I am one of those OCD guys that weighs every boolit after casting and separates into groups + or - .5gr. I tend to think that if I shoot boolits of roughly the same weight I will get better groups than if their is 2-3gr difference over the group.
The last batch of boolits that I cast were all weighed, placed in their own containers and powder coated different colors for each weight. After coating I went back and re-weighed just to see how much difference there was. Mind you that I am just using a little Frankfort Arsenal electronic scale to weight these boolits, but it seems to be at least fairly accurate. I was pretty surprised to find out that one coat of powder added about .5gr weight to each 45ACP boolit. Now I know that .5gr is not very much, especially on a 233gr boolit, but that was a surprise. I just keep thinking how much difference .5gr powder makes inside the case, but it makes very little difference outside the case. That is of coarse if you don't think about lubrication, leading, smokeless, less cleaning and better accuracy.
Fortunately I only greased boolits for a short time before I found Powder Coating. Thank You to all who have pioneered and perfected this technique. And thanks for sharing all of our experience with those of us with less imagination.