Thanks all for the input. I had a couple objectives for this endeavor, to learn more about developing a rifle load, and to see what else I can coax out of my RRA AR. I know it's still way more accurate than I am, but hey, it's fun trying to find the best load, and learn what I can along the way.
I thought I would focus on testing OALs next. Here are my results to date. It looks like the OALs to focus on next are 2.280 and 2.320. The round outside the group @ 2.320, I may not have followed through with the trigger, and may have pulled it slightly. It was brisk and windy today. I'll work up some loads around these two next.
5 rounds on each target, round robin, 100 yds, 25.0 gr Varget, 69gr SMK, PMC brass, CCI #400 primers.
The rounds at 2.360 were too long to be fed from mag, so they were dropped into chamber, pushed halfway in, and then released the bolt. This was the max OAL I selected as the distance to the lands is right at 2.365 All others were single fed from mag.
Tested 12/31/11
OAL / Spread
2.245 / .998"
2.250 / .989"
2.255 / .848"
2.260 / 1.019" (normal OAL)
Tested 1/2/11
OAL / Spread
2.260 / .843"
2.280 / .679" (4 @ .297" .283 MOA)
2.320 / .894" (4 @ .534" .510 MOA)
2.360 / 1.605"