Steve-
I'm totally with you on the little .410
The three inch chambers are plenty for close birds (of appropriate size)
My miniature 2-1/2" .410 SxS will flatten close-range pigeons on the wing with 7/16oz of shot over blackpowder.
Also, I kill pigeons at the bay doors of my machine shop with a rimfire 9mm shotgun.
Any of these inner-city pigeons unfortunate enough to linger in the air of my workshop doors looking for a handout get their breast smacked. There are a couple tomcats who know the drill.
They come running when they hear the 'plip' of the little cape gun, on the birds before the feathers settle.
There's no lead hazard either, as these stray cat characters seem to only be interested in the crunchy-yet-squishy pigeon heads.
Seems I have a good deal going with the local cats.
They keep the mice away from my buildings as well!
--Tinker