#2 or #3 shot would be a great goose load, if in lead. old saying:
"less powder, more lead, shoots far, kills dead"
This worked well in my "Field London" 12 bore BP loads SxS, second in trap, shooting against a hammered, single shot choked gun (a bunch of those in the match).
Used 2 3/4 dram load with 1 1/4oz. shot. Smoked most of them. Had one more miss (easy shot too but missed) than the winner.
I am not suggesting you use this load, but the basic concept.
-------------------- Daryl
"a gun without hammers is like a Spaniel without ears" King George V