Oh, I just thought of something else that could be a factor in the inaccuracy. Have you ensured your bullets are aligned properly when you seat them? I've noticed that if I don't flare the case mouth enough, the bullets are sometimes either canted slightly (more of an issue with the FTX) or the case is bulged only on one side as if the bullet is slightly off center. Unfortunately, I never shot my old 460 at far enough ranges to see if either issue would affect accuracy, and I haven't shot my newer PC 460 enough to know what makes it shoot well or not, so I don't have any real data to support this theory.