One summer many years ago I thought #9's would be just the ticket for starlings around the barn. I killed some. On rare occasions I actually pulled a feather or two off. Some showed no sign of being hit but flew 40 or 50 yds and fell dead.
I switched to #8 and my kill ratio improved. Maybe I was just getting to be a better shot. But seldom did I pull feathers and it was still common to see them fly another 50 yds before dropping.
I changed to #7.5 and, once I got accustomed to a little more choke, I was completely satisfied. Birds died instantly, often in a hail of feathers without a second wingbeat,and sailed only as far as momentum would carry them.
Since that summer 40 years ago I've never shot a live bird with anything smaller than #7.5. Every game bird that is brought to bag was killed. To some people that validates the shot size that was used, no matter how small. But shooting starlings in an open pasture taught me that birds can be wounded and crippled, or perhaps soak up a mortal load of small pellets, and show no outward sign. My dogs have retrieved a number of grouse & WC that we wouldn't have searched for had it not been for a feather floating on the breeze. They've also retrieved birds with broken wing bones that may not have been shattered with a smaller pellet.
I only have 20, 16 and 12 gauges and find 1 ounce of #7.5 through the appropriate choke to be more than adequate for everything from starlings to grouse and skeet targets to FITASC. When I load 7/8 for targets (for no other reason than recoil reduction), I drop to #8 for virtually the same pellet count. Lately I've loaded 3/4 ounce for 20ga targets and use #8.5 for the same reason; nearly the same pellet count as my 1 ounce of #7.5.
