The directions for the Bore Snakes make it clear it does not throroughly clean the bore.  It is for "touch-ups" only.  In order to clean well enough to break in the bore you need to use a rod with patches and phosphor-bronze brushes with powder solvent and copper remover.  Clean from the breech, use a bore guide, and a good quality rod.  I like those made by Pro Shot products way better than Dewey's.  They are at:  (217)824-9133