Just a thought, but a 180 grain lead bullet with a wide flat meplat, driven at "standard" .38-40 velocities, sized to fit the throats and soft enough to expand will be accurate without leading and have plenty of moxie for ripping the soul out of a deer. An old hunting pard performed that trick with boring regularity, utilizing a 1920's-vintage Colt New Service. 8 grains of Unique was his go-to load, but don't quote me on that.
