I get no more practical range from the 12 ga than the 20 ga (when shooting hi-test). Because the limitation for both is confidence in my ability to put the core of the pattern on his head and neck at ranges where you have to consider drop, not the gun/ammo's ability to do the job. And I have no interest in trying to shoot one that far anyway. But the beauty of the larger bores is that I can choke it wider to where I have a lot more margin for error at all ranges due to the dense pattern outside the core, while still having more range than needed to cover for any range estimation errors in the heat of the moment.

The 28 ga reduces my comfortable range to only about 55 yds. The .410 reduces that comfortable range by another 15 yds.