Shooting benchrest Schuetzen at 200yards, I disagree that sorting doesn't make a difference. Those that do, win. Those that don't, don't win. Mine are sorted into 0.2gr increments, and, having tried the same experiment as GB, benefit from this sorting.
Someone mentioned that at 50yds or less that sorting doesn't make a difference..? I agree with that, but for long range it is just one more variable that you can take out of your "system". If you're looking to chew bits off of your longer range BR group, brass prep and bullet sorting are the cheapest ways to make your ammo consistent. -FOR BULLSEYE SHOOTING with my 38, I never bothered and never will.
"...for some reason some were several grains heavier..." I had a theory on this and I was able to verify it using my lathe. The mould blocks were not closed tightly and resulted in an out-of-round bullet which was overweight.