I've sold many LFN molds for 45 ACP, in weights from 200 up to 260 gr, with this the first complaint of poor accuracy. Most say the 220 and heavier weights are superbly accurate, a few say they get good accuracy but not match grade. No one has told me about problems with any powder that worked with other bullets. SO_______.
If you are not used to using gas checked bullets, one possibility that may be causing you problems is out of square bases. If using a Star sizer and pushing them through base first, this is a very likely problem. The shorter the bullet, the more out of square based throw accuracy off.
If your guns shoots other cast bullets accurately when sized 452, I don't believe diameter could be a problem.