Why exactly did you buy a rifled bbl if you' re not planning on using slugs through it? They don' t pattern for crap with shot of any kind.

On the up side, you' re not going to hurt your bbl by shooting shot through it, remember, you' ve got a shot cup, so your shot isn' t going to contact your bbl anyway, I' d just recommend staying away from paper component shells, as the paper wads would wear down your rifling more quickly than plastic wads, although neither really should prove to wear a bbl any faster than lead slugs.