I am doing load development for my 20" .308 Win and am finding it definitely likes mild loads. In testing with Hornady 168 ELD-M, loads of 42 gr of Varget or 42 of RL-15 shot closest to POA and the tightest sub-MOA groups. Strangely, in my Varget testing, the POI DROPPED as load weight increased. MVs increased steadily as charge weights went up but POI dropped as much as 3 MOA from the 42 gr load to the 45.6 gr load. Strange stuff! MV with the 42 gr Varget is 2492 FPS. I loaded in .4 gr (about 1%) increments ending up at 45.6 / 2693 fps.
Brass is Win and OAL is 2.810".
43.0 of IMR4895 shot .768 MOA, 42.0 of IMR4895 shot .847 and 42.0 RL-15 shot .662. 42.0 of Varget shot .808 MOA. Any attempt to load hotter and I'm at 2 MOA or worse.
BTW, with the buffer weight, buffer spring, gas tube and extractor issues fixed cycling is perfect.