Charge weights are "wandering"

[gspn]

I was reloading for the 41 mag tonight with 18 grains of Alliant 2400. I'm using a Lee Pro Auto Disc powder measure and the charges kept wandering around. I've used this press for years and I really like it...but this is the first time I've used the auto disc with 2400. I had charges as low as 17.4 grains and as high as 19 grains...all with a 1/2 full hopper and a consistent pull.

That type of range will at best cause accuracy problems and at worst puts me over the max grains level of 18.8 for this particular load.

Any ideas on what's going on?

 

[rfwobbly]

The Lee powder measure, being all plastic, is highly susceptible to static electricity particularly at this time of year. The static can make the powder cling to the inside rather than all fall though. Try wiping all over the inside with some of those anti-static wipes.

 

[gspn]

Thanks RF...I never in a million years would have thought of that one...I'll do that next time I run it.

 

[germ]

If using an electronic scale, make sure it's not doing the wandering.

This past week my 3yr old RCBS 750 has begun wandering. Fortunately the readout has consistently read higher resulting in a lower charge vs higher. I pulled out the lee beam scale and discovered it too is extremely inconsistent and is going in the garbage. The RCBS will likely be joining it, but I want to contact RCBS first.

I have a new Dillon beam scale on the way from Brian Enos.

 

[dickttx]

And make sure that the disk hole is centered over the drop hole in the base when the ram is all the way up. If not, there will be a small ledge where powder can get hung up. Adjust the location of the hole by screwing the flair/powder die in or out.

 

[gspn]

Thanks guys...I'll check all of that today. I calibrate the scale each time I use it but I'll also make a point to use a check weight occasionally throughout the process.

 

[dbarnhart]

I have an RCBS 750 and I have to turn off the ceiling fan when I use it. If I don't then I get the same 'wandering'.

 

[gspn]

Mine is an RCBS too...I've got it insulated from any "wind". It is a bit sensitive in that way.

 

[gamestalker]

I make sure nothing magnetic is near by such as the tumbler, close all the air register's, and no fans running. I only had one really strange incident a while back with my RCBS beam scale that fixed it's self. Everything seemed to be the result of an earth quake prior to, and right after it occured.

 

[1SOW]

I was reloading for the 41 mag tonight with 18 grains of Alliant 2400.

What type of 'particles' does this powder have? I'm not familiar with it.

If it's a flake or large particle powder it can bridge in the powder hole as it's filling. Try tapping the the disc with a dowel as it's filling and again at the drop. Then do drop checks for better consistency.

 

[1SOW]

dickttx, I could be missing something, but the hopper drops way more powder than needed to fill the disc hole. If some is caught on top of the disc, its pulled off when the disc retracts. IF the powder is large flakes/particles it could prevent some of the fill by making the hole-opening smaller.. If it's ball or small rod particles it won't have any effect.

 

[gspn]

What type of 'particles' does this powder have? I'm not familiar with it.

If it's a flake or large particle powder it can bridge in the powder hole as it's filling. Try tapping the the disc with a dowel as it's filling and again at the drop. Then do drop checks for better consistency.

2400 is kind of like really small pieces of stick...not ball and not flake...but not the long sticks either.