I shoot a Win/Miroku 1885 and find it a tackdriver with Marbles aperture sight. Bullet is Mountain Mould 330gr GC (nominal) sized .413 and lubed with Rooster HVR. No leading at all.
Powder is Somchem S365 ( stick powder / extruded) very similar burn to H-4350 with 55.0gr delivering approx 1910fps average. Fill is about 99%.
Also have a Ruger #1 in same .405 cal. Hope to make some time to see how shoots above load.