Bob Kingsbury
New member
The electronic scales just haven't worked out for me, An acculab just wanders. I have tried it in 4-5 different environments and it
just keeps on. Now I bought a small loading bench job $100 bucks style and actually came to believe it. Then at one point, I
decided that I'd check everything coming out of the measure. Tapping a few kernals out and it read the same. After tapping more out
it still read the same. Now I know from my balance that the 5-6 kernals should have made a change but it didn't. Next charge seemed
fine. This does nothing for confidence, and thats what scales are about. Couple years ago, I bought two scales from e-bay about
$ 30 bucks total together. One was a bit rough, but the other was very tunable. Today while weighing RE-15 I noticed it would
show me one kernal of that stuff. By comparison, my 10-10 and I have two and an older ohaus 505 all of which seem show much
less sensitivity and attrack steel wool which is common to my loading bench. The old scales made Herters and Redding look almost
identicle and are highly tunable
just keeps on. Now I bought a small loading bench job $100 bucks style and actually came to believe it. Then at one point, I
decided that I'd check everything coming out of the measure. Tapping a few kernals out and it read the same. After tapping more out
it still read the same. Now I know from my balance that the 5-6 kernals should have made a change but it didn't. Next charge seemed
fine. This does nothing for confidence, and thats what scales are about. Couple years ago, I bought two scales from e-bay about
$ 30 bucks total together. One was a bit rough, but the other was very tunable. Today while weighing RE-15 I noticed it would
show me one kernal of that stuff. By comparison, my 10-10 and I have two and an older ohaus 505 all of which seem show much
less sensitivity and attrack steel wool which is common to my loading bench. The old scales made Herters and Redding look almost
identicle and are highly tunable
B
bjld
Guest
I'm going to stay clear of arguments about accuracy and sensitivity. The terms I might use are bias and limit of quantitation.
I'll just say that the resolution of the digital display on the GemPro250 is 0.02 grains and it has two calibration points: zero and 308.64 grains.
Still good for $150 and probably worthy of more respect than its raw dollar value. I'm going to sleep on it some more.
Something different to think about: how would you weigh out a drug for an analytical instrument so you could make a solution that's 1.00 mg/mL?
I'd weigh something close to 10.00 mg, maybe 10.34 mg. I wouldn't bother trying to get the weight exactly 10.00 mg - I have better things to do on work time.
Then I'd dissolve the 10.34 mg in 10.00 mL of methanol.
Then I'd take 0.967 mL of this solution and make it up to 10.00 mL with more methanol.
Weighing exact powder charges is a PIA by comparison.
M
mike in co
Guest
C
caroby
Guest
Now, there is really NO better endorsement in the bullet making realm...Any discipline of the shooting realm............. Those that KNOW the OUTSTANDING quality of bullet lead cores that Mr. and Mrs. Hood produce............ None better..! They utilize these great little precision balances (laboratory scales)...! Cool!
I too..... The absolute consistency for volume of bullet cores the Hoods turn out has made me STEP-UP my game on my core squirts.... Increasing my short BR game agg wins has been the results.
If the zero drifts between reloading sessions don't just tare the empty pan, consider recalibrating. Zeroing just resets one calibration point, the calibration weights add more. The GemPro 250 comes with a single 308.64 grain weight. At least my Chargemaster comes with two. I warm it up for at least 24 hours and recalibrate every use.
bjld
Yes, good points... I too perform the same tasks.
cale
B
bjld
Guest
A few posts from people getting years of trouble free use from their GemPro250's gives the cheap scales some real credibility.
Bullet cores and powder charges with typical weights in the 10's of grains probably suit the calibration range of the scale well.
It would be ideal for bullet weights in the 100's of grains and there's probably another model in the GemPro range that suits weights of 0 to 10 grains if you need to go that low.
Consider a calibration curve with two points: the zero (tare) and the 300-odd grain calibration weight.
Calibration curves defined by two points are generally straight lines, so the relationship between the deflection of the mechanism (which you zero) and the displayed weight is linear.
The calibration curve is likely to exhibit more "wobble" around the zero because the calibration weight is likely to produce less variance in its deflection of the mechanism. Wobble is a term I use professionally.
As reloaders we've got high expectations of scales. There's 15000 increments of 0.02 grains in 300 grains.
At work I turn weights of drugs into solutions because the tools for measuring precise volumes of liquids makes handling known amounts of drug so much easier.
A Grade A 10 mL volumetric flask is something like +/- 0.02 mL.
As for measuring a drug in someone's blood or urine? +/- 10% is generally considered acceptable and for the lowest concentrations you can stretch it to 20%.
I've got to sleep on the GemPro250. I'd probably buy it right now but the Australian currency has been doing crazy things for almost a week now. Anyone know why? ;-)
Bullet cores and powder charges with typical weights in the 10's of grains probably suit the calibration range of the scale well.
It would be ideal for bullet weights in the 100's of grains and there's probably another model in the GemPro range that suits weights of 0 to 10 grains if you need to go that low.
Consider a calibration curve with two points: the zero (tare) and the 300-odd grain calibration weight.
Calibration curves defined by two points are generally straight lines, so the relationship between the deflection of the mechanism (which you zero) and the displayed weight is linear.
The calibration curve is likely to exhibit more "wobble" around the zero because the calibration weight is likely to produce less variance in its deflection of the mechanism. Wobble is a term I use professionally.
As reloaders we've got high expectations of scales. There's 15000 increments of 0.02 grains in 300 grains.
At work I turn weights of drugs into solutions because the tools for measuring precise volumes of liquids makes handling known amounts of drug so much easier.
A Grade A 10 mL volumetric flask is something like +/- 0.02 mL.
As for measuring a drug in someone's blood or urine? +/- 10% is generally considered acceptable and for the lowest concentrations you can stretch it to 20%.
I've got to sleep on the GemPro250. I'd probably buy it right now but the Australian currency has been doing crazy things for almost a week now. Anyone know why? ;-)
John Kielly
Shari's fan club
I bought mine in Australia. The price is substantially higher, but it is supplied with a 240V power supply (sent seperately - you also get a 110V one in the pack). This is where I got mine: http://www.medshop.com.au/my-weigh-gempro-250-scale-50g-x-0.001g.html
I haven't had mine very long, but so far I'm happy with its performance. I only use scales to measure up charges when loading a predetermined load. For every load I make a check weight which I use at the start & during loading to verify that its tiny brain isn't scrambled. So far it's been spot on. I use the milligram scale because it can & a milligram is 75% or thereabouts of .02 grain. Who knows, it may even be the actual accuracy of the device. Sensitivity is a little less than it was on a cheap battery unit that I've used successfully for a number of years. The cheap one would usually move a single milligram unit to a single kernel of powder as fine as N550, more of course for heavier kernels & depending on where between the two divisions the "real" mass resided.
The GemPro is fine with coarser powder like AR 2206 onward (sorry audience, Hodgdon never bought that one; there's no US name for it). In any case, I excite the pan each time I add to the pan to make the bugger reassess the charge, like I've always done with electronic scales. I kind of think/hope that I'm getting better accuracy out of it that way. I feed the powder to the pan when it's settled on tare after I dump a charge in the case. Like all the others I've used, it seems to like that. I'm using an old RCBS beam pan on the scale because the dinky one they supply temds to cop a bit of static particularly these dry winter nights. It's a shame that the RCBS pan is so heavy as I would prefer to be operating lower in the scale's weighing range.
I checked liniarity when I got it by the cheapskate's two equal(ish) weights method. Over 100 iterations, each weighed +_ 1 milligram, with about a 60% majority on the same value. Interestingly, when combined, the error was always at least 1 milligram, but never more than 2, so maybe their claim is not unreasonable. I was using 10 gram weights, which only took me half way across the scales capacity anyway.
It chews up AAA batteries when used in standard (as received) mode, but it's fine with the mains powered unit. I'm more comfortable since I picked up a used UPS on Ebay last week & float the power across its battery.
John
I haven't had mine very long, but so far I'm happy with its performance. I only use scales to measure up charges when loading a predetermined load. For every load I make a check weight which I use at the start & during loading to verify that its tiny brain isn't scrambled. So far it's been spot on. I use the milligram scale because it can & a milligram is 75% or thereabouts of .02 grain. Who knows, it may even be the actual accuracy of the device. Sensitivity is a little less than it was on a cheap battery unit that I've used successfully for a number of years. The cheap one would usually move a single milligram unit to a single kernel of powder as fine as N550, more of course for heavier kernels & depending on where between the two divisions the "real" mass resided.
The GemPro is fine with coarser powder like AR 2206 onward (sorry audience, Hodgdon never bought that one; there's no US name for it). In any case, I excite the pan each time I add to the pan to make the bugger reassess the charge, like I've always done with electronic scales. I kind of think/hope that I'm getting better accuracy out of it that way. I feed the powder to the pan when it's settled on tare after I dump a charge in the case. Like all the others I've used, it seems to like that. I'm using an old RCBS beam pan on the scale because the dinky one they supply temds to cop a bit of static particularly these dry winter nights. It's a shame that the RCBS pan is so heavy as I would prefer to be operating lower in the scale's weighing range.
I checked liniarity when I got it by the cheapskate's two equal(ish) weights method. Over 100 iterations, each weighed +_ 1 milligram, with about a 60% majority on the same value. Interestingly, when combined, the error was always at least 1 milligram, but never more than 2, so maybe their claim is not unreasonable. I was using 10 gram weights, which only took me half way across the scales capacity anyway.
It chews up AAA batteries when used in standard (as received) mode, but it's fine with the mains powered unit. I'm more comfortable since I picked up a used UPS on Ebay last week & float the power across its battery.
John
O
ozfclass
Guest
I've had a GemPro 250 for a little over 2 years. Its my third (first 2 replaced under warranty) and all 3 had different serious problems. I actually gave up on the third one, and put it away, then had another try months later and it worked! And has been going faultlessly ever since - doesn't even drift noticeably. I use it in conjunction with a cheap (Lee) powder thrower into a Redding No 2 scale, trickled up to weight. I then move the pan onto the GemPro for a check reading. If it reads more than 0.02gn either side of the mean, then I add or subtract kernels. However this happens about 1 in 10 times at most, which means that the old-fashioned Redding scales are very good, better than 0.1gn accuracy in fact. I think analog balances are better to trickle into - easier to get a feel for. But I'll continue to use the GemPro mainly as a check against gross error. So my advice to anyone who has a problem such as drift with a GemPro is to return it under warranty and it'll get replaced - and if necessary keep doing that until you get a good one!
Alan
Alan
Bill Scheider
Bill Scheider
Reloading Scale Comparison
We have recently run fairly exhaustive comparisons between our seemingly myriad of scales.
We compared thrown charges from our Harrell's Measure and dispensed charges from the Chargemaster.
Scales Compared:
1- RCBS Chargemaster
2- RCBS 10-10 Scale
3- Dillon electronic scale
4- Denver MX-123 Electronic Scale
5- Mettler AE 200 Analytical Electronic Balance Scale with enclosure.
All were calibrated with RCBS and furnished certified check weights.
The most accurate, consistent and easiest to use scale is by far the Dillon
.x Gr.
The Chargemaster, though calibrated, consistently read .2 grains off target.
What we thought to be 34.6Gr. H4198 scaled at 34.4 gr. on all other scales.
RCBS 10-10 is inconvenient to say the least.
Denver MX 123 reads to .0xx Grains, but drifts.
The Mettler AE 200 is dead-on but not as convenient to use. The .000x grams converted to Grains is nice for all of our Bullet-Making chores.
FWIW, the Harrell's Powder measure is much more consistent and convenient, in our testing, and will be used in place of the RCBS Chargemaster which we previously thought was the last word in reloading.
Our opinions and findings only_ Sometimes simpler is more consistent it seems.
Buy the Dillon Electronic scale.
Bill
We have recently run fairly exhaustive comparisons between our seemingly myriad of scales.We compared thrown charges from our Harrell's Measure and dispensed charges from the Chargemaster.
Scales Compared:
1- RCBS Chargemaster
2- RCBS 10-10 Scale
3- Dillon electronic scale
4- Denver MX-123 Electronic Scale
5- Mettler AE 200 Analytical Electronic Balance Scale with enclosure.
All were calibrated with RCBS and furnished certified check weights.
The most accurate, consistent and easiest to use scale is by far the Dillon
.x Gr.
The Chargemaster, though calibrated, consistently read .2 grains off target.
What we thought to be 34.6Gr. H4198 scaled at 34.4 gr. on all other scales.
RCBS 10-10 is inconvenient to say the least.
Denver MX 123 reads to .0xx Grains, but drifts.
The Mettler AE 200 is dead-on but not as convenient to use. The .000x grams converted to Grains is nice for all of our Bullet-Making chores.
FWIW, the Harrell's Powder measure is much more consistent and convenient, in our testing, and will be used in place of the RCBS Chargemaster which we previously thought was the last word in reloading.
Our opinions and findings only_ Sometimes simpler is more consistent it seems.
Buy the Dillon Electronic scale.
Bill
M
mike in co
Guest
bill....
what powder did you do this test with ?
my tests with n133 oem 8208 and imr8208 says the harrells is not as accurate as most think it is.
the mx123 shows the harrells to be plus or minus .2/.3 with n133, .09 with imr8208 and .05 with oem 8208...just plain accurate.
my older dillon is not that good....i have quit using it....how new is your dillon ??
so just goes to show ya......dang
mike in co
what powder did you do this test with ?
my tests with n133 oem 8208 and imr8208 says the harrells is not as accurate as most think it is.
the mx123 shows the harrells to be plus or minus .2/.3 with n133, .09 with imr8208 and .05 with oem 8208...just plain accurate.
my older dillon is not that good....i have quit using it....how new is your dillon ??
so just goes to show ya......dang
mike in co
B
bjld
Guest
I've bought a MyWeigh iBalance 211. It's from the same vendor as the GemPro 250 but it costs three times as much. Hopefully it's buy once, cry once.
I ended up deciding that a precision balance without a windshield couldn't be considered a precision instrument. Just a hang over from using them at work, I guess.
I bought a set of check weights as well to gauge its performance - I'll let you know how it goes if it makes it here from the US intact.
Regards
Ben
I ended up deciding that a precision balance without a windshield couldn't be considered a precision instrument. Just a hang over from using them at work, I guess.
I bought a set of check weights as well to gauge its performance - I'll let you know how it goes if it makes it here from the US intact.
Regards
Ben
Attachments
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max.burgess
Guest
The add said the Gem Pro had a maximum weight of 50 g I guess that is grams. Does it have a switch for grains? Thanks Max
B
bjld
Guest
The GemPro 250 reads in grains, the iBalance 211 does not.
Good conversions would be 0.001 grams is 0.01543236 grains, 1 grain is 0.0647989 grams.
0.001 grams gives the iBalance a resolution of about 0.015 grains.
200% more money, 25% better resolution.
The relationship between cost and resolution is not linear.
Good conversions would be 0.001 grams is 0.01543236 grains, 1 grain is 0.0647989 grams.
0.001 grams gives the iBalance a resolution of about 0.015 grains.
200% more money, 25% better resolution.
The relationship between cost and resolution is not linear.
M
max.burgess
Guest
In the add on that web site it said the maximum weight was 50 g . Is that grains or grams ? Thanks Max
Boyd Allen
Active member
Grams.....the abbreviation for grains is gr.