I realize how convenient it is to use a dipper for loading, but not having a full set of Lee dippers, I can't relate to "2.5 cc of IMR 4895." Can you say what grain weight that volume equals?Sure, JPG, lets talk about that. Hopefully, the information might be useful to other folks too.
Dippers measure powder by volume and scales measure powder by weight. A single granule of powder may weigh more or less in humid Louisiana than in parched Arizona simply because of humidity issues. Powder is hygroscopic. However, a cc is the same everywhere, even in Texas.
I use both means of measuring powder. I've got the dippers and I've got a couple of scales. I use dippers where it's convenient and scales where it's convenient. I've even been known to weigh the charges I'm dipping, just as a double-check.
The short answer to your question is that the 2.5cc dipper throws a charge of 34.3 grains of IMR 4895. The longer answer is that using a dipper is contingent on consistency in how you use the dipper and consistency in how you strike off the excess powder. I've done some experimenting and depending on how I scoop the powder and how I strike off the excess, dipper weights can vary as much as 2 grains.
Lee's site gives us the proper method of using a powder measure:
With the dipper in hand, push it backwards into a powder reservoir such as a cup and let the powder fall into it from the top. Removing the dipper from the cup should yield a heaping dipper full of powder. With a business card, scrape off the excess so the measure is level.Mr. Lee is kind enough to publish online a lot of information about his products, including a handy .pdf file of the most current dipper capacities. Powders change over time and having the latest chart is a big help sometimes. The link is here.
I've even been known to make my own dippers for specific tasks. I've got one that throws exactly 27.5 grains of IMR 4895, which is a favored cast-bullet load for the .30-30. It's a simple matter to cut down a piece of cartridge brass and solder a handle on it. It may look rough, but when I want to reload some of that ammo, it takes a lot of the work out of handling the powder.
Thanks for reading. I hope I was able to answer your question.
6 comments:
When you scrape the powder off with the business card, do you lead with the edge as if you were cutting the powder off, or following with the edge as if you were using a spatula, on sugar, for instance? Or do you keep it perpendicular? It seems that the second method might get some compression and make the charge heavier than intended.
I keep it perpendicular, but it doesn't matter as long as you do it the same way every time. I use the Lee method Pawpaw posted.
Is there any chart data on standard deviations with the three methods, weighing, dipping and throwing?
No, RD, not that I know about. But there'd be no SD with weighing because they'd all weigh the same. Via careful dipping, the charges with vary ± .1 gr from the mean. Throwing is the same. Keep the hopper full and operate the handle the same for every throw, and you'll get about ± .1 gr from the mean.
Just what I wanted to know, PawPaw. And I've already bookmarked that link on the Lee dippers. It will make a good reference. I keep thinking I'll locate a set of used dippers, just to have on hand. There's bound to be one at any large gun show, even if a dipper or two is missing.
Many thanks.
JPG
Thanks, PawPaw,
Being new to reloading, I really value pointers like this from old hands.
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