My next attempt at trying to better my load l will weigh the bullets individually and use bullets that only weigh exactly the same (This is my next trial to achieve better than 0.38" at 100 yds). Some people even weigh the brass and use only bench rest primers.
Weighing the bullets have no appreciable effect at 100 yards in my experience, better to sort bullets base to contact point on the ogive. Then be sure to have all the seating depth exactly the same, like to the .001". I weight sort cases, however, the important factor is case volume. To find case volume in a pita, so I just lot them out into similar weights and call it good. Neck tension is also very important. You want all the bullets seating, thus releasing, at a similar force as you can get them. Annealing helps in this.
At 100 yards barrel tune is the factor that make a lot of the difference. Barrel tune in a mix between charge weight and seating depth. Find your optimal charge, then tune it out by seat depth.
At longer range, the velocity spread will play more and more of a role, as distance increases, the more important it is to have ES/SD as low as possible.
You aught to try OCW by Dan Newberry. Save a ton on time and components finding an optimal load for your rifle.

I found this load using a grand total of 25 rounds, granted, I have been using this method for a while and I know what to look for. Dan's sight also has a forum to help with interpretation of shot groups. That helps a lot.
This same load fired at 200 yards stayed easily within 1.5", mostly due to my poor shooting skills, and stayed within call at 600 yards, no problem. I am sure a better trigger puller would be able to keep shots well within 1/2 an MOA at 600 yards with this load.