how much is to much variance

[rupie]

I'm having issues, I am loading solo 1000 in a dillon 550b, my first issue is I sat down to load some bullets and checked my powder charge and it was at 5.1 grains. What I want is 4.4 grains. I ran a couple of more checks and they were right around the same. This means that last time I loaded I was around .5 grains over on charge. I dont know how many got that (I haven;t fired any of them yet) so I tried to set the powder measure again and I got it to the point that with each pull I might get 4.3 grains and I might get 4.5 grains. No adjustment makes it any better.

I am using an electronic scale that someone on here recommended so this could be part of the issue. But to check it I lifted the same charge up and set it back down several times and the value was always repeated.

I guess my question is this, should I be able to use solo 1000 and set the charge to 4.4 and get 4.4 every time I pull the handle? My powder measure is the older dillon style with the springs. Can this be dirty? I cleaned everything about 1000 rounds or so ago.

[John Dunn]

A tenth of a grain variance high or low is plenty good.

There was a thread about someone placing an aquarium air pump on their powder measure to vibrate the powder into the charge bar more uniformly, might be worth a try.

[Alan550]

My electronic scales get re-calibrated every time I use them, and I let them sit turned on for at least 1/2 hour before I use them. You may get some variance with temperature changes, if you reload room doesn't have a constant temp. Also ANY air currents will make a difference, along with power fluctuations, such as a room heater turning on & off.

Also, I drop 10 charges to be weighed together to get an average. The Dillon powder drop is only accurate to 1/10th grain, as is your scale. Add those together and you can get quite a variance in what each charge weighs. That's why I use the 10-drop average.

YMMV

Alan~^~

[G-ManBart]

Also, I drop 10 charges to be weighed together to get an average. The Dillon powder drop is only accurate to 1/10th grain, as is your scale. Add those together and you can get quite a variance in what each charge weighs. That's why I use the 10-drop average.

+1

I always use a 10-drop average and do that three times (minimum). .1gr +/- is good for an average variation, and it could be half that since the scale is going to round up for anything .05 or higher and down for .04 or lower. R,

[FranDoc]

Solo is a large-particle powder. With the stock powder bar (my Dillon is 'newer', no springs), +/- 0.1 grain was 'normal'.

The most I ever put out of my 4" XD was 4.8 grains. VERY snappy, just a trace of primer flow. I don't know about 5.1 grains ....

Recently put in the UniqueTek micrometer powder bar, trying Solo in .40. The finer adjustments seem to help keep the charge closer to where I want it.

As far as the apparent charge change without changing the powder bar settings, consider this (and the manufacturer may be able to address this in more detail): I suspect that the powder is hygroscopic -- 'gains weight' as it sits in the powder funnel when the weather is humid. I had trouble with this last spring/summer, but not now (furnace is on, drier air). Not sure that can account for a >10% weight gain, through.

[D. Manley]

Also, I drop 10 charges to be weighed together to get an average. The Dillon powder drop is only accurate to 1/10th grain, as is your scale. Add those together and you can get quite a variance in what each charge weighs. That's why I use the 10-drop average.

+1

I always use a 10-drop average and do that three times (minimum). .1gr +/- is good for an average variation, and it could be half that since the scale is going to round up for anything .05 or higher and down for .04 or lower. R,

+1. IMO, by far the way to arrive at the most accurate throws. I make it a practice to validate the electronic scale with a balance beam when doing it too...requires no extra time since you're only weighing averages. If you get in the habit of doing this you might be surprised how long it takes some powders to settle down for real accuracy. Saves a bit of time to go past the desired throw weight (on Dillon machines) and then reduce to target weight...I suppose, because backlash in the powder bar adjustment is minimized this way.

[bkeeler]

I use a 4 drop average and do it about 3-4 times before I start loading. Works out well.

Example:

If I want 4.8gr the 4 drops = 19.2gr and I do it 3-4times.

If I want 4.850gr the 4 drops = 19.4gr.

BK

Edited February 9, 2009 by bkeeler

[WatchmanUSA]

I always use a 10-drop average and do that three times (minimum). .1gr +/- is good for an average variation, and it could be half that since the scale is going to round up for anything .05 or higher and down for .04 or lower. R,

I'm a new reloader and I did some loads this weekend on my Dillon 550. My daughter is a chemistry teacher and she got me access to a scientific grade electronic scale. It measures grains out to the hundredth of a grain (.01) with accuracy of +/- .02 grains. Most scales for reloaders go to a tenth of a grain (.1) but I don't know the guaranteed accuracy (this is another factor to consider). I was noticing that the charges I was getting could vary up to about .06 grains or so. That means, depending on the rounding algorithm of the scale, a regular powder scale could easily swing your displayed charge one to two tenths of a grain with only .06 REAL variance.

[bonnerg]

I think a good practice is to only adjust the powder measure is when the machine handle is DOWN, and the powder measure is EMPTY. Reason: if you adjust to reduce the powder charge and the measure is full, you are actually compressing the powder in the measure. This COULD lead to powder sticking to the inside of the measure.

[Carlos]

Go to the be.com reloading section and search on the term "backlash" - it may help you reduce much of the variance from your Dillon measure.

[warpspeed]

I have no experience with Solo1000 but when I throw powders like Varget, I get + or - 0.1 gr max. I'd lean toward a mechanical issue if you are getting more than that. Do you have more than one powder measure ? If so, try both to see if one is worse than the other.