Mostly i watch for copper fouling, 1 shot , clean..this bbl (CBI) cleaned up real easy from the start..maybe 4 shots,with a 1 to 1 clean ratio, then three shots...barrel was clean after 3-4 patches.....Cleaned with k-12, let sit, brushed with a NYLON brush, then patches till clean..then to make sure, Montana's extreme copper killer on a patch, sit for 10 min...and patch again....no copper, no nada...clean patches.....boxed it up, sent it to be braked and then nitrided....rsbhunter