My friend wants a black powder shotgun for duck do you think 12 gauge is ok or does a 10 gauge sound better

a friend of mine wanted to do the same thing. long story, probably like yours if you know what i mean. get the 10 ga, there are plenty of sources to get components for a 10 muzzle loader.

i would think that they would both be similar in performance. Sounds like a fun way to hunt ducks and geese!