Lee Precision 90058 Perfect Powder Measurer (Red)

Q: What are your experiences with consistency between each charge with this measure?

Opinion, it is good enough for staying within the published load if you target the center, but if you want tenth of a grain precision at rifle weights, or want to max out the load, you will need additional trickler. Some real data, using VIHTAVUORI - N133, sample count=10 at each volume setting (reloading some .223, getting my reliability data and picking a volume for target weight) at 1.00 CC average was 12.95 grains, min weight was 12.8. max was 13.0 at 1.50 CC average was 19.54 grains, min weight was 19.4. max was 19.8 at 2.00 CC average was 26.14 grains, min weight was 25.9, max was 26.3 at 3.00 CC average was 39.09 grains, min weight was , 38.7 max was 39.4 On the worst case, 3 standard deviations was 2.6%, the rest 1.5%. 3 standard deviations about 99.7% of your production falls within this range. So if your in the middle of the specified range... more example say the spec is 22.1 to 24.5 grains, you go with 23.3 as your target and use the 2.6%, 99.7% of your production would fall between 22.7 and 23.9 grains. This is well within tolerances. However if you are trying to make high precision ammo 2.6% of target as 3 standard deviations is unsuitable and you should invest in a powder trickler to precisely top off a volumetric measure using this tool. If this is too mathematical, find an engineer or a math geek and show it to them. They will tell you I made unproven assumptions, but in general I am correct. 99.7% is assuming bell curve and perhaps I should have gotten more data at each setting. Data will vary with the specific powder used and the person using the tool, but this is probably typical results. Keep the powder reserve full. Be consistent with your motion and careful with your pan. Oh, plotting all the points on a graph of volume to mass made a pretty good best fit straight line, so it is fairly consistent.