I have fired a few "unsquare loads", think 3" 20 gauge, and can report that the results, with lead shot, are mostly underwelming. The same loads, in steel, seem to perk up a bit on the pattern board, but, I always lose interest, and start shooting a 12 at that point.
I inherited a bunch of heavy loads for 12 gauge, a lot of it pretty much useless for me (3" lead 4s, 3 1/2" anythings) but, the 1 1/4 oz loads of 5s and 6s sure flatten pheasants. Funny what getting ammunition for free does to one's opinion of it.
Not that I'd buy anymore of it....


Best,
Ted