Perplexing Powder Drop Issue

[RippinSVT]

Ok guys, so here I am at the bench doing the same caliber change I've done many times before, and I set up my Lee auto-disk powder drop exactly as I always have, and then comes trouble. I switched from 9mm to .357, no big deal, except that when I changed disks to drop a 6.5gr charge of Unique, it was only dropping 5.4gr or so. I took it apart probably 10 times trying to make sure it was filling the cylinder fully, with no change.

The Lee Auto-Disk system has ALWAYS worked for me, so I don't know if that is the problem. My math and my manual state that a .71VMD disk is necessary to drop 6.5gr of Unique, but it flat out won't. I even filled the disk hole manually, off the press, and measured it on two scales, still right at 5.3-5.4gr instead of 6.5gr.


The Unique is question is not an old can, and it has always been stored properly in a cool, dry area like all of my powders. Is it possibly that it could somehow have "dried out" or something? I have never experienced anything like this.


Thanks for the help, and I really hope I'm just making some boneheaded mistake somehow.

 

[ljnowell]

different powders meter differently. One powder measures well in small charges while another measures well in large charges. FWIW when i use 700x in my lee auto disk I always have to go up at LEAST one size larger than the charts show, sometimes two. Lee intentionally built the measure to throw less than it says, supposedly, to save the lives of people who buy one and dont use a scale.

I would step up to another size and throw a good 10-15 charges to get a repeatable weight and see where it takes you. As long as you KNOW the weight of what is coming out, it doesnt matter what disk is there.

 

[RippinSVT]

Ok, we are definately on the same page then. I was just a little confused since it has always been quite accurate for charges up to and exceeding 20 grains of different pistol powders. I'll jump on up a few sizes and see where that takes me...

 

[RippinSVT]

Ok, I tried it again. I had to step up to the .88VMC drop in order to make 6.5gr. That's 3 sizes larger than what the manuals say, which worries me a bit.

 

[ljnowell]

Ok, I tried it again. I had to step up to the .88VMC drop in order to make 6.5gr. That's 3 sizes larger than what the manuals say, which worries me a bit.

Unique is a flake powder like 700x, it doesnt surprise me much. As long as it throws constently, you are good to go.

 

[RippinSVT]

Great, thanks buddy. I was thinking the same thing, but since I haven't used a lot of flake powder in this measure, I figured I'd ere on the side of caution. I appreciate it.

 

[warnerwh]

Lee's Unique data sheet is way off. I use the .88 myself but I only get 6.2 grains of Unique. Anyway always weigh the powder. The Lee sheet is off on pretty much everything I have ever tried. I'm sure they do it for liability reasons. It's always less powder than the sheet says.

 

[RippinSVT]

They seem fairly accurate with small-grained ball powders in smallish charges, but that's about the extent of my experience with the auto-disk. Anything bigger or precision related is done on a separate powder measure.

 

[Walkalong]

I had to step up to the .88VMC drop in order to make 6.5gr. That's 3 sizes larger than what the manuals say, which worries me a bit.

I understand the feeling. Anytime something doesn't seem right, go back and triple check everything, including checking other powders weights where you know what the disk has been throwing.

 

[jfh]

I presume that you have double-checked the accuracy of your scale--have you a set of checkweights?

Jim H.

 

[RippinSVT]

Sure did. I re-cal'd both scales and they said the same thing. I know it is inaccurate, but I could also tell just by shear volume that it wasn't even close to what my bench-meter was throwing at 6.5 grains. Anyway, I tested the load and was decently accurate, and I went back and checked my load logs and it looks like I had some 7.5gr loads in October that shot really well, even though they are hotter than what Lee claims is a "Never Exceed" load at 6.8gr. My Sierra manual lists a lot hotter loads, must be due to the fact that Lee markets a lot to beginner loaders who use dippers and such instead of a scale.

 

[Motownfire]

I use Unique for loading 9MM and .40S&W also. I have found to get the powder charge I want I always have to go up 2 or 3 hole sizes to get the charge I want. It took me a few minutes to figure that out when I started with my Lee Turret Press but now it's not a big deal.

 

[1SOW]

If going up a hole or two is consistent then that's a good fix.

I don't use Unique, but Lee instructions say to use a dowel to tap the auto disc as it fills and as it drops with flake powder. This is primarily for consistancy.

I use a fairly hefty dowel with small rod-shaped powder, and it does drop slightly more when tapped. It's also very consistent.