do appeared to be an older set. What I get for buying off ebay without pictures...

anyway, i guess theses dippers should be ok as long as I measure the weights out and know how much powder i'm dealing with each time. I'm actually a mechanical engineer so i'm pretty familiar with volumes, masses, pressures, etc - and really do not want to cause damage to my tricked out XD.

thanks for the lesson folks, MUCH appreciated! i'll make sure to pull the rounds that have a double charge.
bad mojo...

MMCSRET
May 4, 2009, 06:29 PM
As I once heard: Mechanical engineers build weapons------Civil engineers build targets!!!!!!!

Roccobro
May 4, 2009, 07:19 PM
CTSigLover- Your post screams *STICKY!!*

Good job!!!

Justin

Randy1911
May 4, 2009, 08:52 PM
Just remember, all powder measures measure by volume. The difference is that you adjust the volume of the powder measure to get the weight of the powder charge you want. With the dippers, you get a set volume and the weight you get is according to the preset volume. The chart is approximate weight.

lgbloader
May 5, 2009, 12:51 AM
I really like Lee dippers. I used to use them all the time with my 1010 scale for rifle until I got my Chargemaster combo. with practice, it goes quickly. when I charge the hulls for my slugs, I still drop and trickle charge with the dipper. I would not get rid of them for nothing.

LGB

bullseye308
May 5, 2009, 09:44 AM
Weren't the Lee dippers based off of Bullseye powder? If so, any other powder that didn't have the same density would not be accurate. That is why you use a scale to verify everything.

rdhood
May 5, 2009, 09:55 AM
Actually, Lee has a dipper powder chart for volume to grain for most common powders:

http://www.leeprecision.com/cgi-data/instruct/Dippers.pdf

Even with the chart, you should weigh a few dippers of your particular powder on a scale and make sure that 1) it is dipping out the anticipated amount of powder and 2) you can do it repeatedly and accurately.

Mal H
May 5, 2009, 12:29 PM
Weren't the Lee dippers based off of Bullseye powder?No, the chart gave weights of a large number of powders when measured out with the dippers. For example, the 039 dipper like the OP used can measure from 4 grains up to almost 10 grains depending on the powder type being measured (showing the wide range of powder densities).

SASS#23149
May 5, 2009, 12:53 PM
are you dipping a full scoop and then leveling off the charge with a credit card or the like? As I recall that is how we did it years ago,and it worked great.

David Wile
May 6, 2009, 12:41 AM
Hey folks,

Old Lee dippers or new Lee dippers - they are all useful if you throw out the charts and use a scale to find what weight the dippers are measuring. I have a number of dippers I made from old shells with a wire handle soldered to the case. Any dipper can be useful if it is used with good common sense. I would also strongly recommend that no hot loads should be made with any dippers. Dippers simply are not accurate enough to make load at the upper end of the pressure levels. When making medium loads, however, dippers can function quite well. Forget the charts and trust your scale when calibrating what the dipper is throwing.

Best wishes,
Dave Wile

sonick808
March 7, 2010, 11:57 PM
don't throw the dippers in the trash! the chart is the offendor, not the dippers

save the dippers!

EDIT: ack, found this thread via google, didn't check the date. sorry!

bds
March 8, 2010, 12:21 AM
EDIT: ack, found this thread via google, didn't check the date. sorry!

:)

Old Lee dippers or new Lee dippers - they are all useful if you throw out the charts and use a scale to find what weight the dippers are measuring.
I guess you can always measure your powder charges and make your own short chart. Some suggested putting crumpled aluminum foil at the bottom to custom tailor your charge too.

Whatever works as long as your charges are consistent.

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