I own both an original 2nd Model S&W Russian, and 2 Ubertis... I shot both today, the original with Black Powder loaded 44 Russian ammo, and one of the Ubertis with Smokeless (231) loads.
I cleaned the S&W in about 10 minutes or less, totally spotless.
I cleaned the Uberti in somewhat over a half hour, using a Lewis Led Remover and wire brush in the bore and chambers, and razor blade scraper (on the breech face). Short of using a power drill motor, cleaning smokeless residue is a real chore, if you want it "really" clean, including the carbon rings in the cylinder and lead in the bore.... I have yet to see lead in a black powder bore. And I consider 231 to be a fairly clean burning powder.