I never had any luck with them in a 338 Edge which I found odd because many other calibers and cartridges loved the ABs and were very accurate for me.
I am shooting the 300 Accubond .010" away from the lands out of my 338 RUM using RL-33 and getting consistent 1/4 MOA accuracy at 2780 fps.
Generally speaking Accubonds have always shot pretty well out of all of my rifles, but I did get a bad box of .308 210 ALR's that would not shoot better than 1.5" out of a proven 1/4 MOA 300 win mag.
Have you tried shooting a different box/lot of 300 Accubonds?
it might be worth trying the Berger Bullets seating depth test , I wouldn't be surprised if for whatever reason they may want more jump than you have tried so far
maybe, I load at least 6 different accubond weights including the 338 300 gr in 4 calibers, 10 different guns and all have been fairly easy to get under moa most well under for three shot groups , have you tried shooting at 200 yards ?
I was thinking that possibly they need some room or yardage to stabilize since they are a long bullet but honestly I really have not seen that with my savage 338L, you might have to get it checked out or try some different bullets some guns are finicky on what they like I guess I have been lucky to have not seen that much ,other than shooting bullets that were not correct for the barrel twist in a couple of guns