Heavier or lighter? Well, I was shocked to find out of 200 pieces of brass, I had 5 main groups. I divided them up in grain groups. Meaning if they were within a grain of each of other, they went into that group.

As far as which one to keep, I ain't no 1000 yard benchshooter, so I don't cull brass like they do. So I keep them all. I just won't mix the groups. I do notice that each step I do in the reloading process tightens up my groups little at a time. Its a hobby for me, so what the hey.