Are you finding it is taking longer to get a clean barrel now that it is showing Fire Checking {#27} ?This was 7-11 1st 3@1000 Barts Gungners, on 7-12 1st 3 @1000, then 9 @1000 ,pic 0016 carbon ring, #25 clean,# 27 start of rifling after 1992 shots, gonna have to order More of Barts Bullets.
I had a barrel like that and it was shooting OK but taking a long time and a lot of effort to get it back clean as the fire checking seemed to have a lot of copper embedded in the cracks and showing after an apparent clean but then leaving some Bore Tec Cu+2 in over night. Accuracy was good in clean barrel but once 10-15 shots started to wander. The barrel had about 3K+ rounds through it {I was the third owner} and it cost me the club F Open for the year when it finally just died in the last two events. It just would not group any more with erratic fliers 1-3 out of 10 shots.