I have a 500 3 1/4" BPE that I have worked up a good NFB load for using 440 grain Woodleighs. Problem is, with the original sights it shoots 6 inches high at 50 meters. Tried multiple powders, and varying velocities, but it never really changes more than an inch.
The 440 grain bullet seems to be the excepted weight for the NFB loading with this cartridge. However every vintage black powder loading I have come across (Eley and Kynoch) for the 3 1/4" has used 480 grain bullets.
Before I waist my time and money experimenting with heavier bullets, I would like to know if anyone has had similar problems and found a cure. Think the extra 40 grains would lower the POI that much? I can of course change the front sight, but I really don't want to do that.

Thanks,
Josh