Hey Oahu. Nice guns. Very accurate shooting. Thanks for the response. These Lancaster smooth oval bores are in their own world. Normal rules do not apply. Paper patching is a must. N for B does --NOT-- give the bullet rear-end that "bump up to bore size" that black powder does. Sherman Bell's articles are fascinating, as are Ross's, and I have benefited tremendously from them. The Lancaster catalogues call for a 350-grain bullet and "about" 100 grains of black powder for his 1880s .450 BPE. This gun was made in 1888, and the ledger loading instructions clearly state two wraps of paper and 100 grains of powder. Adding complexity is the bore's taper and gain twist. It is a real project. Hang in the Ten Ring, man! :-)
Huvius, that's excellent advice. Last week was the first time I started doing that, and there's no column in my data tabs to account for it. The challenge with that slight fit is this is a hunting gun, and loose hand-fitted bullets are not practical in the field. Whatever load works best, assuming at least one is finally, consistently good enough at 100 yards, will be my hunting load. Winter in Pennsylvania is pretty harsh. Bullets have to survive in that environment.
Edit: Oahu, all of my loaded cases are filled to the top with Dacron, covered by a .060" fiber wad, on which the patched bullet is seated.