Well I have had more than my share of crud ring,Now I am very careful on how I clean the original metal preseveritive out of a new gun, I believe that if it is burned into the pores of the metal its part of the problem[I don't know what they are using now] and find that if you get it completely and truly clean of all oil and metal preseveritive then polish with jewelers rouge it not only helps the crud ring big time but makes loading and cleaning easier to. Lee