I clean the bore before switching powders and then figure on 5 or so rounds for the new powder to lay down it's layer in barrel. After that, I clean when accuracy degrades or I switch powders again. I don't see accuracy degrade very often.
Still happily answering to the call-sign Peetza.
You do not HAVE a soul. You ARE a soul. You HAVE a body.
He is no fool who gives what he can not keep to gain what he can not lose.
-Jim Eliott, paraphrasing Philip Henry.