Checking Thrown Powder Charges

[huntinaz]

I've been meaning to post this for awhile--since like 4 years ago when I first started using Unique powder. I discovered that what the Lee chart says the auto disk powder measure should throw isn't always what it actually throws. A slight variation is to be expected perhaps, but what I have found is that with Unique the variation averages more than a whole grain. As stated in an earlier thread, all other powders I've tried meter within 0.1gr of what is published in the Lee chart. The point of this thread is neither to bash Unique powder or Lee equipment; I am happy with both. Mostly it is to show what variations can happen, and that it is a good idea to make sure your powder thrower is working as expected before you crank out a bunch of ammo.

Here is what I have for Unique charges. Not as bad as I remembered, but still worth noting. As I mentioned, every other powder I've tried is within 0.1gr of what Lee states it should be.

Lee Auto Disk Measure
Hole size Lee Prediction (gr) Actual charge thrown (gr)
.57 5.2 4.4
.61 5.6 4.7
.76 7.0 5.9
.88 8.1 6.9
.95 8.7 7.5
1.02 9.3 8.0
1.09 10.0 8.3
1.18 10.8 8.9
1.26 11.5 9.4, 9.8*

*The first few times I used the 1.26 hole it was throwing 9.4 +/- 0.2gr. Lately, and for quite awhile it throws between 9.4 and 9.8, with the mode being 9.7 and 9.8 gr. I've never bought a new pound of Unique, I respond to craigslist adds and such and have bought a few large lots of reloading stuff. I almost always end up with a partial container of Unique. The first jug I ever bought was an older can, so perhaps that can explain why the measure threw 9.4gr at first, and now throws closer to 9.8gr. I don't remember how old the can was but may have been "old" vs "new" Unique.

So take it as you will, standard practice for many but I was just starting when I noticed this. At the time I had tried Titegroup, Clays and Bullseye and all charges matched up. I remember wondering how important checking with the scale really was. Then I tried Unique and couldn't believe it. I checked the measure over and over and made sure my scale was calibrated, but it is consistent. That's what she throws. My worry was that it would start throwing the posted charge one time so I weighed every charge for a couple hundred rounds. I still weigh more than usual, probably 1 in 3 charges. I mostly only shoot Unique in 45 Colt anymore, and only use the 1.18 and 1.26 depending on what bullet I'm shooting.

Anybody else had this issue? Surely other people are using Unique with a Lee Auto Disk...

[PawPaw]

Unique is notorious for not metering well, but lots of us, myself included, use it anyway. Why? Well, it works. Most of us use it in applications where an additional half-grain isn't going to make any difference. Yeah, it doesn't meter well, but we've accepted that. It's a remarkably versatile powder and I use a lot of it, but I make sure that I'm not running up against the top of the load chart.

[WWWJD]

I think generally speaking, you can expect variation with the autodisk regardless of powder type. Some are more problematic than others. I use the double disk kit with stick powders. I consider the chart provided by Lee as just a learning tool only; it's not quite right (at least for large volumes of stick).

What I wound up doing is setting up a set of disks, dropping and measuring 20 charges on the scale. I logged this in excel to see what the variations were. Depending on the disk combination, the spread would be better or worse on average. I don't have the spreadsheet here at the office to show you, but the random swings in charge weight seem to be manageable. I was hoping for better, just so I wouldn't feel like I have to trickle every charge.

I haven't loaded for pistol, but I suspect you'd see the same performance variables for the smaller stuff with ball and flake (I'm playing in the 40-46gr ranges).

[huntinaz]

My experience has been that the Lee chart correlates extremely well for every other powder I've tried, which have all been pistol powders. Stuff I've tried for sure:

Titegroup
HP38/W231
Clays
Bullseye
700x

All of these powders are thrown within 0.1gr of what is predicted in the Lee chart.

Unique is notorious for not metering well, but lots of us, myself included, use it anyway. Why? Well, it works. Most of us use it in applications where an additional half-grain isn't going to make any difference. Yeah, it doesn't meter well, but we've accepted that. It's a remarkably versatile powder and I use a lot of it, but I make sure that I'm not running up against the top of the load chart.

Yeah, I use it too. Cause it works. Plus it smells good. And I'm not forcing the pressure curve. And if I am loading at max pressures, I weigh every charge. I'm not talking about the metering from charge to charge, but the fact that it doesn't match well with what Lee says the measure is supposed to throw.

It's no hill for a stepper, as they say. I know what my measure throws and it's all I load in 45 Colt. I'm not trying to cause any beef with Unique fans. Just pointing something out, and curious if anyone else has had this particular issue.

[jmortimer]

This dead horse was just beat, the thread closed after much discussion, and as the mod noted, "no minds have been changed." I will continue to use Unique but some won't. To each his own.

[totaldla]

I usually throw and measure a string of 20 when starting with a new powder just to get an idea. And when I setup my Dillon I will throw and measure a string of 10 just to make sure that I have a handle on the press behavior. Powder dispenser variation is just one of the variables in my reloading process and I get a final view on it from my chronograph.

[dickttx]

The chart with the Pro Auto Disk cannot possibly be correct for all the powders and weights listed. As they say in the instructions, it is based on the weight of a cc of a particular lot, and is a starting place only. Other powder measures I have had were all more of a guess than the PAD when trying to set them for a particular charge.
I have only used HP38 and Unique in mine and neither are within one grain of the chart for a particular disk hole. When you do find the hole for the load you want, it is by far the most consistent measure I have ever used.

[huntinaz]

The chart with the Pro Auto Disk cannot possibly be correct for all the powders and weights listed

Sure not exactly, but over a grain seems kinda ridiculous. All the holes are should be the same size from set to set, they should all throw very similar charges and they should have a much closer guestimate than 1+ grains.

HP 38 for me has thrown as expected, within .1gr or what is predicted.

The interesting thing to me is that if the holes were drilled wrong, all powders should be off, not just one. So I think it's important to check and make sure you know what your measure is doing before proceeding. Since all the other 5 powders I've tried have been so close, I was very surprised to see this much variation. Also, I've tried multiple lot numbers in W231, Titegroup and Bullseye and if there is variation between lot numbers I've yet to notice it.

I've also used multiple lot numbers of Unique. Cracked open a fresh can yesterday and it measured just as I had recorded with the first can of Unique I ever used. So I have not noticed much variation lot to lot regardless of powder.

When you do find the hole for the load you want, it is by far the most consistent measure I have ever used.

Yeah I like it, it's been consistent for me. It's the only measure I've ever used so I can't compare. Thanks for the reply, was just gonna let this one go since it seemed most people just wanted to argue more about Unique metering consistenty, which was not at all what I wanted to discuss.

I would be curious to see how the charges of Unique your measure throws correlate with mine, if you have them written down.

[dacaur]

When I was using unique for my 9mm loads I used .66 for 5.4gr with 115gr bullets. When I switched to 124gr bullets I charged to the .57 hole, and it threw an average of about 4.5gr. Charges would vary anywhere from 4.3-4.7gr. I dont remember the exact variance with the .66 hole, I just remember being surprised that it thew such a low charge when I set it up at first with the .61 hole aiming for around 5.5gr

Currently I'm using power pistol instead. Using the .49cc cavity gives me 5.3gr (124grbullet, 9mm), the chart says 5.5. I also use the .34 cavity for 100gr .380 rounds, which drops 3.6gr, the chart says 3.8.

The disk cavity listed on the lee chart will ALWAYS drop a lower charge than what the chart says, they do that on purpose because they know there are morons out there that will look at the chart, and start loading without weighing anything, so there is a "buffer" to keep their loads within safe limits..... I have a feeling they give a bigger "buffer" for powders that dont meter as consistently. Hence a .7ish gr "buffer" for unique, and only a .2gr "buffer" for power pistol.

[huntinaz]

I have a feeling they give a bigger "buffer" for powders that dont meter as consistently.

That makes sense to me.

Also, I screwed up my chart a little in my original post. .66 throws 5.5gr for me, and .71 throws 5.9gr (not the .76 as I stated in my original thread). My error, I don't have a reading for the .76 hole.

So our data seems to jive.

[PA-Joe]

Each lot of powder has a different density and therefore you should never rely on the tables. Every time you change powder batches you have to create a new table. This occurs with any volume type measure even the LEE Spoons.

[Dave R]

I agree, Unique is farther off the Autodisk chart than other powders. And doesn't meter as well.

HOWEVER, I have found that, if I "drum" the side of the powder cannister before throwing the charge, it gets more consistent. Settles the charge a bit, I believe.

So I use it with the Autodisk and get reasonably good results.