I have been informed that shooting 45 Colt black powder ammunition in lever action rifles allows more residue to enter actions because of its brass being thicker/tougher around case mouths compared with 44-40 brass. 45 Colt brass does not seal chambers as effectively at black powder pressures as more flexible 44-40 brass.
Shooting 45 Colt with Starline brass and Goex FFg, as best you can, please identify the rifle lever action - among Marlin 1894, Rossi 1892 Winchester reproduction, and Uberti 1873 Winchester reproduction - that is easiest and/or most straightforward to clean-maintain. My black powder experience has been muzzleloaders and Shiloh Sharps 1863s. Comparatively, these have fewer parts, no feed or extraction mechanics - in essence, not many places into which black powder residue can squirm.