I use Winchester Double A and Winchester Orange Target wads primarily and Ox-Yoke 1/2" wads. On occasion I have used ClayBuster wads with no noticeable difference. I have picked up many shot cups in the field and there is no where they have melted. The only difference I can think of is I use Pyrodex rather than true BP but use the terminology interchangeably.

Nothing is foolproof to a sufficiently talented fool.