I worked for an aerospace company as an industrial photographer. In those days each step, each level of assembly of many of the products was documented by high resolution medium or large format cameras and these negatives became part of a permanent file maintained on each unit. One of my duties was to document every process of every department in the company, for training and quality assurance.

We had a calibration and certification department and I spent a lot of time working with them. I documented them checking, verifying and certifying the scales used to mix the various chemicals for our plating, etching and other processes. We used Ohaus Scales exclusively. Dial O Gram Beam Balances were used for less critical processes and Digital Analytical units for the most critical like gold plating. I remember quoting my grandfathers friend and the chuckles it got from the “CalTechs”. They explained to me that they went to the suppliers and and selected from their inventory the units that gave the same result when weighing the “standard” weight that they used back at our facility.
The supplier unpacked a number of units and powered them up at least 24hrs before testing. Out techs never touched this “standard” without wearing gloves and cleaned it with ether before each use. The scales were calibrated monthly and tweaked to the give the same result when they drifted. Several of the labs where these scales were located were “clean rooms” and all of the others were controlled temperature and humidity environments and the scales were plugged into into voltage stabilized and filtered power supplies and they still drifted, requiring adjustments by our Ohaus trained techs.

This long dissertation is to show the nature of the instruments we rely on.

In your case you are using an automatic dispenser to get close to your desired charge weight +/_.1gr and trickling to final weight on another scale accurate to +/_.02gr that you calibrate to your “standard” for repeatability. This is a good close loop system, just don’t add another scale or you’ll drive yourself batty.(I now own 5 digital scales that I have acquired over the years and none of them will give the same result when weighing the same check weight.)

We build rifles as accurate as current technology can deliver. We carefully craft ammunition to remove as many variables as possible. Then we turn all this precision over to the vagaries of an INFINATELY fallible human to aim and pull the trigger under the worst/best that Mother Nature, Murphy and the Range Fairies throw at us. It is a small miracle that we get groups as small as we do.

I will add that I have no complaints about the warranty – it went back twice and was replaced without question both times, although postage to the US (I am Australian) was at my cost.

Alan

Editor: Thanks for the head’s up. The units were available on Amazon when we released the story. You may be able to purchase directly from the manufacturer: http://www.myweigh.com but we don’t know the price. It looks like Digital Scales AZ has them for $159.99: http://www.digitalscalesaz.com/MyWeigh-Gem-Pro-250-Digital-Scale