Wasn't it Keith Rogan who said that 00 buck was the preferred load? I disremember ....
At self defense ranges, and you're not likely to even see one about to getcha much past 10 yards or so, if that, the buckshot will be a solid mass? as such the common wisdom goes .....
Beats me. I never hunted the bigguns & really have no desire, but as with the really big piggies, I'd want something big & solid all the better to break 'em down - screw killin' 'em - I just don't want 'em gettin' anywhere close. Killing's for later.
I'm a wuss that way.