....Zutz...deemed #7.5 too small to kill cleanly.
Zutz apparently hasn't interviewed the grouse I've killed with #7-1/2s and #8s! Over a lifetime of hunting in some of America's best grouse country, I've only once hunted with someone who used #6s, and then only in early season when the leaves are thick. It's all a matter of opinion, of course, but most folks I know opine that #7-1/2s are plenty good to kill the lightly feathered ruffs.
No disrespect intended, but just because a gun writer says something doesn't mean it's gospel. If you doubt that, go back and read Silvio Calabi's absurd panegyric in the current
Shooting Sportsman magazine:
"For any game requiring No. 5 shot or smaller, the 28 can equal or surpass the 12." Sometimes a writer says things just to stir up readers because it sells more copy.
I would venture to guess that more grouse have fallen to #7-1/2s than ever to #7 or #6 shot.