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Tex S
March 24, 2010, 10:54 PM
I am using a Lee Pro Auto Disk PM. I just bought some N105 and Longshot. Neither one of these powders are listed in the chart that came with my powder measure.

Short of trial and error with my disks, or finding a hollow cube that is exactly 1 cc, how can I find the VMD of these two powders?

rwilson452
March 24, 2010, 11:07 PM
Can't help you with the N105 but 1cc of longshot is 12.1 gr.

can you do the math from there?




I am using a Lee Pro Auto Disk PM. I just bought some N105 and Longshot. Neither one of these powders are listed in the chart that came with my powder measure.

Short of trial and error with my disks, or finding a hollow cube that is exactly 1 cc, how can I find the VMD of these two powders?

Tex S
March 24, 2010, 11:10 PM
Yes, thank you.

Where did you get that information?

Mike Irwin
March 24, 2010, 11:32 PM
It's simple, really.

Take the disk with the hole closest to 1 cc.

Throw several charges, and weigh them.

A little simple math will give you the approximate number of grains per CC.

Tex S
March 24, 2010, 11:38 PM
Yeah, I was looking for a disk that was 1cc, but there wasnt one. I think .93 and 1.07 was the closest?

joneb
March 25, 2010, 12:10 AM
http://www.tacticoolproducts.com/powder.pdf
This may help.

rwilson452
March 25, 2010, 08:05 AM
Yes, thank you.

Where did you get that information?


There is a "slide rule" that comes with a box of Lee dippers.


NOTE: this value will be approximate and is usually on the light side. It's published data and Lee tends to do that to insure you won't get an overcharge.

In the end you will need to fish to the correct hole to get the charge you want. Using the VMD method will get you close.

Mike Irwin
March 25, 2010, 09:03 AM
"Yeah, I was looking for a disk that was 1cc, but there wasnt one. I think .93 and 1.07 was the closest?"

That sounds about right.

So use the .93 disk. You know that's 93% of 1 CC.

Say that gives you 9.3 grains. An additional 7% will give you 0.651 grains, which is close enough to 7 grains to get you to the 1 cc = 10 grains.

Brian Pfleuger
March 25, 2010, 09:25 AM
It is curious why they wouldn't do a 1.0cc disk..... my set has .93 and 1.02

RidgwayCO
March 25, 2010, 10:29 AM
My N105 has a VMD of .0917. YMMV

cc / vmd = grains (or cc / grains = vmd)