I have just begun to shoot my newly built 6.5-284. Broughton 5C barrel. 8 twist. 26" long. Cleaned it, shot once, cleaned it, shot once, cleaned it, shot 3, cleaned it, shot 15. Using 7828, I'm starting with 50 grains. First load was touching. Shot a .457 group. 2nd load .030 off and shot .576. 3rd load .060 off and shot .331. All groups shot @ 100. Now I'm going to load 50 more at the .060 jump and go have fun with it. I called Tim @ Broughton and he said the barrel should start to settle in around 75 rounds and also reach its top velocity. Then it will be ladder test and final load tuning.
Lapua Brass
Fed 210m
143 ELD-X
50 grains 7828SSC
2640 FPS
All virgin brass so far and will continue until 75 down the tube. The load is slow but will pick up the pace the further I get down the line. Plan on adding powder in final load development. Should be around 52.5-53 grains. Hoping for 2900-2950