As to buckshot, I think you're stuck with #1 Buck which is a decent size for moderate range shooting. Get a case of the stuff both for practice and in case supplies get scarce. But before you do, try out both Winchester's and Federal's (if Federal still makes 16 gauge #1 buck) to see which one patterns better. Does anyone know if any other manufacturer makes buckshot for the 16 gauge?
Your local sporting goods shop should be able to order it for you but, if all else fails, try here
http://www.goldpaint.net/cgi-bin/nph....tam?uu=108944