I noticed that also. Dip that bronze brush in solvent and do your barrel and the next three patches come out dirty looking. I always blame the solvent and the brush. Actually I use the brush only when I suspect lead, copper, or plastic fowling in the bore, and that is not that often. Maybe once every several times to the range.. I do like to run Simple Green patches through the barrel ASAP after shooting, as that stuff will really pull the fowling out of the bore..