A nylon brush does exactly NOTHING, they are useless. If you are going to brush use a good bronze brush and when they get where they feel weak throw them away and get you a new one. I have found the best regimen is push a dry patch to get the loose crud out then brush with a good bronze brush at least 3 strokes(stroke = in and back) then two wet patches and a final dry one. I have tested almost every method and checked it with a bore scope and have found this regimen is the least to get by with that leaves my barrel completely clean. If you can try to push the brush ALMOST all the way out of the crown except the last 1/16 inch then pull it back this keeps the rod from falling down to the bore. This is what I do and seems to work very well, there are legion other methods.
Mike Cameron
What about a bristle brush?? Some feel brass to harsh.