What increments do you use when sorting H2O case Volume

[Chas1]

I'm measuring 338 Allen Xpress Case volume using water and as an example a case holds 120grs of H2O and another holds 121.4grs and so on. My question is what increments are you sorting them into ? Are you sorting them into 1grs or 1/2gr or 1/10gr etc ?

 

[yotayoda]

I sort them into a group within half of one standard deviation of the mean. Then use the remainder for plinking/misc.
So I weigh 50 or a 100 of them. Determine the Sd. Determine the mean. Split the Sd in half. Add that number to the mean for the high, subtract that number for the low. Done. I don't know that there's really any rhyme or reason, but it's what I do.
Back when I didn't buy huge lots of brass, I would weigh 50 or 100 of them and pick the range most likely to give me the number of "match" rounds I wanted.