Modern lever-action data starts around 1800fps with that weight of bullet, and will push those bullets way too fast... you will likely get leading. My suggestion is to try a powder like IMR4198 and keep those bullets at or below 1500fps.
FYI, Hodgdon's online data has 325 and 350grn data for modern levers... which means jacketed bullets, because of the velocities. If you look at their Trapdoor data, they have a data set for the 385grn cast bullet... that would be more down your alley. You could easily start with the 385grn bullet data, and adjust for your slightly lower bullet weight.