My NewEnglander likes short conicals like the Lee 250 or 325 grain REALs with 80 grains T-7 ffg.
Haven't tried T-7 & PRB in it, but it seems to favor heavy charges of BP with a PRB. (90 - 100 gr ffg Goex)
PRB accuracy is acceptable, but not great out of it.
I always used a 325 grain Lee REAL for my #1 hunting load, but bought a 250 grain mould this winter and my only range session with them in my newEnglander looks like they may soon replace the 325 grain. It will take a couple groups with each one on the same day to determine which is most accurate, but they will both shoot very well.
Oddly enough another very accurate projectile in mineis a 350 grain cast .458 bullet in an MMP orange sabot.