A .410 payload is limited. Even a 3" shell packs 11/16 or in some cases 3/4 ounce of pellets. I think 25 yards is a much more particle distance to pattern a .410 if you are looking at hunting patterns. I have shot a lot of small birds at greater distance but restrict myself to 20-25 yards max on medium size released chukar and pheasant. None wild where I live so they are all pen raised.
30", 24" or 16" patterns are all relative to distance and payload. As to size of pattern it comes down to how big is the density of the pattern, which will humanly kill a bird. A clay target may or may not break with a single hit but live birds almost never die from a single pellet strike. There is always the chance of a golden bb but to rely on such a slime chance is not a sound practice. And risking wounding a bird is not what any of us want.
So I look at 16" patterns as the main point of interest with the extra 3-4" all around as a limited bonus area. So call it 16-24" pattern but much great weight placed on the 16" portion. And don't get wrapped up into percentage like many do. It is evenness of pattern and size of the killing zone which matters. I don't care if the numbers are 50%, 60% or 70%. I want to know if I have a 12", 16", 18" or a 20" effective pattern. To get a real feel for what you have you need to shoot a lot of patterns. But since you are not going to count every little pellet hole that is not that big of a deal. Again it is size not numbers which I care about.
