Ok, no such creature I know...other than a brush and jb or iosso... So, are there really certain powders that form carbon rings more, or less? I shoot mostly 6mm Dashers, 22 br's enough that it can be an issue after 1 or 2 matches. I shoot Varget, RL16, lever evouloution (243 lbc) . I have RL 15.5 , VV N140 that I could go to. I'm also looking into VV N150....any experience with carbon for these , or other powders?? Thanks, rsbhunter