I use subject scale to reload with.  Scale stays plugged in all the time with nothing else plugged into the outlet, so warm-up is not an issue.  No fluorescent lights in the room.   Scale sits on my bench and is used as I throw charges.  Bench is rock solid on a carpeted, concrete floor in my finished basement spare room.  No vents in the room except one in the bathroom 10' away.  

I'm not a precision loader, but like the charges to weigh properly.  Did some .223 today and noticed the drift was +/- .02 to .06.  Not sure why this is happening.  Decided to call it quits.  

Just for the heck of it, I recalibrated the scale to zero as shown below.  



Once zeroed, I pulled the pan off the scale, closed the top, and walked away.  Reading as shown here:



Came back 10 minutes later and here's what I get on the reading:



Heat is not running, no cell phone nearby, not working on/near bench....nothing!  Why does the reading move .06+?  
Just looked at it as I'm typing this up and it now reads -124.08, a drop of .08

 For you long time reloaders, is this much of a drift gonna really matter in the big picture?  I'm using the ammo for plinking and zeroing.  If I was precision loading for matches et al, I'd be using my beam scale at this point.   No funds available to even consider a $500+ precision lab scale.  
Any input or advice on how to address this is greatly appreciated.

Static.

Wipe your hands, powder dish, and top of the press with a dryer fabric softener.

Thanks.  I'll give that a try next time.  

Any static charge can drift it.   Items on the bench, the bench itself.   You...  just about anything.  You say no florescent bulbs..  you have no cfl's or dimmers on the same circuits?  Led lights use a sort of a transformer with a magnetic field.


All that said... if you are that worried id suggest moving to a lab grade balance beam or a more expensive digital.  I know you said $ is a factor.  When someone asks me how fast I can make their car, the only question is:  How fast can you AFFORD to go?  

You basically are at the limit of you pocketbook.

You say it's plugged in all the time. But is the scale turned ON all the time? The strain gauge won't warm up and stabilize for (eg) 30 minutes after it is turned on.

As exigent said, you are at the limit most people have found. The GemPro 250 is reputed among the best for under $600. At that price point you can get a magnetic force restoration balance, and the problems you see will disappear . . . along with a wad of money lol.

It doesn't trickle well, it eats batteries, and it will drift even if you think your room is free of all noise. Just the way it is.

BTW, If you have to frequently re-zero, re-calibrate it (and/or test some check weights) as well. This can help avoid cumulative error.

You've got a huge negative reading associated with the tare weight of your pan and it drifts over time.  My question is "So what?".

I admit I'm not a scale expert, but I do have the same scale as you do and this kind of drift doesn't bother me at all.  But that's not to say the scale won't drift.

I get the feeling (experts can chime in here to correct me) that when I replace my empty pan back on the scale that device seems to search for zero.  In other words, sometimes it returns immediately to zero but some times it returns to plus or minus a few hundredths of a grain and over the span of eight or ten seconds it eventually returns to zero.  Is it really self zeroing or not?  I don't know but it seems to me as though it's trying to self correct any drift from the zero point which may have occurred while the pan is off the scale.  Once it finds zero, my scale seems to hold that for a long long time.......... long enough that I get tired of checking............ several hours at least.  Is the scale actually steady or does it perform some sort of self correcting routine to maintain that zero point?  I'd like to know, but more out of curiosity than anything else.  Experts feel free to chime in.

I've also noticed that if I trickle and overshoot the target and then try to remove a few kernels and trickle again and fiddle around long enough, when I finally dump the pan and return it to the scale, the zero sometimes drifts and does not return to zero. This kind of drift only seems to happen when I fiddle around for much longer than normal and especially when I remove some powder and try to trickle up to the target weight.

I just accept this as a byproduct of spending less on my scale than I did on my gun.  If the scale doesn't return to zero when I replace the empty pan, I zero it, dump a kernel or two from the case, and reweigh the charge, trying this time to trickle up to the target weight more quickly.  This seems to work pretty well.

By the way, I use one of those plastic pans with a built in funnel which fits over my .223 and 6MM case necks.  It's great for dumping powder into the case but it doesn't fit the indent in the scale pan very well, so I carefully cut a disc from a piece of beer carton and glued it onto the bottom of the pan/funnel.  It is sized to fit the indentation in the scale so that it returns to the exact same place every time.

My will drift just like yours if I leave its left on and doesn't get used.  If I zero it and then start using, the drift isn't nearly as bad.  I re-zero the scale every 10 to 15 rounds anyway.  

Once you actually start using it for reloading, does it drift on you?  If it doesn't I wouldn't worry about it.

Side note, IMHO I think its a bad idea to leave on in all the time.  Maybe if you got it plugged into a line conditioner it will be okay.  I just don't think the minor variations in the power are good for such a sensitive (and jittery) scale.  When I'm planning to reload, I power the scale on ahead of time to let it warm up.

0.02 - 0.06 grains of drift is so neglible it's not worth worrying about- it probably equals 1 kernel or flake of powder- What you're seeing is within calibration tolerances.

If the scale was drifting 0.2 - 0.6 then you'd have a concern.

The Gempro is sensitive enough to register air movement.  That's why it has that cover built in.  I'm drawing up plans for a clear plastic box to keep my 250 in, so that I don't have that same issue.  For quick measurements, the issue you're seeing is inconsequential; I just recently used my 250 to speed up adjusting my powder measure for several test loads, and once I was "really close" I used my balance scale to verify the actual weight.  Not that I'm "happy" about that, but I was very much aware that air movement in the room was the culprit.

Also, as long as the "drift" isn't more than a few 1/100ths of a grain, it's trivial - granules of most powder weigh several 1/100th of a grain, so we're talking about "trickler error" with anything less than 0.004 variance - essentially in both directions.

Yes, listen to what FB41's saying (GH too, he posted while I was correcting my spelling stink).  The Gem Pro reads too many decimal places and screws with your head.  Rounding.....24.2 gr....Both!  They both read the same tenth of a grain......geeze most others wouldn't even read a difference.  Relax and smile, you just have to reteach yourself how to read it....round then document.

This issue is called "precision versus resolution."  The scale is splitting very fine hairs, and shows you far more data than you need.  That last digit is ONLY useful if you see a trend, with the number getting progressively higher or lower over many, many different measurements.

Thank you all!  Good info to chew on.  Unless precision shooting, the consensus seems to be on not worry about a few hundredths.

Even when it drifts a lot, all you have to do is hit the zero button before dumping into the pan.



0.02 gr is one, single kernel of Varget powder.  Is that relevant to anyone?  The answer is, no.

Flake-type pistol powders and ball powders weigh less per kernel but you get the idea.

Your 0.02-0.06 grain variance wouldn't make any difference with precision loads, either.  The ultimate best benchrest powder measures are good to ±0.05 grains (such as the Harrells Classic Culver measures).  5 hundredths of a grain is a granule of powder...  Nothing to worry about.

I've used mine for awhile...............

A couple of things:
-The Gempro doesn't work well trickling.  Their website says so and I found that to be true.......... It drifts.  

-I use a surge protector which settled it down for me................

-Once set-up the gempro works great for me, no drift and no problems.

-Continuiously resetting the scale to zero makes things worse, not better, it doesn't allow it "to settle down."  I tried that once before I figured it out and it didn't work.  In other words, I found that doesn't really zero it, it will drift anyways.  

My guess:
If you are trickling into the pan on the scale, that is the issue.  The scale will jump around (drift) as it senses the added powder.  When I tried it and figured it out, I realized the problem.  For powder charges I use it to verify the weight, not for trickling.        

Methods of Work for Electronic Scales -

Resetting to zero removes the accumulated drift up to the point you punch the button.  It does not stop the drift, it removes the effect.  Hit zero, let it get to zero, then dump into the pan.


Trickling - tap the pan with your finger to get it out of the locked display mode and into measurement mode.  Then start to trickle.  It will read the additional powder, even small increases.

If you just trickle into the pan while the display is locked, it will not read the additional powder and will just remain locked.  If you trickle in at a high enough rate, it might jump into measurement mode.  The rate of increase (grains per second) has to exceed some threshold value.


I hope this helps.

Trollslayer:

The problem is in what you just said.
I found the scale would be drifting.  Hit the zero, it would pause and then continue drifting, not allowing a good measurement.  

As You said............hitting the "zero" does not stop the drift.  If the scale is constantly drifting, I could hit the "zero" all I wanted and it would go back to drifting..........  



Op:
Maybe this will help you:

http://myweigh.com/support/

(BTW- they refer to "trickling" as "dribbling")  

Hmm,... I don't have a Gempro but have had lower priced electronic balances, so I am familiar with drift.

I would have to say this.  If your scale drifts so much and so fast that you cannot hit the zero button and dump into the pan for an accurate reading, something is wrong with your electronic scale.   How much drift are you getting (gr/sec)?

If the Gempros are all like that, perhaps the Gempro is not appropriate for reloading.

What level of accuracy are you after?  All measurements have error associated with them.  How much inaccuracy in powder charge weight are you willing to accept?

Changes of -0.0001gr/sec (-0.06/10 minutes) are irrelevant if you use the techniques I described above.


For that matter, variations in charge weight of 0.06 gr are irrelevant, too.