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Star Reloaders Discussion Forums => Loading Data & Reloading Procedures => Topic started by: johnfreeman on April 26, 2015, 05:45:06 pm

Title: Volume measure density
Post by: johnfreeman on April 26, 2015, 05:45:06 pm
Is Lee's data on VMD the "reference" for calculations of Volume measure density?

I have a number of powder bushings and would like to create a spreadsheet to calculate powder drop weight for the bushings I have. The calculation seems straightforward, but is the Lee data a good reference?

Title: Re: Volume measure density
Post by: rbwillnj on April 26, 2015, 07:48:38 pm
That's what I use.
Title: Re: Volume measure density
Post by: Rolling Stone on April 26, 2015, 10:35:58 pm
I started off trying this. I then bought a Hornady powder measure that has the 1/2" square slide that uses the bushings like my star. I started me a spread sheet.. I made 10 or 15 different size bushings. Then I checked what the bushings threw with each powder I use. Turns out there are only a couple I ever use. The Hornady measure does come in handy when I want to load just a few, or a few dozen cases and don't want to mess up my Star set up. The actual weight and the computed weights were close enough but not exact. Before anyone asks, I haven't up dated this in years, only working off a scribbled up, update of the ones I use.
Title: Re: Volume measure density
Post by: fc60 on April 27, 2015, 10:43:47 am

The Lee chart is a good "reference" as powder lots do vary.

I machined a set of bushings in 0.005cc increments.

Next, I weigh my powder with two or three bushings and calculate the actual VMD and write that number on the powder container.

When changing powder weights, this method will get you within +/- 0.005cc.

For loads you use a lot, just write the number of the bushing last used.

By the way, some powders react to the weather causing slight variations in weight with the same bushing. i.e. rainy day vs. dry sunny day. I load a lot of 32 Wadcutter ammo and I notice it more since I am throwing 1.30-1.80 grains of powder.