After throwing easily 1k+ loads from my Chargemaster and trickling up on an A&D FX120i, the inaccuracy of the Chargemaster (and likely any other dispenser/scale in that price range) became clear. I ran the four tests shown below and concluded that:
1) Chargemaster accuracy was improved by changing parameter S_S from 128 to 255. This allows the scale 255ms to settle down before the microprocessor considers the scale's weight final.
2) The Chargemaster was no more accurate with fine powders than my Hornady powder measure. The chargemaster is better with stick powders, and of course easier to change target weights.
3) The tests below can't possibly be definitive. But the results felt the same as a thousand throws done earlier while using the the Chargemaster as a Lee Dipper and trickling up. The Chargemaster just wasn't accurate enough for my purposes. YMMV.
Chargemaster with H335: 48 loads, 45gr
Loads within +/- 0.06gr of target = 33 or 68.8%
Loads within +/- 0.1gr of target = 41 or 85.4%
Loads not within +/- 0.1gr of target = 7 or 14.6%
When missing the target load, by more than +/- 0.1gr, how far off were they?
+0.5gr, +0.12gr, -0.12gr, -0.14gr, -0.16gr, -0.32gr, -1.04gr
Chargemaster with H335: 50 loads, 40gr (after changing Parameter S_S from 128 to 255)
Loads within +/- 0.06gr of target = 43 or 86% (33 or 68.8%)
Loads within +/- 0.1gr of target = 49 or 98% (41 or 85.4%)
Loads not within +/- 0.1gr of target = 1 or 2% (7 or 14.6%)
When missing the target load, by more than +/- 0.1gr, how far off were they?
+0.16
Hornady PM with H335: 50 loads, 40gr
Loads within +/- 0.06gr of target = 44/88%
Loads within +/- 0.1gr of target = 48/96%
Loads not within +/- 0.1gr of target = 2/4%
When missing the target load, by more than +/- 0.1gr, how far off was the Hornady?
-0.12gr, -0.12gr
Chargemaster with IMR4350: 50 loads, 50gr
Exact: 8, 16%
Low: 24, 48%
High: 18, 36%
+/-0.02gr: 19, 38%
+/-0.06gr: 41, 82%
+/-0.1gr: 43, 86%
>+/-0.1gr: 7, 14%
The charges >+/-0.1gr were all high: 5x0.12gr, 0.18gr, 0.20gr