load for 300 grain
Thanks for the reply. The load is 118 grains of RL12. They chronograph at 3162 +- 25. The basic problem with most of the explanations is making the group size consistent with the extreme drop. It can't be random else the group size would scale with the difference in drop. The fact that there is little (<1.5") spread horizontally tells me that it is not barrel vibration. That would have to be basically circular since the orientation of the bullet relative to the bore is random. It can't be difference in drop since the drop is 16 times time of flight squared. For 100 yds this is only ~16*(300/3000)*(300/3000) = .16' =2.4". It can't be barrel rise since this would be more for the heavier loads. That seems to leave just a barrel droop as with a fly rod. I haven't had time to finish that calculation yet.