Lee pro auto disk problems


March 3, 2010, 04:43 PM
I have a very hard time getting consistent drops from my lee auto disk pro. The 2 powders I use are bullseye and universal. Charges vary with .3 grains consistently and I get an occassional odd ball that may be almsot a whole grain off. This is very different from what I have read most people achieve with it.

I have tried several solutions that dont seem to have made much difference such as.
-keeping the hopper full
-running some graphite powder through the hopper
-wiping down the hopper with a dryer sheet

Are there any other suggestions as to what could be wrong? BTW I am using this with a lee 4 die set on the classic turret. So it is hooked up so that the bullet going into the case activates the charge. The seperate chain included with the kit is not used.

If you enjoyed reading about "Lee pro auto disk problems" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!
March 3, 2010, 05:05 PM
I take it you have that spring setup that returns the disk to the "fill" position as opposed to the chain? I have had great luck with consistency in pistol loads, not so much luck with it throwing the correct "published" amount though. I'd be checking to see that the holes are lining up all the way on the "fill" stroke.

March 3, 2010, 06:03 PM
Make sure you are pushing up enough to get a consistent load. I had that problem before and that's all it is. Are you positive the charge hole is going all the way over the drop tube hole?

March 3, 2010, 06:14 PM
Which disks (cc volume) give you the inconsistent drops?

March 3, 2010, 06:20 PM
all that I have tried for .38s, .40s, and .44s.

I have the disk installed where it is supposed to as best I can tell. Also have tried to micro adjustable charge bar which also doesnt work consistently

March 3, 2010, 06:40 PM
One other thing that can vary the charge a tad is not being consistent on the speed you are operating the press. You want to be consistent so the bit of vibration is the same all of the time.

From what I've read Universal meters well. I use Unique which is a similar burn rate but many people say throws varying charges. My load of 6.2 grains Unique stays with in .1 grain 90% of the time but does get off .2 grains on the low side(6.0) or .1 on the high side or 6.3 grains. The accuracy of this particular load in one of my guns is very accurate. It bothers me saying how accurate loads are because so many people lie on the net. My point here is even with a slight variation of typically .1 grain it does not appear to affect accuracy.

All powder measures will vary charges with various powders, the measures vary on what powders they like so to speak. People who shoot in many handgun competitions will load ammo on a progressive knowing that the powder charge is varying a bit. However these most skilled shooters know it does not hurt anything. Just saying you don't need to worry about a + or - .2 grain variation. Getting nearly a full grain or even half a grain variation is too much. Make sure the bottom of the red reservoir is flush with the top of the charge disk.

There are videos on Lee's site to help set up the powder measures.

March 3, 2010, 07:03 PM
all that I have tried for .38s, .40s, and .44s. I understand the reason of not disclosing the disks you use.

Let us try from the other side. Do you receive the same inconsistency when you actuate and recharge the measure by hand, not by shell and chain/spring? Does the inconsistency goes away when you knock at the measure when the disk is being recharged? Is your press mount solid - i.e. the top of the press does not move when you actuate the lever?

March 3, 2010, 08:48 PM
1. Try checking how tight you have the hopper screwed down. If the screws are too tight, then there can be binding...try minute adjustments to the hopper screws (say 1/16 turn) looser and see if the disk / ACB now starts dispensing the same (plus-or-minus one-tenth grain, two-tenths total variation).

2. During setup, make sure the F lever is inserted into the slot in the Disk / ACB--that can be another not-so-obvious mistake, although it looks like you've troubleshot for that...

3. Helg's advice to look at 'external issues' is good--i.e., a consistent stroke, solid press mounting, and so on.

Jim H.

twice barrel
March 3, 2010, 09:52 PM
I use Universal and have found it meters very consistently but did experience a variation last week. I move the measure between caliber changeouts of my preset dies/turrets. Apparently the O-ring that helps keep everything in alignment once squeezed down had slipped and sagged at one side which was just enough to keep the cylinder from completely extending over the drop tube. I suspect not all of one cylinder was dropping on one charge only to have a little excess drop in the next.

Because it had never done this before I knew something was amiss and it took a bit of searching before I discovered the problem. As soon as I unscrewed the powder measure a little, straightened up the O-ring and rescrewed the measure back down it was fully extending the cylinder and the powder charges threw consistently again.

Something to watch out for,


March 3, 2010, 10:14 PM
Charges vary with .3 grains consistently and I get an occasional odd ball that may be almost a whole grain off.

Are you getting these results from the adjustable charge bar or the auto disks?

My experience has been .2-.3 grain variance and sudden jump of .4+/- variance from the adjustable charge bar (there's been many threads that addresses accurate charge bar use, but if you are new to reloading, I recommend you stick to auto disks for now - they involve proper alignment, tapping of bar, use of inserts, etc.).

Also, make sure your powder pour through die is completely clean and dry "inside" so all the powder is dropped into the case.

Is your auto disk brand new?

If your auto disk is new, I found the silicone wiper at the bottom of the hopper protrudes down a bit and when both brass hopper nuts are tightened (they should be finger tight), it will feel "tight" when you first actuate the auto disk back and forth. It will take a bit for it to break in (get coated in graphite powder), maybe around 50+ cycles with powder in the hopper to throw accurate charges with variance of less than 1/10 grain.

When I setup a new Lee press with auto disk, I don't do anything special to the hopper. I fill the hopper with W231/HP38 as they seem to have the most amount of graphite coating and the silicone wiper bottom surface and auto disk top surface very quickly gets coated with graphite (the dark color on the silicone wiper is good, I don't wipe it clean since the graphite is a dry lubricant).

Try running 20+ cycles (I just dump the powder in the case back in the hopper) and remeasure the charges. If it reduces, you are on the right track.

The charge to charge variance will vary from powder to powder. Some larger flake powder will vary typically around .2-.3 grains no matter what from the auto disk. I use smaller flattened ball powder like W231/HP38 with less than .1 grain variance. Bullseye/Unique should give you similar results.

Hope this helps and let us know how it works out.

If you enjoyed reading about "Lee pro auto disk problems" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!