If I look down the bore of my rifle, it looks nice and clean but when I put Barnes bore cleaner on a patch and run it through, it comes out black or purple so I know fowling is there. Barnes says barrels have to be very clean to get accuracy from their bullets.
I've seen the way Barnes bullets perform on game (excellent), but they haven't been the most accurate bullet in any gun I've tried them in (like 222 Remington, 22-250, 30/06, 375 H&H Mag., 458 Lott, etc.) so, until I find the secret to accurate loads with them, I'm going to use something else. I've found the accuracy of Nosler, Sierra, Woodleigh and Hornady bullets to be much superior. Even at times I've shot Barnes bullets with meticulously clean barrels, they haven't printed as well as my other choices and they cost quite a bit more.