Progressive loading powder measure quick tip

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spencerhut

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I've been noticing people complaining about inconsistent powder charges from this or that powder measure and for the most part it didn't really strike me as odd since I went through a time when I just could not get my powder measure to perform. But then it struck me, I had learned something the hard way and forgotten I ever learned it. Now to pass it on in case you have not learned this lesson.

When you setup your press for a run you fill the powder measure up and cycle it a 10+ times to get the powder settled. Single stage or progressive this preparation is the same. Then you take the pan from your scale and drop and check a few charges with the scale and adjust the measure as needed until you get the charge you want. On a single stage press operation this is exactly the right way to do it. On a progressive there is a bit more going on we have to take into account. If we want a stable charge to be thrown with a progressive press we need to take a few more steps.

After setting the powder measure as above with the single stage method you put your first case in the press and size, prime and charge it with powder. But when you check the powder charge it will be off by more than a .1 of a grain, maybe it's off by .5 grains or more. Why? Well depending on the press you are using there are different reasons why. The important thing to remember is checking powder on a progressive press must be done with the press in operation to get a true result. Using the pan from your scale and just dropping a powder charge to check it on a progressive is the wrong way to get an accurate result. Checking in this "single stage" manner while operating a progressive press could result in a high or low or simply inconsistent charge being displayed on the scale. Adjusting the powder drop using the "single stage" method of dropping a powder charge in the pan and adjusting on a progressive will lead to frustration.

Many (most) of you probably already know this and practice it, check charge weight with a primed case while operating the press with the same cadence and as you would when loading at your normal speed.
There is no other way to assure a correct charge is being dropped.
 
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