Variations in Lee's autodisk and VMD

[ghbucky]

Am I the only one to notice the pretty big discrepancy between the formula that Lee publishes using VMD and the actual reality of powder drops?

Looking at the chart Lee puts out I should use the .34cc cavity to get close to 3.9gr of Power Pistol.

But, I just got done testing which cavity it took to drop 3.9gr and I had to go up to the .40cc cavity.

Do different lots of the same powder have that big a variation?

[nhyrum]

After dealing with loading shotshell with bushings and NEVER getting the advertised weight, I vowed to never again I've pure set volume measuring. I'm not surprised the auto disk is that way. One of the reasons I never got one and always used the auto drum. Which I had 5 of at one point

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[jetinteriorguy]

Different lots of powder and how they are stored all have an affect on the VLD. Lee’s charts are just approximations, not exact, mainly they give you an idea where to start but always always check with a good scale first.

[Unclenick]

If you go to Western Powder's website (for as long as it remains available, now that Hodgdon has bought the distribution rights for their Ramshot and Accurate powder lines) and click on the powders, they show bulk density varies from ±2.2% to ±5.6% (an 11.2% range), so, yes it can vary quite a bit.

[higgite]

Am I the only one to notice the pretty big discrepancy between the formula that Lee publishes using VMD and the actual reality of powder drops?

Not by a long shot. (Pardon the pun) In fact, I'd say that anyone who didn't notice it just isn't paying attention. Lee has lawyers like everyone else. They would rather you be underpowered and blame it on them than blow your gun up, losing an eye or a finger, and blame it on them.

[ghbucky]

One of the reasons I never got one and always used the auto drum. Which I had 5 of at one point

Well, I just ordered my first one

[sparkyv]

I see what you did there.

Originally Posted by higgite

Not by a long shot.

[jetinteriorguy]

Originally Posted by ghbucky

Well, I just ordered my first one

You’ll like it. I have a couple and they work good on my Lee Classic Cast turret press.

[berettaprofessor]

I've got a half dozen Auto Disks and never did understand why people think they don't throw accurately....mine is as consistent as my scales are, almost never even 0.1 off....and I use a number of powders through them, but mostly small grain. W231, CFE223 CFEBLK, AA#2, Trail Boss, CFE Pistol. No issues. That autoloading off the case mouth expansion die is pretty hard to beat.

Am I the only one to notice the pretty big discrepancy between the formula that Lee publishes using VMD and the actual reality of powder drops?

No, but consider the chart an approximation and fine-tune from there. It will be consistent within the same bottle/lot.

[higgite]

Originally Posted by berettaprofessor

I've got a half dozen Auto Disks and never did understand why people think they don't throw accurately...

I believe some think if it doesn't hit the numbers on the VMD chart precisely, then it's not an accurate powder measure. The one I had never hit the VMD number, but like yours, it was consistently within 0.1 grain of my target load with W231.

[Aguila Blanca]

Lee's chart for the Autodisk says aperture #49 will drop 5.3 grains of Winchester 231. Mine drops 5.3 grains. Once in awhile it may hit 5.2but, for the most part, it's boringly consistent.

[ghbucky]

The frustration comes with having to try a cavity, shut off the powder, drain the remaining, take it apart, try a new cavity... rinse and repeat.

It is consistent once you find out which cavity gives you the drop you want. No argument. Just frustrating finding it.

[mikejonestkd]

The frustration comes with having to try a cavity, shut off the powder, drain the remaining, take it apart, try a new cavity... rinse and repeat.

A pen and paper will help. Write down the CCs and the powder weight for a particular load, that way you only have to do it one time to find the desired powder weight.

Lee's chart for the Autodisk says aperture #49 will drop 5.3 grains of Winchester 231. Mine drops 5.3 grains. Once in awhile it may hit 5.2but, for the most part, it's boringly consistent.

Mine too -.49CC and 5.3 gr win 231 is my default charge for .45ACP and 230 gr RN. Its perfect every time.

[kmw1954]

I don't even look at the printed chart. When I did some were close others weren't even close. I have 4 powders I use regularly and have printed my own chart from actual drops. I have found variations even from lot to lot of the same powders.

With my pistol loads I now mark my labels with both the powder weight and disk number when I use the disks.

[noylj]

Wow, rejecting something because Lee's perfect packing bulk density didn't match your findings? It's just an approximations.
Lee always leans towards safety over data accuracy.
I simply record what I get and calculate the VMD from that and use it from then on, though powder lots do make some difference.
Powder VMD (cc/gr) Bulk Density gr/cc
231/HP38 0.09846 10.156
540/HS6 0.07093 14.099
AA2 0.08496 11.770
AA5 0.06832 14.637
Clays 0.15171 6.591
Herco 0.12854 7.780
Power Pistol 0.09047 11.053
Red Dot 0.15657 6.387
Trail Boss 0.23006 4.347
Unique 0.12667 7.895

[TruthTellers]

No two things are ever exactly the same, that's why it's important to check what YOUR equipment gives you, not what the books and manuals approximate.

I've only used the Auto Disk for AA#9 so far and while there is a decent amount of leakage, the throws are spot on. I had trouble with this fine powder in the Auto Drum and other measures, but no issue in the Auto Disk.

I started off with the Auto Drum and liked it, but have been having issues with it lately and am finding that I don't care for it as much now.

[Twinsig]

I stumbled upon a web thread discussing the leaky auto drum where one participant mentioned reducing the "slop" by lightly sanding (level surface) the reservoir mount.
Be careful though, doesn't take much, and it did reduce leakage.

[TailGator]

I experienced the underweight throws, too. I feel certain that it's like an earlier post said, that Lee is erring on the side of safety. Using the chart won't give you squibs, but it will seldom give you the indicated weight, either. Keep a log and the problem will be solved. The Autodisk has been reasonably consistent for me, good enough for plinking handgun loads, once I zero in on the right orifice.

[5whiskey]

I have one of the old auto disks. The hopper now has machine bolts epoxied in it and I tighten it down from underneath with nuts. I’ve filed the top of the frame to make the hopper fit tight so it doesn’t leak. I’ve noticed my powder throws are pretty much in line with the lee chart. Maybe they changed something between the old one and new one (volume is volume though, I don’t know why it would change). It meters hs6 to the exact the tenth grain, every time. It does ok with flake powders like 700x. It’s why I keep it. And at any rate, it’s made far more pistol rounds than a 30 dollar piece of gear should have to...

[jetinteriorguy]

Originally Posted by TailGator

I experienced the underweight throws, too. I feel certain that it's like an earlier post said, that Lee is erring on the side of safety. Using the chart won't give you squibs, but it will seldom give you the indicated weight, either. Keep a log and the problem will be solved. The Autodisk has been reasonably consistent for me, good enough for plinking handgun loads, once I zero in on the right orifice.

You can customize the cavities with a tapered reamer. I just find the closest cavity that’s under the weight I need and then carefully ream it until it throws what I want based on working up loads with my drum measure. Then I just mark them and I’m good to go. I do this with all my favorite pistol loads.