That can depend on many factors with almost any Powder in an AR type rifle . Barrel length , gas system , weight of the projectile's being used & even the primer used for the loading . Round count one way or the other can also have a impact .
I have been using WC 846 Powder for many years & its a pretty dirty burning powder , but when used in some loadings , is not so dirty. I would imagine the new Powders , like CFC , that have a supposedly anti fouling formula , would be clean with any loading combo . Since most of the popular Powders have been unavailable for a very long time , we have had to use not so popular Powders , even though they work great , not the first choice to use with our caliber or loadings for them .
The AR ,DI gas system, is a dirty system & its just the way it is . Be it scraping the tail of the Bolt or the Piston of a piston system , burnt Powder residue is going to collect some where & will need cleaning .