Is that IMR or Hodgdon's powder, buckstix?
I just noticed in loading the .45/70 Lever guns with 350gr., there is quite a difference between them in both starting and maximum loads.
I see Hodgdon lists 49.0gr. H4895 in the .450 3 1/4" Modern Sharps chambering at 1,903fps. They did not list IMR4198 in this ctg. length.