I will say that after intense carbon cleaning with bronze brush wrapped with patch (hand Dewey rod and only no power tools at all); JB and Butch's, I now see some surface scratches in bore that I did not have before. These are Sinclaire brushes so not El Cheapo's and I was appalled by what I had done to the bore. But I had no other choice than using the brush/patch JB to get the carbon out. This barrel is near end of life with about 1200 rounds through it but it does have life; shoots well or I thought it did. I plan on taking my best load to range and see WTH happens. This made me sick to my stomach seeing the scratches. I had tried a nylon brush wrapped with patch and JB and got nowhere and then switched to bronze which I now am wondering what to do next carbon clean. Maybe after each range session now. I hate carbon