Ballistic products inc. has copper and nickle plated shot-ITX turkey trauma 13 shot, every size shot cup you would need, over shot cards.
http://www.ballisticproducts.com/bpi tps(Tungsten Propulsion System (TPS)) or their multi metal shot cups much more economical-get 100 for $12.99-- knight-$11.99 for 20 or tc shotcups $12.99 for 20.
you can also get 2 3/4", 3", or 3 1/2" cups- preslit or unslit--just cut with knife or scissors and test 2 or 3 slits-it does make a slight difference in my gun.
Also Eastern maine shooting supplies has trad. wads, etc, track of the wolf has wads and wad punches
as for powder I use Black MZ by Alliant powders. I have allergies and all of the others bother me a lot. close to same velocity and works very well in my older pedersoli with #11 caps for dove and rabbits. Got 7 doves last year in the one day I hunted.
I made the terrible(stupid) mistake of loading the double with Black mz and did not shoot it off at the end day. I intended to hunt again but a couple of days later I was rear ended and injured my shoulder. completely forgot about the pedersoli being loaded. After several months of therapy and cortizone treatments( make that SEVEN months!!!)
I finally realized (remembered) my mistake. So I took it with me to the range with my rifles and tk 2000. cleaned the nipples with a pick, put a couple of caps on and shot each barrel. both barrels went off and felt just as strong as they did in September!!!!