Well,have you give it any thought that the rifle just doesn't like that bullet..

I had a win.30-06 that would not shoot a boat tail worth a dam..But the flat
base bullet was a different story..I finally admited defeat and just got more
flat base's and left it at that..Rifle twist-MV-Barrel Crown-amount of free
bore if any,powder type-all can be a major factor here...