I don't know much about that but I weighed a box of Hornady .490 balls last night. There were only 95 in a new box of 100. They ranged from 177.3 to 178.5 gr. I divided them into 2 groups. I ended up with 42 that were between 177.3 and 177.9 and 53 that were between 178 and 178.5. He thinks you should keep them within 1/2 gr of each other.. For hunting it doesn't really matter. For target or Rondy shooting it can make a difference. The biggest thing I found out from the info was how much difference there is in measuring patches. Some compress a lot more than others. Mic-ing them regular and compressed can make a big difference in accuracy. Oh well that's enough. You can wait to get the mail to find out the rest