Pro Auto-Disk Inaccuracy?

[cobaltLoader]

Hi,

I am New to the forum and to reloading as well. I just set up a Classic Turret with a Pro Auto-Disc, and I have been having a hard time getting the recommended disk to measure correctly. I am loading 45 ACP and have been running powder through it all morning to try and get it lubricated(coated is I guess more accurate), but the disk that lee recommends is coming up way short still. I am using IMR 800X powder and the recommended .66 hole on the disk. I am supposed to have a start grain of 6.3, but I am only getting between 5.5 and 5.9 on a regular basis. I am running a throw away shell through all of the dies in order to have the powder settle, but I am still not close to the start grain. I have jumped up to the next bigger hole, the .71 is giving me weights starting at 6.2 up to 6.8.

Anyway, I am a bit conflicted, and am not sure what I should do moving forward. As the never exceed is 7.0 and I am getting so close with the .71 disk, but nowhere near with the recommended .66. Any suggestions are greatly welcome.

Thanks

[62chevy]

I never get that big a variation with Bullseye but every powder is different. A lot depends on if the powder is ball, flack or stick type powder with stick being the most fussy for metering and ball maybe the easiest. How you run the press can make a difference too Steady consistent movement helps but the powder may be the biggest problem as I have never used your powder some else will have to help you with that.

Hope this helps.

[cobaltLoader]

I never get that big a variation with Bullseye but every powder is different. A lot depends on if the powder is ball, flack or stick type powder with stick being the most fussy for metering and ball maybe the easiest. How you run the press can make a difference too Steady consistent movement helps but the powder may be the biggest problem as I have never used your powder some else will have to help you with that.

Hope this helps.

Thanks Chevy. Am I going to see a noticeable difference between 6.3 and say 6.8 grains? If not, I will just keep using the .71 hole and keep an eye on the weight and make sure I don't go over like 6.9.

[daboone]

With Auto Disks what the listed # is stated to drop in grains for a specific powder is rarely what it drops. But it is usually quite consistent for small grained powders. Some large flake and long extruded powders aren't well matched for the Auto Disk. You may have to use the next higher or lower. +/- .1 or .2 grains isn't going to be a big deal unless it's a very small volume case or your pushing the max load.

[62chevy]

Auto Disk Metering Consistency

When selecting a powder to use in a powder measure it is important to consider the shape of the particles called granules. All powder measures achieve their drop weight by filling a cavity or an adjustable vile having a quantifiable volume with powder. The physical shape of the granules are a part of the manufacturing process and due to their physical shape some granules will fill the powder measure more consistently than others. The following is a list of common powder granule shapes in the order of best to worst for metering in a powder measure.

BALL POWDER consists of spherical granules that are normally small in size. This type of powder meters very well.



FLATTENED BALL POWDER is very similar to ball powder but is flattened slightly. This type of powder behaves almost identically to ball powder.



EXTRUDED POWDER or Stick Powder has granules that are shaped like small extruded cylinders. One issue that can arise with this shape is the powder measure cutting the sticks into different lengths which will lead to slight inconsistency.



FLAKE POWDER has granules that are shaped like tiny disks. Flake powder is the most difficult to meter correctly due to the fact that it can “stack up” and/or "bridge" in the powder measure making it less uniform when metering.



Make sure that when measuring charges thrown by the Auto Disk measure, that it is done out of the normal loading sequence. It is important that the measure work consistently in the amount of force used to move the disk to the drop hole and return. This is accomplished through consistent press lever operation every time.

It is also very important to ensure that the Auto Disk measure is seated securely into the Powder Through Expanding Die which must also be properly adjusted. This information can be found on this FAQ under "Die Questions" and then "Powder Through Expander Adjustment". If you are using a chain return system, it must be adjusted properly. This ensures that the disk moves the same amount each and every time the lever is operated. Proper adjustment of the bead chain can be found on this FAQ under "Powder Handling" and "Auto Disk Chain Attachment".

You may want to "condition" the measure by either using powdered graphite on the disks or running the equivalent of a pound of powder through the measure. If you find that inconsistencies still exist, you may want to wash the disks in warm soapy water, rinse and let air dry. This should help eliminate any static that may have been present.

Lastly, some powders do not meter well. Unique powder is one example that meters with "casual uniformity". You may find the same symptom with small flake powder in small quantities.

This was sent in an email from Titan Reloading.

[cobaltLoader]

Thanks guys, very helpful, looks like I choose the most difficult to measure with my first batch I am gonna do 50 rounds, measuring each, then range test them. I'll let you know how it went.

[Ranch Dog]

Welcome to the forum cobaltLoader! Seem like you are getting the help you need. All that I can add is that specific gravity of any given powder can vary quite a bit from it's spec. It is best to determine the VDM of your given lot of powder and write it on the jug.

This will help you calculate a cavity for your Auto-Disk that delivers the charge you need to work with.

[cobaltLoader]

Welcome to the forum cobaltLoader! Seem like you are getting the help you need. All that I can add is that specific gravity of any given powder can vary quite a bit from it's spec. It is best to determine the VDM of your given lot of powder and write it on the jug.

This will help you calculate a cavity for your Auto-Disk that delivers the charge you need to work with.

Thank you Ranch Dog!

I just got back from the range with only a couple of hiccups. Had two rounds not fire, the primer appeared only barely struck, I ran them again and they fired. I probably should have shot a photo of them to show you guys, so I could determine why they didn't fire. I was told by a guy at the range that it might have been because the primers weren't seated fully. Any thoughts?

Also had two get stuck on the ramp and needed a little help seating. I guess that could have been a slightly light load.

All and all I am happy with the experience, nothing blew up and I left the range with about twice the brass than I went with!

[Ranch Dog]

I just got back from the range with only a couple of hiccups. Had two rounds not fire, the primer appeared only barely struck, I ran them again and they fired. I probably should have shot a photo of them to show you guys, so I could determine why they didn't fire. I was told by a guy at the range that it might have been because the primers weren't seated fully. Any thoughts?

Yeah, not fully seated. The firing pin used it's energy to finish the task. Just make sure you really pay attention while seating the primers so that the same pressure is used. You will figure it out.

[Rooster59]

You're not alone cobalt. In addition to coming up short on most or all of the recommended disks with the few powders I use, it takes about 5 throws after changing disks to get the charge weights to "level out" and remain consistent.

One thing I didn't see recommended in the previous replies is hopper volume. I find, even if I don't need it, I try to start with the hopper almost full and don't let it get below half full. It seems to me pressure from the hopper supply maintains its consistency with a hopper more full.

A friend who has reloaded probably millions of rounds from another forum has multiple pro auto disk measures. He has assured me the recommended disk almost never drops the claimed amount of powder. He and I get different weights from the same disk and powder so specific gravity and method probably plays a part in the differences. The measures are very consistent with most powders that it is recommended for, just know the hole size to charge weight chart is a starting point.

Reloading is an exact science only when your methods, your tools, your powder lots, etc. are massaged into your system.

Congratulations on a successful loading session and range trip.

Jeff