You are correct. Witches Brew will always show black. I use it on badly carboned barrels in conjunction with a bore scope. The worst cases seem to take a couple sets of 10 passes after 300 or more .308 rounds. I think I have posted before and after pictures before. I'll check.

Found them

[Linked Image]
[Linked Image]

Last edited by MikeS; 05/11/24. Reason: added pics