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October 3rd, 2015

Ten Commandments for Use of Electronic Scales

Denver Instrument, maker of the MXX and Timberline Series of precision balances, has created a helpful guide explaining how to get the best performance from a digital scale. Denver Instrument knows that, to achieve and maintain a very high level of accuracy with digital scales, they must be calibrated regularly, leveled properly, and kept away from sources of interference. Unfortunately, some reloaders treat their electronic scales as if the machines were toasters — something to place on a tabletop, plug into an outlet, then “set and forget.” There’s a better way to set up your scale and keep it functioning optimally. Here are ten guidelines provided by Denver Instrument. Follow these “Ten Commandments” and you’ll benefit:

Denver Instrument MXX-123

Denver Instrument MXX-123ONE: Thou shalt choose the best resting spot. The performance of your balance depends greatly on the surrounding environment. Choose a location away from the main traffic flow of the room, especially doors. Also be aware of heating and cooling vents as these produce air movement. You can adjust the environmental settings on your balance to provide the best performance in the chosen location. Balances must be placed away from magnets as they affect the weigh cell performance.

TWO: Thou shalt avoid vibrations. Vibrations can come from large machinery in production environments and from fume hoods in laboratories. An alternative to fume hoods are Power Safety Workstations which are designed specifically for use with a balance.

THREE: Thou shalt watch temperature changes. On an analytical balance a one degree temperature change can cause a 1 digit (0.0001g) drift. Although Denver balances have temperature correction built-in, it is still important to calibrate your balance when the temperature changes significantly. Choosing to place your balance in a temperature controlled room, away from sunlight, and calibrating often helps minimize the effects of temperature.

FOUR: Thou shalt calibrate often. Upon installation and each time the balance is moved you should calibrate your balance. For example moving an analytical balance to a location that is only 13 feet higher changes the weight reading from 200.0000 g to 199.9997 g; which means the result is 0.0003 g lighter than the actual mass.

FIVE: Remember to check the level. The instrument should be leveled upon installation with all feet (two front feet for round pan units, four feet for square pan units) touching the countertop. If the level changes, the balance should be re-leveled and recalibrated. As an example, a 200g sample would weigh 0.0025 g less when tilted at an angle of 0.3°.

SIX: Honor thy weights. Keep in mind that weights are only as reliable as their quality and certification. Remember, a 1 g does not weigh precisely 1.00000 grams. Weights should be recertified annually. Denver Instrument offers recertification services on all weights 1 mg to 5 kg. Check to make sure you have selected the proper weight class for your balance. The weight tolerance should be better than balance readability. Always use tweezers or gloves when handling weights as smudges and indentations change the value of the weight. Keep weights in cases so they don’t get scratched or dusty.

Denver Instrument TimberlineSEVEN: Thou shalt always use a small container and weigh in the center of the pan. Especially when using an analytical balance, the effects of air buoyancy increase as the sample container size increases. Using a small sample container will minimize the effects. Items placed on the pan provide a downward force. Placing them directly in the center of the pan keeps corner loading errors at a minimum.

EIGHT: Thou shalt not unplug. To perform within published speci-fications, balances must have power applied for 30 minutes to 48 hours depending on the resolution of the balance. Denver balances have a standby mode which turn the display to standby but keep power cycling through the electronics.

NINE: Thou shalt not ignore static. Static is one of the most common weighing “noises”. It can cause reading to appear too high, too low or just be unstable. Denver balances include grounding methods to reduce the effects of static. However sometimes extra supplies are needed. Consider anti-static weigh dishes, anti-static brushes or low tech ways to increase the humidity of the chamber like placing damp cotton balls or glass wool in a small vial in the corner of the analytical draft shield.

TEN: Thou shalt clean often. Dirty weigh pans and powder in weighing chamber can contribute to static issues and lead to a wide variety of problems. Denver weigh pans are made from stainless steel and can be cleaned using a variety of household and laboratory chemicals. A small paint brush can be used to get power away from the edges of the draft shield for easy clean up.

Permalink Reloading, Tech Tip 5 Comments »
September 9th, 2012

Digital Scale Comparison: GemPro 500, AY123, Sartorius GD503

This article first appeared in 2011.
JayChris,’s IT “guru”, has tested three different digital scales. The first is the relatively inexpensive ($150.00) GemPro 500, the second was the $333.00 Sartorius AY123, which is very similar to the Denver Instrument MXX123 and Acculab-123. Lastly, JayChris tested his $1225.00 Sartorius GD503 lab scale. The 3-way comparison test produced interesting findings. We learned that the AY123 had some serious shortcomings when used to weigh powder. The GemPro 500 performed well for the price, but was quite a bit slower than the big GD503. In speed of response, accuracy of measurement, resistance to drift, and overall reliability, the GD503 was the clear winner in our comparison. Sometimes you do get what you pay for. CLICK HERE for GD503 Review with Videos.

digital scales GD503, AY124, GemPro 500 250


Three-Way Comparison Test: GemPro 500, Sartorius AY123, Sartorius GD503
Testing Report by JayChris
Precision Weighing Balances,, an authorized Sartorius Distributor, shipped me an AY123 (same as Denver MXX123, Acculab 123, etc.) along with a high-end GD503 force restoration scale. I had purchased the GD503, while the AY123 was a loaner for this comparison test. I included in this test a GemPro 500 scale that I already had. My key objective in this comparison test was to test each scale for measurement drift over time. We wanted to see if the displayed weight of a given object (here a certified test weight), would change over time, or with repeated measurements.

The first test was a “quick” test, where I measured the same weight ten (10) times, in the same order, about every 30 seconds or so. I did this at about the same speed as weighing out powder, maybe a bit slower. This took about 5 or 6 minutes. The second test was more-or-less an overnight test, where I measured the same weight in lengthening intervals, starting every 10 minutes, then every 30, then every 60, and so on. You can see the time series on the included graphs.

digital scales GD503, AY124, GemPro 500 250

– I used the same 100 GRAM Sartorius certified check weight for every test (see photo). Note: 100 GRAMS = 1543.233 GRAINS
– I calibrated each scale within 30 seconds of each other before starting the test.
– I tare’d each scale within a few seconds of each other
– All three scales are connected to the same line conditioning PDU and are located in the same environment (right next to each other)

Measurement Resolution and Display Increments
– The Sartorius AY123 measures to the nearest hundredth of a grain (.00). Increments are in 0.02 grain divisions, i.e. the nearest two hundredth of a grain.
– The Sartorius GD503 measures to the nearest thousandth of a grain (.000). Increments are in 0.005 grain divisions, i.e. the nearest five thousandth of a grain.
– The GemPro 500 measures to the nearest half-tenth of a grain (.05).

NOTE: When weighing powder, I weigh to the nearest .05 grain so any of these provide adequate (or more-than) resolution.


digital scales GD503, AY124, GemPro 500 250

* X-axis is weighing series iteration


digital scales GD503, AY124, GemPro 500 250

* X-axis is a time series in minutes-from-0.

THIRD SERIES AY123 “Stable” vs. “Unstable”:

digital scales GD503, AY124, GemPro 500 250

* X-axis is a weighing series iteration

This is a test of the AY123 in “Stable” vs. “Unstable” environment mode. The GD503 was used for comparison. I ran this test to compare the AY123 in “Stable” conditions mode (default) vs. “Unstable” conditions mode, based on anecdotal reports that the “Unstable” mode produces more consistent results. I did not find that to be so. In addition, I found that the weighing time for the “Unstable” mode was extremely slow — taking nearly 5 – 7 seconds per instance to complete a measurement. It then takes a few seconds to return to zero. In the AY123’s default “Stable” mode, it takes a second or so. Based on my testing then, there is no advantage to running the AY123 (or similar clones) in the “unstable mood”. It will simply slow you down.

Observations and Conclusions
Overall, the GD503 was the most consistent, never varying more than .005 (five-thousandths) of a grain, which is about ten times less drift than the next closest scale. The GemPro was “close” behind, never varying more than .05 of a grain. The AY123 was consistently variable and lost significant resolution over time. It was difficult to plot the AY123 results because it rarely settled at a weight for longer than a few seconds — it would routinely come up with a different weight every few seconds, varying by as much as .04 of a grain. I selected the first reading it “settled” on as the “official” reading.

The one thing this test does NOT demonstrate is trickling — our previous Review of the GD503 has a video that shows that nicely. The GD503 gives you near instantaneous read-outs when trickling. By contrast, both the AY123 and GemPro 500 require a “trickle-and-wait-for-update” plan. The GD503 is really dramatically better in its ability to return a “final” weight very quickly. This allows efficient trickling. CLICK HERE for GD503 Review with Videos.

[UPDATE: One of our readers observed that there is a setting which can make the AY123 more responsive (and accurate) when trickling charges: “Note that the video shows the 123 jumping as powder is added. The reason is the scale is in the default setting, which is for single weightings. When changed to ‘Filling’ mode, the scale reacts very quickly, and in my case accurately. Trickling is easy in the ‘Filling’ mode. My experience is that the AY123 is an excellent scale, but is sensitive to environmental factors. The GD503 is way better and is also way more expensive.” — Matt P.]

GemPro 500 Performed Well — Drift Was Usually Minimal and Charges Settle Fairly Quickly
I’ve used the GemPro 500 for quite a while now and have found it to be fairly reliable. However, over one previous loading session I have seen it drift as much as .150 of a grain. I had to go back and re-weigh charges because of this. Therefore, I tend to tare it every five (5) weighings or so which is probably overkill based on one case. I’ve not had that problem since so I am guessing something happened environmentally (maybe I bumped it or something). Overall, the GemPro is not overly sensitive to environment and settles fairly quickly and reliably.

Charges Weighed by SD503 Have More Consistent Velocities, with lower SDs
I’ve loaded a few hundred rounds with the GD503 now. I have not found it to drift more than .010 of a grain in that time. So, now, I only tend to tare it once at the beginning of a load session. I have gotten extremely consistent velocities from charges loaded with this scale, with single-digit standard deviations. By contrast, previously, my best efforts usually resulted in standard deviations (SDs) in the low teens.

Based on my experience testing the AY123, I would not choose this scale to load powder with. The readings are just too variable. The slightest environment factors (breathing, hand movement, etc.) cause large changes in results. I tried to load some rounds using this scale (backed by my GD503 to verify) and I couldn’t do better than a few tenths of a grain, and that was with considerable effort. The Sartorius AY123 is really the wrong tool for the job when it comes to measuring powder.

Thanks to Precision Weighing Balances for providing the AY123 for comparison. The other two scales, the GemPro 500 and GD503, I purchased on my own nickel. [Editor’s Note: When purchased in 2011, Jay’s GD503 cost approximately $900.00. The current 2012 price at is $1225.00.] All three of these digital scales can be purchased through the Precision Weighing Balances webstore:

GemPro 250 | GemPro 500 |AY-123 |GD503

Permalink Gear Review, New Product, Reloading 8 Comments »
September 9th, 2011

Sartorius GD503 Analytical Scale Offers Amazing Precision

Sartorius GD503 force restoration magnetic scaleSuccessful long-range shooting demands very uniform ammo. Weighing charges carefully can make shot velocities more uniform within a shot string. Uniformity of velocities is good, because lower ES translates to less vertical dispersion of the shots at long range. Many competitive shooters today try to load charges that are consistent within one-tenth of a grain. Some exacting reloaders, in the relentless pursuit of perfection, go even further — they try to maintain charge weight uniformity down to the equivalent of just one or two kernels of powder.

To weigh charges with this kind of precision, you need a very high-quality scale. Even the $400.00-grade balances (such as the Acculab VIC-123), struggle to maintain single-kernel precision with their conventional strain-gauge load cell technology. But there is a new class of electronic lab scales which employ magnetic force restoration technology. These force restoration balances can reliably (and repeatably) weigh a single grain of powder. In normal use, lab-grade force restoration scales also deliver a stable reading more quickly than strain-gauge type scales. This is a boon for reloaders who like to trickle the final few kernels of a load. But the enhanced speed and precision of force restoration (magnetic) scales come with a stiff price — these technological marvels cost $900.00 and up. That could buy a custom action, or three new barrels.

Trickling Kernel by Kernel with GD503 and Omega Trickler
Do the advanced force restoration scales perform as advertised? Can they reliably recognize a single kernel of powder quickly enough to make trickling practical? Well, thanks to Forum member A.J. (aka AJ), we have a video that answers those questions. Using a Sartorius GD503 Class II force restoration balance with an Omega two-speed powder trickler, A.J. demonstrates how he can weigh charges that are consistent within a single kernel’s weight, i.e. 20-25 thousandths of a grain.

When you watch the video, note how (at 3:45 time mark) the RCBS electronic scale reads 41.7 grains, when in fact the correct charge weight was 41.830 grains, as measured by the GB503. That’s a one-tenth grain (four kernel) error right there. You will also see that the Omega Trickler from Dandy Products really can drop one kernel at a time. It takes some careful adjusting of the drop tube to achieve this sensitivity, but the Omega really is up to the task.

A.J. recently acquired his Sartorius GD503 digital scale from Retail price is $899.99. A.J. reports: “I have to say the [GD503] is one awesome unit. I was loading my 260 with 42 grains of H4350. The GD503 is accurate to .005 (5 thousandths) of a grain. My Acculab was supposed to be accurate to .020 of a grain but couldn’t do that on a good day. This new scale can actually weigh an individual kernel of H4350, it weighs right at .025 per kernel. I weighed a small screw about 20 times throughout one day and every time I got the same exact reading. My load for my 260 now has a SD in the single digits and an ES of 10 fps is not uncommon for 5-shot groups.”

Having seen an actual reduction in his velocity ES and SD, A.J. is sold on his $900.00 GD503: “This thing is amazingly accurate. It repeats every time. The weight does not keep changing or growing like my Acculab VIC 123 or my RCBS Chargemaster. My loads have never been so accurate. Now I don’t have to wait for a Prometheus as I have something better for a fraction of the cost.”

If you’re interested in the Sartorius GD503, below is a video from that explains the features of the GD503 and shows how to set up and operate the unit to achieve the best results.

Strain-Gauge Scale vs. Force Restoration Scale — Responsiveness Test
This final video also shows the difference in performance between a strain gauge scale and magnetic force restoration scale (GD503). In the video, both scales are tasked with measuring tiny grains of salt, which are much smaller than extruded powder kernels. You can see that the GD503 responds more quickly when a few grains of salt are added.

Permalink Gear Review, New Product, Reloading 10 Comments »
August 13th, 2010

Pocket-Sized Scales for Reloaders

Ultra-portable mini-reloading scales have become popular with shooters who reload at the range. These can be small enough to fit in a shirt pocket. While not as precise as a bench-top unit, they can deliver read-outs to within 0.2 grains. These ultra-compact scales should prove very useful for any shooter that needs to load at the range. Additionally, they are affordable enough to be used as a back-up to a larger electronic or balance beam scale. Two models, one from MTM and the other from Acculab (Sartorius) have caught our attention.

NOTE: We haven’t yet been able to comparison-test these two scales with a laboratory scale to confirm the claimed levels of weighing precision and see if there are any serious calibration or “drift” issues. But we’ve heard no negative reports.

MTM Mini Reloading Scale — $30
The new DS-1200 weighs up to 1200 grains. MTM claims accuracy (resolution) to plus or minus 0.1 (one-tenth) grain. You can switch measurements among grains, grams, ounces and carats .The unit features a high-impact, plastic sensor cover that doubles as a large powder pan. The DS-1200 comes with a calibration weight, two (2) CR2032 Batteries, and a foam lined storage/travel case. Up to 1200 grain capacity with To save battery power, the large, backlit display shuts off automatically after 3 minutes. Here are sources for this bargain-priced new scale: Item MTDS1200 | $29.99

Acculab Pocket Pro PP-62 Mini Scale — $110
Sartorius, makers of the popular Acculab-123 scale and its Denver Instrument clone, the MXX-123, has introduced a new, portable reloading scale that is truly pocket-sized. The compact model PP-62 will work as a portable scale or a back-up for a benchscale. It measures 3.5″ long, 3″ wide, and just 7/8″ thick.

The Pocket Pro can handle a maximum weight of 1000 grains. Acculab claims resolution down to 0.1 (one-tenth) GRAM, which provides readability to 0.20 GRAINS. We like the fact that the unit runs on a single, easy-to-purchase AA battery. Battery life is up to 20 hours, if you turn off the back lighting on the LCD display. A sliding cover also protects the weighing mechanism during transport. The PP-62 offers easy one-button calibration with the supplied check weight.

Sinclair Int’l sells the new Acculab PP-62, for $119.95 (Item 10-6200). This includes battery, weighing pan, and 50 gram calibration weight. offers the PP-62 (with battery, pan, and check weight), for $109.95.

CONSUMER ALERT: On the web you’ll find other versions of the Acculab Pocket-Pro® Scales, priced at $45-$60.00. These are the PP-201 (photo below) and PP-401. Though these scales appear identical to the PP-62 (Sinclair item 10-6200), they are NOT the SAME. The cheaper PP-201 and PP-401 are only rated to one-TENTH of a GRAM. The PP-62 is RATED to one-HUNDRETH of a GRAM — roughly 0.2 GRAIN precision.

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