Lee Powder Measure

[schotzfyred]

My Lee powder measure is throwing charges of 8 gr Unique when it should be throwing 10 gr per the VMD numbers from Lee.
I know the VMD values are approximate per LEE, but 20% seems there is something wrong with the number or my measure.
When I adjusted the measure for 11 gr, the measure threw 9.1 gr
My scale is spot on...verified 3 times during this trial.

 

[Jimster]

I’m no expert but are you talking about the Lee Disc or Drum measure?

 

[schotzfyred]

Delete

 

[jaguarxk120]

A powder measure is set by using a scale.
Note the reference numbers on the measure are just a starting point.

 

[schotzfyred]

Delete

 

[badkarmamib]

I am using the Lee PPM as well. I find it very repeatable, but nowhere near what the included VMD numbers are. I believe that there is a disclaimer on the sheet, to use the VMD as a starting point, but to verify with a scale. To save you some of my troubles, make sure you calibrate your scale each time you move it . Check weights are good, but I use a brand new dime, supposed to be 35.004 grains. Trust your calibrated scale more than a "guideline sheet", be safe, and have fun!

Also, your 20% low findings mirror my own. I am all for erring on the side of caution, but that seemed a little ridiculous to me. I keep the micrometer reading on my index card for each load, set the PPM to it, and verify the throw.

 

[splattergun]

Many of us use the Lee PPM. It is a good, repeatable scale, once you learn to use it correctly. We've all quickly learned to not rely on the VMD values. We tossed it into the back of the cabinet or into the trash and use our scales exclusively. Myself included. Use your scale. Set aside the VMD.

 

[schotzfyred]

Delete

 

[Hokie_PhD]

Ive found great consistency with some powders and maddening inconsistencies with others using the PPM. Like others said, if the powder is consistent I just set it via tests with the scale.

 

[snakeye]

Exactly! what splattergun said

 

[wrench459]

With my Mr. Green jeans powder drop.
I'll need to get into a certain rhythm.
Tick-tock

 

[kcofohio]

It's called the LEE perfect powder measure. Has a rotor with a metering chamber assembly.

Even with the Pro-Disk, I never found the VMD to line up with the chart. Usually about a 1/2 a grain off on the light side. Could be that those numbers use powders more settled in? But it does give a close setup point to start.

 

[Hondo 60]

I have 4 PMs (2 of which are Lee) and NONE of them throw the "stated" weight.
I don't think there's anything wrong.

But ... that's easy to say from my chair & keyboard.

YOU are the safety measure needed.

Good Luck & please stay safe.

 

[CZ9shooter]

I have never even bothered to look at the numbers on my Perfect Powder Measure. Every time I use it I just dial it with my beam scale and start loading ammo. Once it is set it throws very consistently.

 

[Walkalong]

As posted, forget what Lee says a certain setting should throw, set it up with your scale and be happy.

 

[daboone]

Actually the PPM (as is the newer upgraded model, the Deluxe) is consistent and reliable using VDM values. The caveat is you must calculate the VDM for the specific lot of powder you're using. The values listed in the Lee manuals were for the lots # they used. Thus they are only appropriate. Calculating VDM is included in the instructions.

 

[ATLDave]

The Lee volumetric estimates are garbage. They have been far, far under on every powder I have thrown with my Auto-Disk. You can use them to start the process of closing in on the right volume total to get your desired weight, but do NOT expect them to be correct. They almost never are.

 

[thomas15]

Have you verified your scale with proper check weights?

 

[Walkalong]

The caveat is you must calculate the VDM for the specific lot of powder you're using. The values listed in the Lee manuals were for the lots # they used. Thus they are only appropriate.

Yep, and since we still have to weigh and verify, use the scale, forget the VDM numbers.

 

[mdi]

I believe the numbers on the thimble are relative and not accurate VMD numbers. I don't try to dial in my PPM by the thimble numbers, I use my scale and for a couple loads, I record the numbers on the thimble for future use. Also, the same powder can vary in "volume measurements to weight" for a few reasons the main being humidity. Powder in a high humidity area will weigh more per cc than the same powder in a dry climate. I also believe lot to lot variations also affect weight/volume ratios...

 

[sparkyv]

you must calculate the VDM for the specific lot of powder you're using. The values listed in the Lee manuals were for the lots # they used.

Exactly! And it must be done again when a new lot of the same powder is obtained. Once the powder has been calibrated, the PPM works very, very well. It provides reliable performance and is very repeatable.

 

[daboone]

The advantage of the Lee Classic or the newer Deluxe is the seriously upgraded micrometer, for those of us who calculate the VMD is the updated micrometer. It is accurate and repeatable. Thus making the time spent fiddling around finding the precise charge a thing of the past. They are the only PMs the market today that allow you to directly dial in a volume of powder with out going thru a series of adjustments once the actual VMD is determined. Of course common sense requires verification on a scale. But the scales uses is reduced because 98% of the time it's on the money.

 

[Dudedog]

Some listed VMD numbers are quite close some are not.
Different powder lots will have different VMDs as well.
Most of Lees VMD numbers tend to be high which results in a lighter charge than expected. (better to light than to heavy in their thinking which is reasonable choice)
They list Unique at
UNIQUE .1092
When I did some tests to get my working VMD of my lot of Unique I got a number around 0.132.
I was looking at smaller charges so I used a .43 disk, a .57 disk and a .66 disk, threw charges from each, averaged charges weight computed the VMD for that disk and then averaged the VMDs.
(still weighed the charge to see what I was getting but it gives you an estimate of what you will get)
VMD=cc/gr or of course gr=cc/VMD
Using Lees VMD of .1092 a 1.09cc disk would throw about 10gr, using my computed VMD it would be lighter around 8.3gr.
I did this for powders I used a lot when I was using my Lee Pro Disk.
Out of all the powders I tried I think Lee's VMD for Unique was off the most.
Universal for example was pretty close, for it they list .1099 my lots were about .11
In the end all that really matters is what a disk throws, VMD just gives you an idea of what a disk will throw and whether a certain powder is "dense" or "fluffy"

 

[berettaprofessor]

If you use a specific powder for several calibers (like W231), and you have the weights generated on a Lee AutoDisc for two or more different cavities, then you can make a graph (like the one below) and predict what other cavities will throw with good accuracy. That'll save time when you're adding another load and need to predict the closest cavity.

 

[denton]

Coins are not very good check weights. I've done consulting work for the US Mint, and have seen the variation in coin weights. Now if you get a new coin and check on a known scale, you can use that.