Randy obtained a new DPMS LR-308 G-2, with 20" Barrel. He decided on 165 gr Hornady boat tail spire point, and I said let's try IMR 8208, since it worked so well in my rifle that is similar. Simmons 4-12X with a duplex reticle. I checked zero at 100 with a copy of the lowest charge, then held the point of the heavy post on steel at 300 yards, since that distance from center of the reticle was exactly equivalent to 1.0 Mil. The bullet impacted low from center, but I knew it would keep us on paper, so that was my hold, on the "+" every shot.
I do have a Razor 85mm spotting scope with a fixed 30X Mil eye piece. Randy stayed on the spotter while I shot 3 rounds through his rifle. Then I would get behind the spotter and "map" where each one landed, POI vs. POA in tenth of Mil. And write the powder charge next to the impact on the map. Photo below explains it well. We never drove to the target through 15 shots. We stayed parked in the loading room, in the shade.
After the shooting, I drove out and retrieved the paper target. The bullets had been colored and labeled accordingly, so we knew what color bullet hole was which charge. We had a clear node at 40.0, 40.3, and 40.6 gr. Those three grouped 2".
I told Randy usually the one in the middle of the node is the winner of the group shoot, but let's not skip a charge. Well 40.0 shot 1 1/2" tall and 4" wide at 200 yards, then I shot 40.3" gr.
Height is more important to me, but it was .58" wide. I just loaded the wrong photo here. That's 1/4 MOA in a plain vanilla DPMS. Will it do that every time? No way, but we did find the BEST powder charge after having shot only 22 rounds. This process took a grand total of 2 hours. Since Randy brought his press, and components prepared to load a group within the node, immediately after shooting the ladder test.