I put somewhere between 4,000 and 5,000 rounds of cast lead reloads with 231 through my 4" Model 19 over a period of years with no cleaning.
Nary a problem.
It was pretty cruddy by the end, though.
"The gift which I am sending you is called a dog, and is in fact the most precious and valuable possession of mankind" -Theodorus Gaza
Baby Jesus cries when the fat redneck doesn't have military-grade firepower.