Stupid gempro 250

[Ffjmoore]

I bought a gempro 250 from a member because my beam scale is slow. I got it to work ok. I had to calibrate it pretty frequently but as long as I kept an eye on it my weights were repeatable. But today I was using it to load some 9mm and it was not working right. I could not get it to read consistent. I would calibrate and change it to grains with the 20 gram check weight it would show 308.66gr. Close enough but when I would put the pan on, tare the scale and add the weight it would be way off. It was telling me my 115gr bullets were 110. I tried my 140gr bullets and it said they were 135. I calibrated with the 20gram and 50 gram weights but the lower end was off. I had just loaded up 100 rounds of 6.5cm using the scale. 41.2 grains of h4350. So I grabbed 2 of those rounds and pulled the bullet and weighed the powder. It wasn't 41.2gr, it was 41.8. I verified it on 2 separate beam scales. Needless to say I'm a little frustrated that I spent that much money on a scale that doesn't work. I guess I'll just be going slow and using both of my beam scales to verify my loads.

 

[Dstoenner]

Have you used a dryer sheet on it to get rid of any static build up? Have you recalibrated it? I have also heard it is sensitive to being close to florescent lights. Did you have to turn them on for this latest loads?
david

 

[Ffjmoore]

I have re calibrated multiple times. I'll try the dryer sheets and florescent lights. I think the lights I have near by were led but I'll double check.

 

[ShtrRdy]

Along with what has been mentioned, is your cell phone near by?

 

[bjay]

This scale need to be warmed up good

 

[Dstoenner]

This scale need to be warmed up good

I agree with that. In fact I leave mine on all the time and won’t use it till it has been on for 24 hours

David

 

[Ffjmoore]

Yah, I was leaving it on. The part that bothers me was that I was able to get consistent results with standard deviations sub 10, but that the readings are inaccurate.

 

[Pvt.Donut]

1. Scales need to warm up. Plug it in, turn it on and leave it overnight.

2. Keep the scale away from florescent lights.

3. Keep your cell phone away from the scale, 10 feet at least.

4. Remove any static cling.

 

[Ffjmoore]

I brought it in the house and it seemed to work much better other than some drift because it wasn't warmed up. I put it back on my bench and unplugged the florescent light that was over head. Blows my mind that it could be the main problem. I'm leaving it on over night and ill test it again tomorrow when I do a small batch of 6.5cm

 

[Sheldon N]

I'm leaving it on over night and ill test it again tomorrow when I do a small batch of 6.5cm

Another tip, keep an eye on the negative number every time you lift the pan. That will give you advance warning that the scale is drifting and allow you to re-zero.

 

[John Glidewell]

It is a strain gauge scale too, so it reacts slow if you are trickling in pan. Trickle a few kernels and lift the pan, check the -# and then set pan back on scale, you will see more accurate weights. A bit of a pain but I used the gempro 250 for a year. If you are outside / in garage, think about trying to move indoors or run a heater and humidifier on other side of garage (if cold). I moved my reloading area indoors so I could control the conditions better. If it is cold and low humidity then static is most likely present. Statically charged powder floats on a scale and will make it walk.

 

[DTF370]

Also be careful of air movement. Example, don’t rely on it while your heater, air conditioner, or fan are running. They’re sensitive to both air movement and temperature swings.

 

[Ffjmoore]

I loaded some rounds last night. Phone 10 feet away, florescent lights off and no wind and has been on for over 24hrs. I looked for dryer sheets but my wife is a bit of a hippie so she doesn't use them and uses "dryer balls"instead. I'll steal some from work next week.
Anyway, it worked fairly well. I kept and eye on the negative and confirmed the check weight was correct. I did tare once or twice but it's working acceptable now.
I think the major issue was the florescent light overhead.

Thanks guys. I was ready to throw the thing in the trash.

 

[Will65284]

In a pinch (no dryer sheets). I've sprayed R.E.M. Oil on a micro fiber cloth and wiped each piece lightly. It helps big time with drifting. Also. This sounds crazy. But ...... make sure your not breathing directly over top of it. Just you exhaling on it causes it to go nuts. I had the same issue with my FX120i Auto throw/trickler setup. Once I backed up a bit. Problem was solved.

 

[TCKev]

I bought a gempro 250 from a member because my beam scale is slow. I got it to work ok. I had to calibrate it pretty frequently but as long as I kept an eye on it my weights were repeatable. But today I was using it to load some 9mm and it was not working right. I could not get it to read consistent. I would calibrate and change it to grains with the 20 gram check weight it would show 308.66gr. Close enough but when I would put the pan on, tare the scale and add the weight it would be way off. It was telling me my 115gr bullets were 110. I tried my 140gr bullets and it said they were 135. I calibrated with the 20gram and 50 gram weights but the lower end was off. I had just loaded up 100 rounds of 6.5cm using the scale. 41.2 grains of h4350. So I grabbed 2 of those rounds and pulled the bullet and weighed the powder. It wasn't 41.2gr, it was 41.8. I verified it on 2 separate beam scales. Needless to say I'm a little frustrated that I spent that much money on a scale that doesn't work. I guess I'll just be going slow and using both of my beam scales to verify my loads.

I did several things to get my RCBS Chargemaster to stop drift that would help anybody with electronic scales. You can add a Radio Shack Ferrite Core to help EMI or electro magnetic interference, Next I have it plugged into a battery back-up that cleans up the electricity and the other thing I did was replace the florescent bulbs with line voltage LED tubes, takes out the ballast interference and you have better lighting.

RadioShack Snap-On RF Choke with Ferrite Core

This pack of two snap choke cores are an effective, easy-to-use EMI/RFI fighter. Just snap the 13x25.2x3.5(mm) ferrite core over coax cable, AC or audio cord. It prevents electro-magnetic interference (EMI) and cuts down on radio-frequency interference (RFI). Parts Warranty: 90 Days

www.radioshack.com