+1 for scorch
I have use of a .410 from brother and use it for squirrels when I want to drive myself crazy. At least in my area, it is very difficult to find .410 ammo in anything but #4 shot. There aren't many pellets in those shells and my .410 being full choke shoots more like a rifle.
Otoh, a nice 2 3/4 load of #8 in 20 guage makes a very nice pattern for old bob white. Scorch is also right about there being quite a few good used 2 3/4 inch 20 guage guns available for reasonable prices.