Lee VMD numbers


July 13, 2008, 10:40 PM
I'm using the Lee Pro Auto Disk to measure powder. I looked at the chart to select the proper disk, but when I threw the powder, it was way under the number of grains specified in the recipe when I weighed it. I threw about 6 loads just to make sure I had everything settled in. So, I went up a size on the disk to get the proper weight of powder. I assume this was the appropriate step to take. Was it?

If you enjoyed reading about "Lee VMD numbers" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!
July 13, 2008, 10:46 PM
Yes, as long as you weigh the charge(as you did)to make sure it is what you want. You are not the only person to find the charge weights are lower than stated. It could very well be a CYA thing IMHO. Just make sure you are getting the charge you want and that you make a note of what adjustment you had to make so you will know next time you try to duplicate the load.

July 13, 2008, 11:03 PM
I use that measure myself and can say it is pretty consistant. Problem is that it doesn't always throw what the chart says. Most of the time I can get get real close and just trickle the rest. Of coarse some powders just don't meter well.

July 13, 2008, 11:09 PM
Once I got the correct disk, it was very consistent. I weighed the first 5 loads, then every fifth load after that. I also developed a procedure to prevent double charges. After I hand prime a case, I put the primed cased in the loading tray primer UP. This allows me to inspect the primers. Then, I will only load cases that were in the tray primer UP. I will not load a case that is primer down. That way, I know the case is empty when I pick it up. I still go through the additional step of inspecting all cases to ensure the amount of powder is roughly equal, but this procedure gives me extra comfort. I like my guns, and my fingers, too much to do otherwise.

evan price
July 14, 2008, 12:17 AM
Lee says, right in the manual, the disks are intended to throw light. I personally ream out my discs to throw exactly what I want.
Once you get the disc size you want, mine are usually +0/-.1 grain in accuracy, or, VERY accurate.

July 14, 2008, 01:39 PM
This comes up every so often...

Think about the problem from Lee's point of view. They have to worry about the natural and unavoidable variation in weight per volume of all the different reloading powders. I've read that a powder's vmd can vary as much as 10%. I therefore suspect that Lee's charts are computed on the conservative side of the allowable variation, to protect those reloaders foolish enough to just use a powder charge based on the charts, and not taking the time to actually weigh them...

Luke G
July 14, 2008, 02:50 PM
I have noticed the same light loads with Unique and H4895 using both the auto disks and the dippers. However they are very consistant. So yes, moving up a size or even reaming out the holes like one poster did will fix the problem, as long as you check your load with a scale (which you did).

July 14, 2008, 02:57 PM
Yep, the load was about 10% too light. Thanks guys, very helpful.

If you enjoyed reading about "Lee VMD numbers" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!