Denver Instrument MXX-123 Test
Digital Scale Proves a Rock-Solid Performer
MXX-123 Delivers Single-Kernel Accuracy for $275.00
The Denver Instrument MXX-123 scale is rated to .02 grains (two-hundreths of a grain). A single kernel of Varget powder weighs just about .02 grains. Until recently, to measure powder with this degree of accuracy, you had to buy a milligram-rated analytical balance that could cost $1000 or more. We were excited to learn about Denver Instrument's new scale, particularly since it costs just $275.00 plus shipping. We wondered, however, with such a low price, could the MXX-123 match the performance of much more expensive scales, delivering the precision reloader effective single-kernel accuracy? Would sensitivity to drafts or "drifting zeros" prove to be problems in actual use?
In tests carried out by James Phillips and Jerry Tierney, we've found that the MXX-123 is an exceptionally good unit. It delivers on its promise of repeatable .02 grain accuracy, while remaining stable over time. It is more accurate and repeatable than balance-beam scales, and its measuring accuracy rivals the much-respected Prometheus powder measure. It is SO sensitive, however, you do have to be mindful of the slightest bit of breeze in your loading room. Bottom Line: the MXX-123 delivers all the accuracy a reloader can use, at a cost that is one-third or one-fourth of milligram laboratory balances. If you want to load with single-kernel precision, the MXX-123 will do the job quickly and reliably, at a very reasonable cost.
|MXX-123 vs. DI TR-203D Lab Scale ($1100.00)|
Report from James Phillips:
Here are my final test results for the MXX-123 using my TR-603D analytical balance with milligram resolution. All charges were exactly 30.51 grains of Varget weighed across a TR-603D scale. I picked this charge weight on purpose as I knew the MXX-123 scale only weighs in .02 grain increments whereas the TR-603D resolves to .01 grains. I wanted to see how the MXX-123 would handle a "true weight" in-between its resolution range. No problem, the MXX-123 sometimes showed 31.50 and sometimes 31.52--in either case it was still "correct" within one kernel. I did observe .08 grains drift from zero after the MXX-123 sat overnight and I retested the next night. To correct for that, all I did was zero it out and went back to weighing the previous charges. The drift is of no concern if you re-zero prior to each daily session. All my scales exhibit some drift and at times will be off way more than the MXX-123.
Tweaking for Best Results: I did go into the MXX-123's software and changed the enviromental settings to "Very Unstable" so that the read-out would not float around at the slightest breath of air or someone walking into the room. This keeps the scale from being too sensitive to air drafts and folks walking around the room. (I did the same to my TR-603D scales). The software adjustment just gives the scale more time to lock-in on the real weight if this makes any sense.
CONCLUSION: In addition to the tests recorded below I check-weighed the 20-gram test weight with the MXX-123 numerous times, and the MXX-123 was "dead-on" each time. With 31.51 grain charges set by the much more expensive TR-603D, the MXX-123 was within +/- ONE-hundreth of a grain EVERY time during immediate weighing. Even after four hours, the MXX-123 held this accuracy 90% of the time, and never was more than .03 grains high, still less than two kernels. (In 3 of 30 4-hour-delayed tests, it registered 30.54 grains.) So, with Varget, it is fair to say the MXX-123 delivers single-kernel accuracy, and it is very consistent over a long series of measurements. Overall, my findings are very positive and I can only say I wish they had the MXX-123 when I purchased my TR-603D! I could had saved several hundred dollars and been just as happy with the MXX-123 as my TR-603D scales.
|Denver Instrument MXX-123 vs. TR-603D Weight Tests|
2 hours later
4 hours later
|MXX-123 24 hours later|
Re-zero (.08 gr drift)
|MXX-123 vs. RCBS 10-10 Beam Scale ($140.00)|
|Report from Jerry Tierney:
First, let me make some general observations about the MXX-123. There were several tenths of zero drift in the first hours of “burn in”--12 hours of "power-on" time before I calibrated and started measuring. I observed very small zero drifts while measuring--about 0.06 grains--but that doesn't seem to affect the reading by that much. I have NOT seen any effects on measurement caused by lights, telephones or ambient temperatures (50 to 75 degrees). Now on to the tests...
Many reloaders rely on a balance beam scale. Balance beams are slow, but they do work better than some of the under-$200 digital scales. I wanted to see how charges I weighed (as precisely as possible) with my 10-10 scale, stacked up when measured by the Denver Instrument MXX-123. To start, I loaded 50 charges of Varget with the balance beam scale set at 33.5 grains. Every charge was exactly 33.5 grains, at least according to the 10-10 scale.
I then weighed each load on the MXX-123. The max and min loads were weighed several times, checking zero, and checking with a 20-gram test weight between each weighing. All were within +/- 0.02 grains. The 50 charges I had weighed out on the 10-10 balance beam showed over two-tenths variation, when re-weighed on the MXX-123. The high was 33.72 grains, while the low was 33.48 grains. This gave a spread of 0.24 grains. I knew I was getting plus or minus 0.1 grains with the balance beam, and this confirmed than my extreme spread was a bit more than two-tenths of a grain.
|50 Charges with 10-10|
set at 33.5 grains
|MXX-123 weight||Total Charges||Percent of Total|
|MXX-123 vs. Prometheus Dispenser ($1250)|
|Report from Jerry Tierney:
I use a Prometheus machine to dispense and measure my powder loads. I was curious to see how my powder charges, as thrown on the Prometheus, measured out on the MXX-123. I loaded 50 rounds of Varget with the Prometheus beam-scale set as 47.5 grains. For each powder charge dispensed by the Prometheus, I weighed the loads on the MXX-123. The max and min loads were then weighed several times, checking zero, and checking with a 20-gram test weight between each weighing. All these were within +/- 0.02 grains. Among the 50 charges, the low (as measured by the MXX-123) was 47.42 grains, while the high was 47.56 grains. That showed a total spread of 0.14 grains. I thought my Prometheus-thrown charges would have an ES of well under 0.14 grains, so these results were surprising.
CONCLUSION: The MXX-123 is a good scale. I would recommend it. However, please note that the above measurements are more of an indication of my loading techniques and not the accuracy of either beam.
|50 Charges with Prometheus|
set at 47.5 grains
|MXX-123 weight||Total Charges||Percent of Total|
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|USER COMMENTS by Recent MXX-123 Purchasers
I received mine yesterday. With a limited amount of playing with it I can tell you this: Warm up time is practically nil. It was less than three minutes for my unit. Fluorescent lights directly over the unit had no ill effect what-so-ever. A big plus for me since I my reloading room is full of fluorescents.
Drafts were not a problem since my reloading room is below ground level with no windows open. However the balance is sensitive enough that a couple of times I noticed a .01 fluctuation due to my body movement.
As Dennis notes, unlike the Acculab 123, the MXX-123 has no flip-up cover, but don't let this stop you. A small clear Tupperware-type storage tub from Wally-World when turned upside down over the balance affords probably better protection than a hinged cover anyway, and keeps dust off the entire balance in the process. Even if mine did have a hinged cover I'd take this precaution for the $250+ investment. Set-up was a snap, even for one as technically challenged as I. I have mine running through a surge suppressor, but I'm not sure that's even necessary.
I re-weighed some new 6BR brass that I had previously painstakingly weighed on my RCBS 10-10 sorting it into one grain batches. Those I re-weighed were between 126.0-127.0. With the MXX-123 I could easily re-weigh all of that batch (107 pieces)in no time at all. About as fast as you could place it and remove it from the balance. A HUGE improvement over sweating over the 10-10! In fact I plan to reweigh all 500 pieces. It's that simple. Powder charges were easy. I threw a couple of tenths light with my Harrell's measure then dropped a few kernels to bring it up to weight. Piece of cake. Scary it's so easy. So far I'm real happy with the unit. Dennis and I will keep you informed if any glitches develop that we aren't aware of yet.
Bargain Dust Cover--OK, all you potential MXX-123 owners looking for the perfect cover to protect your balance sitting on the bench from dust and heaven forbid accidental knocks and drops. Go to your local Wally World and plunk down $3.12 for a Sterilite ShowOff plastic storage box, item #1894. It's clear with a blue removable lid that you can discard. Turn it upside down over the MXX-123 and there's your protection for when the balance isn't in use. It's just big enough that it doesn't touch the balance on any side, and tall enough to clear the draft ring by a couple of inches.
Dennis (Flatlander) Selfridge:
The MXX-123 doesn't have a flip-up hard cover. It does come with a glass ring that fits around the edge of the pan that's supposed to deflect drafts that might upset the scale as it's weighing. The ring is only about 1" tall, so it doesn't interfere with reaching over it to pick up the scale pan off one of my Redding balances that I've been using on the 123. I found it easy to level the scale (it has a built-in bubble level) with its adjustable feet, and it took only a few seconds to do the initial calibration, using the supplied calibration weight. I'm very pleased with the ease of use, its stability, speed of settling on a reading, and the precision of having a scale capable of resolving a single kernel of powder.
However, in my drafty old house (built in 1909), there are pitfalls to having a scale with this much sensitivity. Even in the basement, there are air currents strong enough to upset this balance when the wind blows as hard as it's been blowing for the past several days. We had strong southerly winds over Thanksgiving and Friday, 20-30 mph with higher gusts. Then all day Sunday, blizzard-like conditions with winds of 45 mph with gusts to 50-60 mph have carried over into today, making it impossible to use the scale. This isn't a criticism, though those of you with homes more air-tight than mine might mistake it for such. Neither the Dillon nor Lyman units function well under these conditions either. The wind's going to have to die down to a more typical western Kansas breeze of 10-15 mph before I'll attempt to do more loading.
The one evening when there wasn't much wind, it seemed to have warmed up or stabilized within about five minutes, and drifted off zero only once in the time it took to weigh out 25 charges of N560 for some 6.5x55 ammo. Re-zeroing takes only a second or so. The display is quite a bit larger than that of the Dillon, and is backlit, making it very easy to read.
You will want to have the owner's manual available during setup though, as I found it a little difficult to interpret some of the display's rather cryptic messages when I toggled the unit of measure from grams to grains. This unit is capable of several different functions that most reloaders will never use, but these are well-covered in the owner's manual.
Setup, unit of measure selection, and calibration are easily accomplished, and for those of you who want to be able to just unpack and start using it, [the manual has] two or three pages covering those items.
So far, I'm very pleased with the MXX-123, and would certainly make the purchase again. I feel it's quite an improvement over my old ('92) Dillon Determinator--nearly as big a step up as the Dillon was over the beam balances I'd been using for 26 years. Hopefully, it'll be as durable as the Dillon has been. Time will tell.
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