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Old May 28, 2013, 07:32 PM   #51
spacecoast
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Quote:
It is correct that tapping the dipper handle compacts the powder and can lead to an "over-charge" if the loader is relying on the Lee chart.
Tapping the handle can do nothing but remove powder unless you are putting the dipper back in the powder afterward, so I cannot understand this statement. After "dipping" (actually immersing the dipper the way Lee intended) I usually give it a light tap to level off the powder. In this way I believe I throw very consistent charges.

It's true that the chart is not accurate for some powders, hence the need to calibrate each dipper for each powder using a scale.
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Old May 28, 2013, 10:21 PM   #52
Lost Sheep
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Quote:
Originally Posted by spacecoast
Quote:
It is correct that tapping the dipper handle compacts the powder and can lead to an "over-charge" if the loader is relying on the Lee chart.
Tapping the handle can do nothing but remove powder unless you are putting the dipper back in the powder afterward, so I cannot understand this statement. After "dipping" (actually immersing the dipper the way Lee intended) I usually give it a light tap to level off the powder. In this way I believe I throw very consistent charges.

It's true that the chart is not accurate for some powders, hence the need to calibrate each dipper for each powder using a scale.
Picture it this way:

Fill the dipper to the point where powder is mounded up above the rim of the dipper. Tapping the dipper will knock some of the mounded powder granules off. Tapping will also "settle" or "compact" some of the granules inside the dipper. As the dipper contents compact, some of the mounded "extra" granules will now be below the rim and will wind up staying in the dipper.

I don't think there will be a LOT extra (enough to qualify as a dangerous overcharge if you are not already at the limit), but how much compaction is achieved before the mound either falls over the rim or settles into the bowl could cause charge weight variation of a degree unsettling to many of us.

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Last edited by Lost Sheep; May 29, 2013 at 12:21 AM.
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Old May 29, 2013, 07:09 PM   #53
SL1
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I think you guys are misremembering the part where I pass the previously-tapped dipper under a straightedge to level the surface. Prior to that step, the dipper is heaped with powder above its lip. Tapping it has simply caused some of the powder to sink below the level of the dipper's lip. A little may fall off, but the straightedge takes more off.

This is analogous to tapping a rotary powder measure while the cavity is open to the hopper, so that more powder enters the cavity before the cavity is turned down (past a solid scraping edge) to dump the powder it contains into the case. Some rotary measures (e.g., Lyman) actually have a weight hinged to the side of the measure to facilitate a uniform "tap."

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Old June 2, 2013, 06:13 PM   #54
pathdoc
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I played around with the "scoop through the powder" and "sink the scoop in the powder" methods tonight. In the interests of speed and ease of reading scales, I used my little Frankford Arsenal digital scale, which is accurate to 0.2 of a grain. I figure this is fine if I'm well away from maximum (which I am; 42 grains for the 174gn bullet; 43gn for the 150gn bullet). I used the 2.8cc scoop that came with my .303 Lee Loader kit, and the expected weight as per the enclosed powder chart was 38.3 grains of Varget.

Pouring some Varget into a bowl to an adequate depth, I scooped 20 scoops using each method. Although this is fairly low, it was dictated by time constraints and the assumption that the shooter with a Lee Loader is going to do no more in one session than sit down with a box of fired cartridges and reload them, so a larger sample size may not be relevant. I zeroed, turned off and recalibrated the scale after each lot of 20. I struck the top flat with a card before dumping each scoop in the pan.

I plugged the numbers into Microsoft Excel (raw data below; apologies for the post length), and got the following number crunches:

"Scoop through the powder" method (weights in grains, of course):

38.4
38.4
38.7
39.4
38.7
38.7
38.0
38.4
39.2
38.4
38.9
38.3
38.9
37.3
38.6
39.2
37.8
38.4
37.8
37.5

Average 38.5gn, St. Dev 0.6, Max 39.4 Min 37.3, Spread 2.1gn.

"Immerse the scoop" method:

38.7
37.3
38.4
37.8
36.9
37.5
38.0
37.3
37.0
38.0
37.8
37.5
38.0
37.3
36.6
37.5
38.6
38.3
38.4
38.4

Average 37.8gn, St Dev. 0.6; Max charge 38.7; Min charge 36.6; spread 2.1

I'm pretty sure I've applied the formulae correctly, but the raw data are there in case anyone thinks my standard deviations and spread of min and max charges are suspiciously identical and wants to recheck them in a stats program (I was certainly surprised!!!).

All this (with a strong caveat for the small sample size) suggests that the scoop-through method provides a charge closer to stated weight, but that there isn't much variation of accuracy between methods.
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Old June 2, 2013, 07:00 PM   #55
Wrangler5
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Out of curiosity - OP, have you bought a scale yet? I see you started your scale thread in April (and got lots of good advice) and this one is more than a week old. They aini't gonna get any cheaper, and a quality beam scale will last you the better part, if not all, of your life. (I've used the RCBS 505 for decades, but the Dillon beam scale is the same thing and usually about $20 cheaper.)

Amazon Prime will get a 505 to you in 2 days with free shipping. Graf's in Mexico, MO sells the Dillon and has free shipping (but not second day for free.)

Dippers are fun to talk about, but really . . .
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Old June 3, 2013, 08:53 AM   #56
SL1
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pathdoc,

In case you don't have enough to do on some rainy day:

How about doing the test one more time, scooping through the powder and tapping the scoop (vertically) on the edge of the powder container before striking the top level with the card?

What I expect you will get is charge weights near the max of the "scoop through" test that you already perfomed, but with a smaller extreme spread over the 20 charges, and thus a higher average, too.

SL1
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Old June 3, 2013, 05:17 PM   #57
pathdoc
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I caught myself tapping as you describe reflexively in both phases of the test. I couldn't tell you how this correlated to weights of the individual charges thrown.

In any case, the next twenty charges I throw are going to be into primed cases, then each one gets a 150 grain bullet tossed on top of it and then it's off to the range as soon as weather and work commitments permit.
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Old June 3, 2013, 08:43 PM   #58
spacecoast
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Good analysis pathdoc. Just to note, scaling those variations to a non-magnum handgun-size dipper (4 grains or so) the variation would be .2-.3 grains, more than consistent enough for plinking. After 18K dips, I would like to think I'm even a little more consistent than that.
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Old June 3, 2013, 10:09 PM   #59
mattL46
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You guys are awesome! @wrangler I have not purchased a new scale yet ( but will!!) actually my current scale has been acting less fussy lately and I've loaded about a box or so of some 22 hornet. ( don't worry I'm very distrusting and checked and checked and checked and rechecked whilst loading) and they did their job just fine. But for safety's sake I will be replacing it once I figure out which road to travel. I'm torn between brands and species if you will! Right now leaning more towards a beam. I actually did some of my own scoop testing and my results were very similar to path docs. Although the dipper immersion yielded slightly more consistent numbers for me and after awhile I could keep it within about .3 every time. No striking slightly heaped and was actually UNDER the weight it was supposed to throw with the particular powder and dipper. I didn't think this thread would gather the attention it has. Sweet! And thank you to all of its contributors!!
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