I always cleaned my rifles with a wooden cleaning rod. A few months ago I got a steel cleaning rod, and since then I've been noticing a black material coming from the bore when I was swabbing to dry the bore, some of it looks as though the bore is still fouled. It's not black powder residue as it only appears at the drying stage.
The last time out I used my old wooden rod to clean and no black residue while drying. Nothing changed but the rod.
Could this be some kind of reaction to the stainless steel rod?