Review of the GemPro 250 Scale (from My Weigh)
SUMMARY: This review gives high marks to GemPro 250 scale from My Weigh. It offers 0.02 grain resolution, good enough to trickle kernel by kernel. At just $165.49, the scale is quite affordable. The GemPro 250 comes with a lifetime warranty for American buyers. As this scale weighs more precisely than popular digital powder scale/dispensers, you can use the digital dispenser to throw a “close” charge and then fine-tune your load with the GemPro, kernel by kernel.
by Bill Schnauffer (aka Cover Dog)
The Importance of Precise Loads for Long-Range Shooting
The reloading scale is the life blood of anyone’s loading bench. It’s used for everything from weighing powders to cases or bullets and yes even primers. I would have never considered weighing primers but that is one of the many things I learned the weekend of May 20-22, 2011 at The Original Pennsylvania 1000-Yard Bench Rest Club’s Bench Rest Instructional School. All aspects of reloading for 1000-yard BR have to be identical. Your brass, bullets, powder and primers all have to weigh the same, for all your sighters and your 10 record shots, if you want any chance of being competitive. This can only become a reality if your scale is up to the task. Everything you do when shooting at 1000 yards is magnified 10x and your scale needs to be above all else, accurate and repeatable.
I thought that a scale accurate to 1/10th of a grain was good enough. Not so in the long range BR game. Scales need to be accurate to at least 5/100ths of a grain or better if you can afford it. This prompted my search for such a scale.
GemPro Is Half the Price of Denver Instrument MXX-123
I have read reviews for several of the better scales used for reloading including the Accu-Lab VIC 123 (Accu-Lab ceased operation Dec. 31, 2010) and its predecessor the Sartorius AY-123. The scales are identical just repackaged and with a new name and color. The scale is accurate to 2/100ths of a grain, but is also a scale that many felt was affected by RF interference and the slightest air movement made it drift. This was due in part because of the strain gauge technology that is used in the manufacture of this scale. And with parts not readily available, the lead time for one is you want it is over 20 weeks. The Denver Instrument MXX-123 also had a good review but like the others above, it’s into the $320 price range. And this is out of reach for many reloaders.
This now brings me to the My Weigh GemPro 250. It uses True-Division German HBM sensors and professional components in the manufacture of this scale. It has a 50 gram weight capacity (771.72 grains) and accuracy down to 2/100ths of a grain. It features seven (7) weighing modes as listed below. And with a retail price in the $165.00 range, this is a scale that most reloaders could afford for their reloading bench. And you won’t be pressed for room on that bench. The scale is very compact, measuring 5.25″ X 3.75″ X 2.5″.
NOTE: There is also a GemPro 500 which has a weight capacity of 100g (1543 grains) but only has accuracy down to 5/100ths of a grain.
Testing and Evaluation
I decided to give the GemPro 250 a try. Several days after I placed my order, Big Brown arrived. As I started to unpack the scale my heart started to sink and the first words out of my mouth were “boy is this thing small, hope it wasn’t a mistake”, only time will tell.
Included with the scale was a plastic travel case that housed the accessories. They consisted of an AC power supply, ASTM class F2 calibration weight, weighing pan, plastic tweezers and a vibra-kill pad. The scale also has a built in circular bubble level, four leveling feet, hinged protective windscreen and a stainless steel weighing platform. If you load at the range, you’ll be glad to know that it also runs on four AAA batteries. Information sheets that came with the scale stated it takes the load cell one hour to come up one degree in temperature when plugged in and turned on. Instructions recommend giving the unit a 24-hour warm-up before use.
Scale Calibrates Rapidly
After leaving the scale on for 24 hours (my scales are always up and running), I placed the ASTM class F2 20g calibration weight on the scale after setting it to calibrate. After about 3 seconds it stopped its calibration and read 20.000g exactly what the calibration weight was supposed to weigh. When converting grams to grains you need to multiply by 15.4324 or with this scale you can just scroll through the seven weighing modes until you come to grains. Its actual weight is 308.65 grains but since this scale only reads to 2/100ths of a grain the 100ths digit must always be an even number, so it reads 308.64 grains.
For the next several minutes I started weighing everything I had in front of me. Bullets, brass, loaded rounds all were gathered up and weighed so I could get the feel for the GemPro 250.
I set the calibration weight on the scale between every one of the 30 loads I weighed. Only once did it vary from the 308.64 grain reading when it moved up to 308.66 grains.
I wish I had at my disposal a scale more sensitive than the GemPro 250 to double check its accuracy. Scales that read to 1/100th of a grain are out of my price range, and cost from $2000 for the Citizen CX265 to $4065 for the A&D Phoenix GH252. I purchased a PACT Digital Scale in late 1994 and to this day it has been my “go to” scale. In 2002 I sent it back to PACT to have the infrared port installed so I could purchase PACT’s infrared powder dispenser. I have used the PACT Scale/Dispenser as a team for the last 10+ years for all my reloading needs. So now with the GemPro 250 on my bench it was time to see how “accurate” my reloading with the PACT combo has been.
Editor’s Note: In this review, the GemPro 250 is used to confirm the weight of powder throws from a PACT digital dispenser. However, the reviewer did not have a laboratory-grade scale to test the displayed weights from the GemPro 250. We have another GemPro 250 on order from Amazon.com. When it arrives we will do a comparison weighing test, using a Denver Instruments lab scale as the control unit.
REAL WORLD TESTING
Double-Checking PACT Dispenser with GemPro 250
For the first test I used Reloder 15 (RL15), a course, long-kernel powder. After calibrating both the PACT scale and the GemPro 250 I set the Pact Dispenser to throw a charge of 27.7 grains. During the throws, if the PACT scale read 1/10th over/under, I didn’t make any correction. I just waited until it stopped dispensing and the transferred the charge in the pan to the pan in the GemPro 250.
Below are the results of those 10 thrown charges:
27.76 | 27.94 | 27.80 | 27.84 | 27.92 | 27.88 | 27.76 | 27.88 | 27.78 | 27.78
Note: As measured by the GemPro 250, none of the PACT throws hit the 27.7 grain mark exactly — all throws were slightly high. The total spread from lowest (27.76) to highest (27.94) throw was 0.18 grains and the spread from the 27.7 target weight to the highest dispensed charge was 2.4 tenths of a grain HIGH. I’m sure this could cause a little vertical at 1000 yards.
For the next round of tests, I used IMR 8208 XBR. Compared to RL15, the kernels of 8208 are shorter in length and smaller in girth. Using the same parameters as with the RL15, here are the results of 10 thrown charges with IMR 8208 XBR:
27.78 | 27.80 | 27.78 | 27.82 | 27.78 | 27.84 | 27.80 | 27.74 | 27.78 | 27.74
Once again, not one of the 10 dispensed charges were right on the mark according to the GemPro. Again, all thrown charges were slightly hight.The range from target weight to the highest was 1.4 tenths of a grain, and the total variance from 27.70 grain target weight was 0.14 grains.
The final powder tested was HS6. This is a spherical powder which, by most accounts, meters very well. With the same procedures in place here are the results for HS6 weighed on the GemPro 250:
27.76 | 27.74 | 27.74 | 27.78 | 27.68 | 27.74 | 27.70 | 27.74 | 27.68 | 27.70
As expected HS6 did very well in getting close to the 27.70 target and hit it on several throws. The total variance from the 27.70 target Averaging 26/100ths over for the 10 charges thrown
PACT Performance Re-Evaluated
Only able to read to 1/10th of a grain, the PACT dispenser looked to be nearly perfect with the HS6 powder. But when checked with a precision scale capable of reading to 2/100th’s of a grain, I found that the PACT still threw loads that were higher than what was programmed. I will still use my PACT to dispense my loads one grain short and then trickle in the last few kernels with the scale pan sitting on the GemPro 250.
The GemPro 250 is small, compact, portable and able to deliver repeatable accuracy to 2/100ths of a grain, time after time. That is all that one can ask of any scale. There is one last important thing to mention. The GemPro 250′s express warranty is LIFETIME (for domestic buyers) or 30 years for International Customers. A lifetime warranty is unheard of in the electronics business. I guess the people at My Weigh know what they have and are willing to stand behind it. If it should ever need servicing the My Weigh service center located in Phoenix, AZ will repair your scale and have it back to you in two business days.
- GemPro 250 Digital Scale on Sale for Just $145.00
- Improved View for Balance-Beam Scales
- Better View for Balance-Beam Scales
- Digital Scale Comparison: GemPro 500, AY123, Sartorius GD503
- Weight Drift on Digital Scales