Is using Lee's vmd chart a reasonable way to calculate case fill

[AJC1]

I'm sure I'm not the first, but I downloaded Lee's vmd chart for powders to compare powder density. The cfe pistol I was loading up seemed more dense than siholloette and unique, and Lee's chart deemed to confirm my inclination. I then wondered if the chart was good enough to reasonably calculate case fill.

 

[Warpiece]

As long as you're going for ballpark generalities, it works. I've tried to do something similar for a different purpose. If you need accurate info, there's just too much variation between lots to trust it.

 

[AJC1]

As long as you're going for ballpark generalities, it works. I've tried to do something similar for a different purpose. If you need accurate info, there's just too much variation between lots to trust it.

Accurate enough to compare with nossler load data on powders not .listed?

 

[Warpiece]

I would think so. Verify a couple of your lots of powder against the table, it'll give you a better idea of what you're dealing with.

 

[sparkyv]

Yes, VMD can be used for a reasonable estimate of case fill, but not accurate enough for full house loads. It's best to measure VMD of each can; yes batch to batch variation is that noticeable, don't ask me how I know.

 

[Hooda Thunkit]

Lee's chart will get you close. I usually start there, but weigh, measure, and calculate the VMD for each lot of powder I use.

It helps if powder is purchased in 8 lb jugs. Or, at least check lot #'s if purchased by the pound.

 

[GeoDudeFlorida]

I'm sure I'm not the first, but I downloaded Lee's vmd chart for powders to compare powder density. The cfe pistol I was loading up seemed more dense than siholloette and unique, and Lee's chart deemed to confirm my inclination. I then wondered if the chart was good enough to reasonably calculate case fill.

Long answer: No, the Lee chart is not accurate or up-to-date. Also, it is very generic and does not account for changes in formula or lot-to-lot variation. I have my own spreadsheet I created for calculating the VMD of each LOT of powders I use. It is within a 1% margin of error, which means when I use that chart to calculate a load, I can count on the volume I throw being within +/-1% of the weight charge expected.

Short answer: It's probably close enough to get you in the ballpark if you just want to know if a load will be compressed or have some headspace.