Lee Auto Drum quirk

[sghart3578]

Hello friends,

I guess there is an upside to a cold, rainy day in the garage with the house to yourself.

I had the chance to look into some odd behavior with my Lee Auto Drum powder measure.

I really like this powder measure. It seems like I always need a powder charge that falls between the fixed cavities provided with the Pro Auto Disk kit so the adjustable cavity on the Auto Drum is right up my alley.

When my Auto Drum is mounted on a fixed stand or a fixed press like my Classic Cast single stage press the powder drops are accurate and repeatable. So much so that I dropped from checking every round to every 5 rounds.

But when I mounted the Auto Drum on my Classic Turret press things went hinky.

Example: I would set the measure to drop 12.8 gr of 2400 on my 357 mag turret. It was rock solid as usual.

But then I started actually loading rounds. The charge had increased .5 gr to 13.3 gr! I dropped the powder back into the hopper and, without advancing the turret, I dropped another charge. It was back to 12.8 gr.

I continued on. I finished that cartridge and started another. Sure enough the charge had increased to 13.3 gr!

I figured that what was happening was the rotation of the turret, the sudden stop and start, etc. was causing some settling in the hopper and cavity. Being a redneck engineer I experimented by setting my desired charge weight .5 gr light intentionally.

When in the fixed position I started dropping 12.3 gr of 2400, time after time. But when I started advancing the turret I got my desired 12.8 gr of powder over and over.

I tried this experiment with W296, A #7 and A #9. All acted the same way. Just the amount of initial offset was different. The A #7 was .3 gr off for example.

If you are having similar inconsistencies with your Auto Drum check this method out. Then again it may just be my powder measure.

I hope this helps someone. And now the sun is starting to come out here in N California.


Steve

[trails4u]

Good observation, Steve. I've had the same experience and adjusted for it by setting my drums by weight after rotating the turret as I would when loading. After that....the thing is honestly scary accurate and repeatable for what it is! As with anything else we do, consistency in process usually wins the day. If for some reason I lose rhythm and the movement of the measure might have been different, I just dump that charge back in the hopper and proceed....

[Conditor22]

My guess, Turret, and progressive presses have more vibration and settle the powder more in the powder measure.

I calibrate the powder drop on my progressive and keep the motion/rhythm the same. IF I have to vary the motion/rhythm I pull that case and toss the powder back in the hopper

[Livin_cincy]

The powder will settle from indexing the press.
So you need to 'bounce' thru all of the die stations to get a repeatable throw.

I suspect many people never came across it if they are loading on the low end of the load data.

Great post !

[country gent]

Not only the vibration of rotating the turret but the vibrations of the press stroke will settle the powder into the cavity. I have done some testing with progressives and press operated measures ( never the Lees though). I have found the press operated measures tend to be more consistent in charge weights. 1) is the consistent mounting and vibration pattern of the press operating, 2) The more constant operation of the measure with the press stroke. Almost all measure depend on consistent operation for good results. Speed of operation, bumps top and bottom, solid mounting, and last is consistent powder level in the hopper.

[jetinteriorguy]

Yup, this is why I've always set mine while using it in the Turret and not on a fixed press. I think this is one of the reasons this powder measure works so well for throwing very consistent loads. I use mine to load .38 sp, .357 mag, .41 mag, 9mm, .223, and 7.62x39 with amazing results in my Classic Turret.

[kmw1954]

My experience with the Auto drum used on a turret press and a Pro1000 while using AA#2, AA#5, HP-38 and Ramshot Silhouette. When I change powder I but a shell into the press and rotate it under the measure. Raise it and throw a charge, lower it just enough to clear the dies, remove the case and weigh the charge. Dump the charge and I repeat this until I get to the target weight. I also make adjustments while the ram is raised and the measure is in the dumped position and empty. With these powders I haven't noticed a change once I start fully running the press. Though when I have seen a change it has always been to the light side and not heavier than the target weight.

[Kenstone]

Interesting topic here...

Something you might want to try
I guy on ebay sells powder measure weights, that I found interesting, kind of the opposite of baffles.
https://www.ebay.com/sch/Powder-Meas...ZTp&_ssn=rrpmi

So being a cheap butted reloader, I made one out of wood to test the theory.
I'll confess that I used/use this weight in a Lee deluxe disk measure though.
My test was 10 throws of 231, with and without the weight, and the hopper about half full.
I weighed both, and the weighted powder weighed somewhat more but not by a lot.
Then I did 10 throws, ten times, both with and without the weight to check consistency (a combined total of 200 throws).
The 10 throws with the weight had a greater consistency than the group without the weight.
I recorded all this data at the time but tossed it once I had a definitive conclusion, so I can't give specific numbers here.
Although that weight has changed some, I still use that crude weight,

[OS OK]

Vibration does this on all the press mounted throws to some extent or another.
The only way around the 'settling within the metering hole' is to leave your dispenser in the 'delivered' position as it rides the turret. Only problem there is the auto dispensers that will not stay in the thrown position.
Even the auto throw on a press like my LnL will throw heavy because of the first two pulls as the throw is settling as it waits for a case to come under it in the first shell plate loading of the progressive. After that it too responds the same way.

Even trying to get a consistent COAL setting on a progressive will change when the entire shell plate is loaded vs when it is not.

Your just starting to note some of the little 'subtle' things going on while reloading...congratulations, 90% of the rest of the fellas will never see it.